微藻活体生物材料易受胃酸、消化酶及机械应力影响

Hepatic encephalopathy (HE) is a serious neuropsychiatric complication of acute or chronic liver failure. It occurred in approximately 40% of acute liver failure cases and affected 30%–45% of patients with chronic liver failure or decompensated cirrhosis. Hyperammonemia is widely recognized as a central pathogenic factor in the pathogenesis of HE. Rifaximin (RIF), a non‐absorbable oral antibiotic, was widely used to manage HE by modulating gut microbiota and reducing ammonia production. However, its clinical efficacy remained suboptimal due to poor aqueous solubility, limited dispersibility, and inadequate gastrointestinal retention. These limitations were further exacerbated in severe cases, owing to restricted oral dosing, recurrence associated with poor adherence, and potential risks of antimicrobial resistance and infection‐related adverse events. This study presented a microalgae‐nanoparticle hybrid system (SP@RIF) for drug delivery, in which RIF‐encapsulated nanoparticles (RIFnano) were electrostatically loaded onto the surface of Spirulina platensis (SP), aiming to improve the oral delivery and therapeutic efficiency in HE treatment. RIFnano exhibited significantly enhanced antibacterial activity compared to free RIF. SP@RIF demonstrated prolonged gastrointestinal retention and sustained drug release profiles. In mouse models of HE, oral administration of SP@RIF markedly reduced systemic ammonia levels and improved behavioral outcomes. Furthermore, SP@RIF enhanced intestinal barrier function, attenuated systemic inflammation and neuroinflammation, ameliorated cognitive impairments, and modulated the gut microbiota. Importantly, these therapeutic benefits were achieved without observable toxicity. These findings highlight SP@RIF as a potential therapeutic strategy for treating HE.

Gouty arthritis (GA) is a type of inflammatory arthritis caused by the deposition of monosodium urate crystals. Current clinical therapies fail to simultaneously reduce uric acid (UA) levels and alleviate inflammation. Previous studies have demonstrated that Euglena (Eug) polysaccharides can effectively adsorb UA. Colchicine (Col), the most prescribed medication for GA, exhibits anti-inflammatory effects but is associated with significant side effects. Here, we developed an oral microalgae-based hydrogel system (Eug-Col@Fucar) utilizing Fucar to load the Eug-Col complex, aiming to synergistically reduce UA levels and alleviate inflammation in GA treatment. Eug-Col@Fucar regulated release characteristics and enhanced intestinal retention, thereby mitigating the side effects associated with oral Col. The oral administration of Eug-Col@Fucar could inhibit the progression of GA by eliminating reactive oxygen species, reprogramming the inflammatory microenvironment to promote cell polarization towards M2-like anti-inflammatory cells, inhibiting the NLRP3-IL-1β pathway, and reducing the expression of pro-inflammatory factors. Additionally, Eug-Col@Fucar improved bile acid metabolism in vivo, alleviating the intestinal-hepatic circulation damage caused by Col. This study presents a safe, simple, and highly effective treatment strategy for managing GA and alleviating the gastrointestinal side effects that arise from the long-term administration of Col, demonstrating clinical practicability.

Irreversible electroporation (IRE) is a novel local tumor ablation technique that can potentially stimulate immune responses. However, IRE alone cannot effectively activate the immune system or prevent distant metastases. Therefore, this study utilized the biocompatibility of Chlorella vulgaris (C. vulgaris) and polydopamine (PDA) adhesive properties to encapsulate a PD‐1 inhibitor (PI). The PDA coating protects the drug from degradation by stomach acid and enhances its intestinal absorption. This carrier demonstrates excellent in vivo drug release control and biodistribution, significantly increasing the oral bioavailability of PI. Combining IRE with this natural carrier significantly improves the therapeutic efficacy, which increases the local drug concentration and activates the immune system. This system demonstrates significantly improved therapeutic efficacy against local tumors compared with PI or IRE alone and significantly reduces PI‐associated side effects. A convenient oral delivery system is developed using this readily available natural micro‐carrier that not only improves the therapeutic effect of IRE but also mitigates its adverse effects, indicating significant potential for clinical applications. This discovery offers a new strategy for hepatocellular carcinoma treatment with the potential to improve patient outcomes.

Abstract White spot disease (WSD) is a longstanding and serious viral disease of various shrimp species that has caused high mortality rates for many decades. Currently, there is no practical method to control this disease. Therefore, we have explored the development of a novel vaccine-based method to control this disease using transgenic algae. During infection by white spot syndrome virus (WSSV), the interaction between viral envelope proteins and cell surface protein receptors on target cells is the key step of viral entry and replication. Hence, transgenic lines of the green microalga Chlamydomonas reinhardtii harbouring a WSSV VP28 viral envelope protein were created as an oral delivery system for vaccinating shrimp. Two separate transplastomic lines containing wild-type and codon optimized gene sequences for VP28 were evaluated for recombinant protein levels. Only the codon optimized line gave rise to detectable VP28 in western blot analysis, which demonstrated that optimization for chloroplast codon bias improved the efficiency of expression and that the gene design produced a favourable RNA secondary structure with suitable free energy for translation. In addition, bile salt and acid tolerance tests demonstrated that this transgenic Chlamydomonas can tolerate mildly acidic (pH 5.0) conditions and 0.30% bile salts. These features indicated that algal cells are suitable for delivering viral antigens through a shrimp's digestive system. In WSSV infection experiments, the highest survival rate (87%) was recorded in shrimps fed with the codon optimized VP28 line mixed into their feed, indicating that this line could be employed in the control of WSSV spread in shrimp populations. This algal strategy offers a new, efficient, fast and less labour-intensive method for the control of other diseases in aquatic animals through oral delivery.

The combination of cranial radiotherapy and chemotherapy may cause brain damage and cognitive dysfunction, therefore developing protective strategies for the treatment of chemoradiotherapy-induced brain injury is of great significance. Deferoxamine is an efficient iron chelator to inhibit ferroptosis which induced by radiotherapy and chemotherapy, but it has low oral bioavailability and difficulty in crossing the blood brain barrier (BBB), which limit its clinical translation. Herein, we constructed an orally microalgae-metal-organic framework (MOF) integrated drug delivery system (DFO@MOF@SP) for the protection of chemoradiotherapy-induced ferroptosis-related brain injury. Spirulina platensis (SP) can improve the biodistribution of nano-drugs in the intestines and enhance their oral bioavailability. The MOF nanoparticles as vectors for the delivery of deferoxamine (DFO), and modified by Angiopep-2 to improve their ability to cross the BBB (DFO@MOF). The in vitro and in vivo experimental results displayed that DFO@MOF@SP system has high safety and can exert good neuroprotective effect. We confirmed that DFO@MOF@SP system could improve the cognitive function and alleviate neurogenesis impairment and glial activation in mice subjected to chemoradiotherapy, and its neuroprotective mechanisms mainly include inhibiting ferroptosis and regulating gut microbiota. This study can provide new direction for the treatment of brain injury in patients undergoing cranial radiotherapy and chemotherapy.

The gut microbiota is one of the essential contributors of the pathogenesis and progress of inflammatory bowel disease (IBD). Compared with first-line drug therapy, probiotic supplementation has emerged as a viable and secure therapeutic approach for managing IBD through the regulation of both the immune system and gut microbiota. Nevertheless, the efficacy of oral probiotic supplements is hindered by their susceptibility to the gastrointestinal barrier, leading to diminished bioavailability and restricted intestinal colonization. Here, we developed a bacteria-microalgae symbiosis system (EcN-SP) for targeted intestinal delivery of probiotics and highly effective treatment of colitis. The utilization of mircroalge Spirulina platensis (SP) as a natural carrier for the probiotic Escherichia coli Nissle 1917 (EcN) demonstrated potential benefits in promoting EcN proliferation, facilitating effective intestinal delivery and colonization. The alterations in the binding affinity of EcN-SP within the gastrointestinal environment, coupled with the distinctive structural properties of the SP carrier, served to overcome gastrointestinal barriers, minimizing transgastric EcN loss and enabling sustained intestinal retention and colonization. The oral administration of EcN-SP could effectively treat IBD by reducing the expression of intestinal inflammatory factors, maintaining the intestinal barrier and regulating the balance of gut microbiota. This probiotic delivery approach is inspired by symbiotic interactions found in nature and offers advantages in terms of feasibility, safety, and efficacy, thus holding significant promise for the management of gastrointestinal disorders. Supplementary Information The online version contains supplementary material available at 10.1186/s12951-024-02647-6.

&NA; Recombinant proteins produced by biological systems such as bacteria, yeasts, mammalian and insect cell cultures are widely used for clinical or industrial purposes. Most therapeutic protein drugs require purification, cold chain, and injection, which make them prohibitively expensive and hinders their widespread use. Here, we describe a new economical oral vaccination platform using algae and evaluated its potential for the delivery of recombinant drugs using GFP expressed in the chloroplast of algal cells. The transplastomic algae expressing recombinant GFPs were freeze‐dried for long‐term storage at ambient temperature and for easy handling in feeding. GFPs bioencapsulated by lyophilized Chlamydomonas reinhardtii were found intact without degradation for several months at ambient temperature. The expression level of GFP in the lyophilized algae was estimated at 0.47 &mgr;g/mg dry weight. The GFPs bioencapsulated and orally delivered to Danio rerio were immunostained and observed in the intestinal tissues using a confocal microscope. Furthermore, the uptaken GFPs in the intestine were detected in the blood using ELISA and the detected level was 5.4 ng of GFP/&mgr;l of serum. These results demonstrate that microalgae can be a viable protein production and oral delivery system to vaccinate fish. The results give greater justification to continue exploring the concept of microalgal‐based oral vaccines. The potential of the technology would greatly benefit aquaculture farmers by providing them with affordable, environmentally sustainable, and user‐friendly vaccines.

Irreversible Electroporation Immunotherapy In article number 2409381, Min Zhou, Zhe Tang, and co‐workers present a microalgae‐based drug delivery system, showcasing the oral administration of engineered microalgae carrying immunomodulators for liver cancer treatment. In synergy with irreversible electroporation technology, it activates systemic anti‐tumor immunity. Through innovative collaboration between biomaterials and physiotherapy, it breaks through the limitations of traditional treatments and provides a new paradigm for precise immunotherapy of liver cancer.

Faecal microbiota transplantation (FMT) has emerged as a transformative therapy for Clostridioides difficile infections and shows promise for various GI and systemic diseases. However, the poor patient acceptability and accessibility of ‘conventional’ FMT, typically administered via colonoscopies or enemas, hinders its widespread clinical adoption, particularly for chronic conditions. Oral administration of FMT (OralFMT) overcomes these limitations, yet faces distinct challenges, including a significant capsule burden, palatability concerns and poor microbial viability during gastric transit. This review provides a comprehensive analysis of emerging strategies that aim to advance OralFMT by: (1) refining processing technologies (eg, lyophilisation) that enable manufacturing of low-volume FMT formulations for reducing capsule burden and (2) developing delivery technologies that improve organoleptic acceptability and safeguard the microbiota for targeted colonic release. These advancements present opportunities for OralFMT to expand its therapeutic scope, beyond C. difficile infections, towards chronic GI conditions requiring frequent dosing regimens. While this review primarily focuses on optimising OralFMT delivery, it is important to contextualise these advancements within the broader shift towards defined microbial consortia. Live biotherapeutic products (LBPs) offer an alternative approach, yet the interplay between OralFMT and LBPs in clinical practice remains unresolved. We postulate that continued innovation in OralFMT and LBPs via a multidisciplinary approach can further increase therapeutic efficacy and scalability by enabling disease site targeting, co-delivery of therapeutic compounds and overcoming colonisation resistance. Realising these goals positions OralFMT as a cornerstone of personalised care across a range of diseases rooted in microbiome health.

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Rationale: Exogenous supplementation of beneficial intestinal bacteria can alleviate the behavioural symptoms of psychiatric disorders, such as autism spectrum disorder (ASD), through gut-brain interactions. However, the application of beneficial bacteria, such as Lactobacillus reuteri (L. reuteri), for treating ASD is hindered by limited gut colonization. Methods: Utilizing Spirulina platensis (SP) as a natural microcarrier for intestinal bacteria, a safer and more natural binding approach was employed to bind intestinal bacteria to the surface of SP to produce SP-intestinal bacteria. Due to the high adhesion efficiency and long residence time of SP in the intestines, SP-intestinal bacteria exhibit stronger intestinal colonization ability and better therapeutic effects on ASD. Results: SP is an effective carrier that can bind and deliver bacteria of different shapes and with different gram-staining properties. SP-intestinal bacteria exhibited enhanced colonization capabilities both ex vivo and in vivo. Further research showed that SP-L. reuteri had greater intestinal colonization efficiency than L. reuteri. SP-L. reuteri showed a stronger therapeutic effect on alleviating social deficits in an ASD mouse model by modulating the gut microbiota, enhancing intestinal barrier integrity, reducing lipopolysaccharide entry into the blood and mediating the neuroinflammatory response in the paraventricular thalamic nucleus. Conclusions: This study reports a microalgae-assisted intestinal bacterial delivery system for enhancing intestinal bacterial transplantation for gut-brain axis- or other intestinal-related diseases.

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3D Printing is an innovative technology within the pharma and food industries that allows the design and manufacturing of novel delivery systems. Orally safe delivery of probiotics to the gastrointestinal tract faces several challenges regarding bacterial viability, in addition to comply with commercial and regulatory standpoints. Lactobacillus rhamnosus CNCM I-4036 (Lr) was microencapsulated in generally recognised as safe (GRAS) proteins, and then assessed for robocasting 3D printing. Microparticles (MP-Lr) were developed and characterised, prior to being 3D printed with pharmaceutical excipients. MP-Lr showed a size of 12.3 ± 4.1 µm and a non-uniform wrinkled surface determined by Scanning Electron Microscopy (SEM). Bacterial quantification by plate counting accounted for 8.68 ±0.6 CFU/g of live bacteria encapsulated within. Formulations were able to keep the bacterial dose constant upon contact with gastric and intestinal pH. Printlets consisted in oval-shape formulations (15 mm × 8 mm × 3.2 mm) of ca. 370 mg of total weight, with a uniform surface. After the 3D printing process, bacterial viability remained even as MP-Lr protected bacteria alongside the process (log reduction of 0.52, p>0.05) in comparison with non-encapsulated probiotic (log reduction of 3.05). Moreover, microparticle size was not altered during the 3D printing process. We confirmed the success of this technology for developing an orally safe formulation, GRAS category, of microencapsulated Lr for gastrointestinal vehiculation.

Background: The oral application of adenovirus is hindered by its poor in vitro storage stability and rapid degradation by gastric acid. To address this, a biomimetic oral adenovirus delivery system (CSP-AdV@LYO) was constructed based on three key properties of natural chrysanthemum sporopollenin (CSP): chemical inertness, intelligent “acid-shrinking/alkali-swelling” responsiveness, and mucosal adhesion via its spike structures, aiming to enhance oral stability and delivery efficiency. Methods: First, low-allergenic chrysanthemum pollen was screened using proteomics and a zebrafish allergy model. High-purity sporopollenin (SPO) was then extracted via an acidolysis method, followed by systematic characterization of its morphology, particle size, zeta potential, contact angle, and reversible acid-shrinking/alkali-swelling behavior. Subsequently, a CSP-AdV@LYO formulation was prepared by optimizing a cryoprotectant formulation (sucrose:gelatin = 1:1) and a vacuum loading process. Its protective and release properties were evaluated in vitro using simulated gastric and intestinal fluids, and its long-term stability was assessed. Further in vivo studies in mice assessed its intestinal colonization efficiency. The adhesion mechanism of the sporopollenin spike structures was investigated through mucosal retention experiments. Results: Mucosal retention experiments confirmed that the spike structures on the sporopollenin surface enhanced retention by approximately 3-fold through mechanical interlocking compared to smooth particles. In long-term stability tests, the viral genome copy number retention rate was improved more than 10-fold compared to the virus stock solution. The system enabled a steady and controlled release of the virus in simulated intestinal fluid, with the released virus maintaining its infectivity. In vivo studies demonstrated that CSP-AdV@LYO promoted efficient intestinal colonization and reduced acute mortality from 75% (AdV@LYO group) to 25%. Conclusions: By leveraging the unique physicochemical properties of chrysanthemum sporopollenin, this study successfully developed a biomimetic oral delivery system for live adenovirus that provides gastric acid protection, intelligent pH-responsive release, and mucosal adhesion. This system significantly enhances the oral stability and intestinal delivery efficiency of adenovirus while reducing systemic exposure risks. It offers a novel biomimetic strategy for the oral delivery of adenovirus and other biological macromolecules.

This study aimed to assess Spirulina platensis, Chlorella vulgaris, Scenedesmus quadricauda, and Lagerheimia longiseta microalgae potential as protective agents for probiotic cultures [(Lactobacillus acidophilus (La-05) and Lacticaseibacillus casei (Lc-01)] during freeze-drying, refrigeration storage (4 °C, 120 days), and in vitro simulated gastrointestinal conditions (SGIC). The occurrence of membrane damage and ultrastructural aspects of the cells were also verified. Fructooligosaccharides (FOS) were used as a positive control and saline solution as a negative control. The effects of the cryoprotectants on probiotic survival depended on the tested probiotic culture and microalgae biomass. For La-05, all tested cryoprotectants caused a lower reduction in probiotic counts during the freeze-drying and up to 90 days of storage. S. platensis kept higher probiotic counts during storage, while C. vulgaris protected the probiotic against the SGIC. L. longiseta decreased the probiotic membrane damage, mainly due to the production of exopolysaccharides, which was observed in the scanning electron microscopy (SEM). For Lc-01, all tested cryoprotectants promoted a lower reduction in probiotic counts up to 120 days of storage. FOS and S. quadricauda protected the probiotics during freeze-drying and refrigeration storage, while C. vulgaris protected the probiotic against the SGIC and caused lower membrane damage, mainly due to physical protection observed in SEM. In conclusion, microalgae biomasses exerted similar or better cryoprotectant effects on probiotics than FOS, a recognized cryoprotective agent.

Gastrointestinal tract toxicity represents a serious adverse effect of chemotherapy, leading to reduced quality of life and survival. For instance, irinotecan (CPT-11) usually causes severe gastrointestinal toxicity, with a lack of effective therapeutic interventions, making treatment often unsustainable. Therefore, development of an effective and safe therapy is crucial for improving chemotherapy efficacy and the patients’ quality of life. In this work, we developed a novel approach involving the helical-shaped cyanobacterium microalgae, Spirulina platensis (SP), to carry the bornyl acetate (BA)-loaded chitosan nanoparticles to enhance drug retention in the small intestine. We demonstrated the protection effect of BA against chemotherapy-induced intestinal injury using an epithelial cell model. In a mouse model, orally administered BA-ChNPs@SP accumulated in the small intestine and attenuated inflammation by reducing dsDNA release and oxidative stress. This was concomitant with the restoration of the intestinal barrier and modulation of the immune microenvironment. This work suggests the promise of the microalgae-carrying nanomedicine strategy for treatment of intestinal diseases, emphasizing its potential in addressing chemotherapy-induced gastrointestinal complications.

Probiotics, as live microbial agents, play a pivotal role in modulating host microbiota balance, enhancing immunity, and improving gastrointestinal health. However, their application is hindered by critical challenges, such as inactivation during processing, storage, and gastrointestinal delivery, as well as low colonization efficiency. This article comprehensively reviews recent advances in probiotic delivery systems, focusing on innovative technologies, including hydrogels, nanocoatings, emulsions, and core–shell microgels. It provides an in-depth analysis of natural polyphenol-based nanocoatings and metal–phenolic network (MPN) single-cell encapsulation strategies for enhancing bacterial survival rates while highlighting the unique potential of microalgae-based bio-carriers in targeted delivery. Research demonstrates that well-designed edible delivery systems can effectively preserve probiotic viability and enable controlled intestinal release, offering novel strategies to reshape a healthy gut microbiome. While these systems show promise in maintaining probiotic activity and gut colonization, challenges remain in safety, scalable production, and clinical translation. Overcoming these barriers is crucial to fully harnessing probiotics for human health.

Chlorella vulgaris and Tetraselmis chuii are two microalgae species already marketed because of their richness in high-value and health-beneficial compounds. Previous studies have demonstrated the biological properties of compounds isolated from both microalgae, although data are not yet available on the impact that pre-treatment and gastrointestinal digestion could exert on these properties. The aim of the present study was to analyze the impact of the biomass pre-treatment (freeze/thaw cycles plus ultrasounds) and simulated gastrointestinal digestion in the bioaccessibility and in vitro antioxidant activity (ABTS, ORAC, Q-FRAP, Q-DPPH) of the released digests. The cell wall from microalgae were susceptible to the pre-treatment and the action of saliva and gastric enzymes, releasing bioactive peptides and phenolic compounds that contributed to the potent antioxidant activity of digests through their radical scavenging and iron reduction capacities. Our findings suggest the potential of these microalgae against oxidative stress-associated diseases at both, intestinal and systemic level.

Gut microbiota modulates gut-brain crosstalk in Parkinson's disease (PD), yet effective therapies are still lacking. Herein, we report an orally administrable microalgae-nanozyme platform (SP@SKCN) via combining sulfur/potassium (S/K) co-doped carbon nitride (SKCN) with Spirulina platensis (SP), offering a novel therapeutic strategy for PD. Uniform S-K co-doping significantly narrows the bandgap of carbon nitride (2.2 eV), endowing SKCN with high near-infrared (NIR)-photocatalytic activity and a star-shaped network morphology, realizing NIR-driven water splitting for H2/O2 generation. Meanwhile, SKCN exhibits superoxide dismutase (SOD)/catalase (CAT) mimetic enzyme activities, efficiently scavenging reactive oxygen species (ROS) and synergistically alleviating inflammation. SP incorporation protects SP@SKCN from gastric acid degradation, prolongs its intestinal retention time, and mediates sustained SKCN release. Notably, SP@SKCN remarkedly improves motor deficits, gastrointestinal dysfunctions, and dopaminergic neuron loss in PD mice. 16 S rRNA sequencing and targeted metabolomics reveal that SP@SKCN treatment reverses both PD-associated microbiota changes and the MPTP-induced reduction in indole-3-lactic acid (ILA). Further experiments indicate that SP@SKCN alleviate intestinal inflammation and gut barrier disruption, consequently attenuating systemic inflammation. Mechanistically, SP@SKCN restore the ILA/aryl hydrocarbon receptor (AHR)/NF-κB signaling caused by disturbed gut microbiota mediated the glial cells activation, which eventually reduce dopaminergic neuron death. Collectively, SP@SKCN ameliorates PD via regulating the microbiota-ILA-brain axis.

Irritable Bowel Syndrome (IBS) is a chronic gastrointestinal disorder associated with dysregulation of the gut-brain axis. Current treatment approaches often lack long-term efficacy and target specificity, and there are no drugs or formulations specifically targeting this disease. Owing to chronic and intermittent gastrointestinal motility disturbances, the pharmacokinetic parameters of IBS patients change significantly. In this research, we develop an oral engineered microalgae biosystem by integrating microalgae with myricetin nanoparticles to enhance the treatment of IBS. After cultivation and micro-nano transformation, the engineered microalgae can be captured by intestinal villi and remain attached. The nano-coating further enhances the adhesion to intestinal tissue and resistance to gastric acid. This biosystem aims to address the pharmacokinetic complications in IBS that are not resolvable by enteric-coated capsules. Interestingly, microalgae seem to exert their prebiotic potential, assisting myricetin in increasing short-chain fatty acids levels and further regulating IBS multi-organ symptoms through the gut-brain axis. Irritable bowel syndrome (IBS) is a complex and chronic gastrointestinal disorder associated with dysregulation of the gut-brain axis. Here, the authors develop an engineered microalgae that can address the pharmacokinetic complications of IBS and achieve the treatment of multi-organ symptoms.

Despite their large number and diversity, microalgae from only four genera are currently cultivated at large-scale. Three of those share common characteristics: they are cultivated mainly autotrophically and are extremophiles or tolerate “extreme conditions.” Extreme growth conditions aid in preventing contamination and predation of microalgae, therefore facilitating outdoor cultivation. In search for new extremophilic algae suitable for large-scale production, we investigated six microalgal strains able to grow at pH below 3 and belonging to four genera; Stichococcus bacillaris ACUF158, Chlamydomonas acidophila SAG 2045, and Chlamydomonas pitschmannii ACUF238, Viridiella fridericiana ACUF035 and Galdieria sulphuraria ACUF064 and ACUF074. All strains were cultivated autotrophically at light intensity of 100 and 300 μmol m−2 s−1 and pH between 1.9 and 2.9. The autotrophic biomass productivities were compared with one of the most productive microalgae, Chlorella sorokiniana SAG 211-8K, grown at pH 6.8. The acid tolerant strains have their autotrophic biomass productivities reported for the first time. Mixotrophic and heterotrophic properties were investigated when possible. Five of the tested strains displayed autotrophic biomass productivities 10–39% lower than Chlorella sorokiniana but comparable with other commercially relevant neutrophilic microalgae, indicating the potential of these microalgae for autotrophic biomass production under acidic growth conditions. Two acid tolerant species, S. bacillaris and C. acidophila were able to grow mixotrophically with glucose. Chlamydomonas acidophila and the two Galdieria strains were also cultivated heterotrophically with glucose at various temperatures. Chlamydomonas acidophila failed to grow at 37°C, while G. sulphuraria ACUF64 showed a temperature optimum of 37°C and G. sulphuraria ACUF74 of 42°C. For each strain, the biomass yield on glucose decreased when cultivated above their optimal temperature. The possible biotechnological applications of our findings will be addressed.

Harvesting of microalgae is a cost-consuming step for biodiesel production. Cellulose has recently been studied as a biocompatible and inexpensive flocculant for harvesting microalgae via surface modifications such as cation-modifications. In this study, we demonstrated that cellulose nanofibrils (CNF) played a role as a microalgal flocculant via its network geometry without cation modification. Sulfur acid-treated tunicate CNF flocculated microalgae, but cellulose nanocrystals (CNC) did not. In addition, desulfurization did not significantly influence the flocculation efficiency of CNF. This mechanism is likely related to encapsulation of microalgae by nanofibrous structure formation, which is derived from nanofibrils entanglement and intra-hydrogen bonding. Moreover, flocculated microalgae were subject to mechanical stress resulting in changes in metabolism induced by calcium ion influx, leading to upregulated lipid synthesis. CNF do not require surface modifications such as cation modified CNC and flocculation is derived from network geometry related to nanocellulose size; accordingly, CNF is one of the least expensive cellulose-based flocculants ever identified. If this flocculant is applied to the biodiesel process, it could decrease the cost of harvest, which is one of the most expensive steps, while increasing lipid production.

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Bioplastic with significantly enhanced mechanical properties, impact resistance, and compatibility can be obtained from spirulina powder by a facile and green conversion process. The conversion is proceeded through the molecular mechanism of the protein ɑ‐β transformation, which is induced by the extensive hydrogen bonding interactions and thermal stress. The morphology, microstructure, chemical composition, dispersability, and thermal properties of the bioplastic are characterized by scanning electron microscopy (SEM), X‐ray diffraction (XRD), Fourier‐transformed infrared spectroscopy (FTIR), dynamic light‐scattering (DLS), thermogravimetric (TGA), and differential scanning calorimetric (DSC). Both the SEM and XRD results reveal an anisotropic extension of the spirulina powder after conversion, where microstructures with higher aspect ratios and more planar facets can be observed, indicating the formation of sufficient β‐phase in the spirulina protein. Moreover, a higher intensity of multimeric hydrogen bonding structure is observed for the bioplastic, which leads to a higher dispersability and compatibility. The bioplastic shows promising applications in high‐performance flexible polyurethane foams for impact protection, which significantly improves the tensile strength, compressive strength, impact energy absorption, and thermal stability of the flexible foam, revealing its great potential in the next‐generation eco‐friendly plastics.

In this study, we propose a self-limiting growth model forBacillus subtilisspores confined within porous polyacrylamide (PA) hydrogels. We observed thatB. subtilisspores germinate into vegetative cells within the hydrogel matrix, forming spherical colonies. These colonies expand until the mechanical stress they exert on their environment surpasses the yield stress of the hydrogel, leading to formation of a nonpermeable layer that halts nutrient diffusion and forces the bacteria to resporulate. These novel observations suggest a model to explain why bacterial growth in confined environments and material interfaces may be limited, providing insight for natural phenomena and biotechnological applications involving bacterial encapsulation.

Microalgae is becoming a crucial research topic because of global resource shortage, pollution, and population growth make. This paper focuses on the mechanical properties of microalgae cells, including the characterization of cell stiffness, adhesion force, and deformability and their applications in growth regulation and breeding. Understanding cell behavior provides significance and serves as a basis for screening and cultivating microalgae. It analyzes the effects of mechanical factors, including light, temperature, and fluid shear stress on microalgae growth and emphasizes the importance of optimizing these conditions. It discussed high-throughput screening techniques in microalgae breeding and the correlation between mechanical properties and superior traits. With regard to microalgae processing, the paper examines the role of cellular biomechanics in harvesting, extraction, and product quality optimization, including the selection and optimization of harvesting methods, the evaluation of cell fragmentation efficiency, and the relationship between product quality and mechanical properties. The paper presents case studies on specific microalgae species like Chlamydomonas reinhardtii and highlights its potential to optimize culture conditions, promote product diversification, drive technological innovation, support environmental protection, and enhance interdisciplinary cooperation.

This study investigates the biochemical methane potential (BMP) of microalgal biomass, introducing a novel cells disruption method using quartz powder (SiO2). A two-phase algae cultivation, involving nitrogen deprivation and salinity shifts, was employed to biochemically modify the biomass of two brackish green algae strains, Chlorella vulgaris and Monoraphidium contortum, enhancing their methane (CH4) production potential. Mechanical disruption of the algal cells further increased BMP, with C. vulgaris yielding 305 mL CH4/g volatile solids (VS) and M. contortum reaching 324 mL CH4/g VS, reflecting respective increases of 51 % and 86 %. The integration of this efficient mechanical cell disruption method with a simple, stress-based cultivation strategy presents significant potential for enhancing the methane yield of microalgal biomass.

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Polydiacetylenes are deeply investigated for their mechanofluorochromic behavior: the blue, non‐emitting solid phase, obtained by photopolymerization of the diacetylene precursor, is converted to the red, emitting one by a mechanical stimulus. Inspired by the great potentiality of these compounds to act as microscale force probes, the mechanofluorochromism is implemented in microalgae biotechnology. Indeed, mechanical solicitations in a microfluidic chip can weaken the cellular envelope and facilitate the extraction of high‐added value compounds produced by the microalgae. Herewith, a polydiacetylene‐based mechanofluorochromic sensor is reported to be able to detect the stress applied to microalgae in microchannels. A triethoxysilane diacetylene precursor is designed that photopolymerizes in a purple, low‐emissive phase, and is converted to the red, high‐emissive phase upon mechanical stress. Hereafter, a protocol is set up to chemically graft in the microfluidic channels a polydiacetylene layer, and eventually proves that upon compression of Chlamydomonas reinhardtii microalgae in restricted areas, the friction stress is revealed by the mechanofluorochromic response of the polydiacetylene, leading to a marked fluorescence enhancement up to 83%. This prototype of microscale force probes lays the ground for microscale stress detection in microfluidics environments, which can be applied not only to microalgae but also to any mechano‐responsive cellular sample.

Gelatine-gum Arabic coacervated microcapsules were prepared using complex coacervation followed by spray drying, with L-carvone, limonene, or hexyl salicylate encapsulated as a model flavour or fragrance oil. The influences of different types of core oil or further treatments including maltodextrin coating or glutaraldehyde crosslinking on size, morphology, payload, encapsulation efficiency and mechanical strength of the resulting microcapsules were investigated. Spherical microcapsules with polynuclear core-shell structure were fabricated. The encapsulation efficiency ranged from 5.0 ± 0.4% to 89.0 ± 1.2% for different core oils and 21.1 ± 0.1% to 89.0 ± 1.2% after different treatments. The highest encapsulation efficiency of 89.0% ± 1.2% was obtained for encapsulating hexyl salicylate with a hardening process by glutaraldehyde crosslinking. Micromanipulation tests revealed that gelatine-gum Arabic microcapsules exhibited typical rupture behaviours under compression. The rupture force increased with microcapsule diameter, the nominal rupture stress and toughness decreased with the increase of microcapsule size, and the nominal rupture tension was independent of diameter. The apparent Young’s modulus of whole microcapsules was determined by the Hertz model fitted to the experimental force versus displacement data. It has been found that different types of core oils significantly impacted their encapsulation efficiency, the structures of the formed microcapsules, and consequently mechanical properties.

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The oral administration of probiotics is a promising strategy to regulate the host–intestinal flora balance and improve health. Nevertheless, adverse gastrointestinal (GI) conditions affect the activity of free native probiotics. In this study, a novel probiotic encapsulation system based on milk exosomes (mExos) and DSPE-PEG-PBA was developed. mExos acted as a shield to protect probiotics from harsh GI environments, and DSPE-PEG-PBA served as a bridge between mExos and probiotics. The coated probiotics were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and intrinsic fluorescence spectra. The results showed three probiotics (Akkermansia muciniphila (AKK), Bifidobacterium animalis subsp. lactis BB-12 (BB12), and Lactiplantibacillus plantarum Q7 (Q7)) were coated with mExos@DSPE-PEG-PBA, with encapsulation rates of 90.37 ± 0.45%, 84.47 ± 1.22%, and 70.93 ± 2.39%, respectively. This encapsulation not only preserved the growth activity of the probiotics but also provided robust protection against the detrimental effects of acidic pH, bile salts, and digestive enzymes. The encapsulated strains Q7, BB12, and AKK demonstrated survival rates of 80.99 ± 0.41%, 85.28 ± 0.20%, and 94.53 ± 0.26%, respectively, in an in vitro simulated GI environment. The mExos@DSPE-PEG-PBA-encapsulated probiotics exhibited enhanced hydrophobicity and auto-aggregation capacity, accompanied by a significant improvement in mucoadhesive properties, which collectively potentiated their colonization potential within the gastrointestinal tract. These findings substantiate the potential of mExos as an encapsulation platform for probiotics, providing valuable insights into the selection of exosomes as encapsulating agents to enhance probiotic viability and mucoadhesive capacity.

Probiotics have garnered significant interest due to their diverse and vital roles in promoting intestinal health. However, several challenges continue to impede their clinical efficacy, including the preservation of bioactivity during oral administration, effective targeting of intestinal lesions, modulation of the gut microenvironment, and extension of colonization time. This review offers a comprehensive overview of biomaterial-based encapsulation strategies for targeted probiotic delivery to the intestine. Particular attention is given to the factors that govern the selection of probiotic strains and to the role of microbial interactions in shaping the design of oral delivery systems. Furthermore, we highlight the critical challenges associated with oral delivery, summarize the functional materials and their underlying mechanisms, and provide a comparative analysis of their strengths and limitations. Key factors influencing probiotic strain selection and encapsulation methods are examined in detail. The review also highlights major gastrointestinal barriers-such as variable pH, digestive enzymes, reactive oxygen species (ROS), colonization resistance, rapid transit time, and mucus layer degradation-and outlines corresponding mitigation strategies. Recent progress in targeted delivery systems and immune modulation enabled by encapsulated probiotics is discussed, along with a survey of current therapeutic applications. Finally, emerging trends and ongoing challenges in the field are explored, emphasizing the promising potential of encapsulated probiotic systems in restoring microbiome homeostasis and treating dysbiosis-related disorders.

O enhance the viability and effectiveness of Lactiplantibacillus plantarum SN13T as a probiotic, protection can be provided to the bacteria through encapsulation methods. This study aims to determine the best wall material formulation, consisting of alginate and bengkuang flour ( Pachyrhizuz erosus) , in the encapsulation process of L. plantarum SN13T. In this research, the encapsulated bacteria (beads) will be tested for their characteristics, including moisture content, bead size and morphology, total lactic acid bacteria, resistance to simulated gastric juice (SGJ) and simulated intestinal juice (SIJ), as well as encapsulation efficiency. The treatments in this study are combinations of 1% alginate wall with bengkuang flour: A = without the addition of bengkuang flour (control), B = 1% bengkuang flour, C = 3% bengkuang flour, and D = 5% bengkuang flour. The results indicate that encapsulation of L. plantarum SN13T using alginate and bengkuang flour as wall materials, specifically the use of 1% alginate + 1% bengkuang flour produces the best encapsulation results, with a moisture content of 97.34%, bead size of 2.14 mm, total lactic acid bacteria colony count of 12.88 log CFU/mL, resistance to SGJ of 95.23%, and resistance to SIJ of 95.76%. This demonstrates that encapsulation with a formulation composition of 1% alginate + 1% bengkuang flour provides optimal results for the viability and effectiveness of L. plantarum SN13T. Bengkuang flour, which contains starch, is recommended as a wall material for the encapsulation process of probiotic bacteria.

Although probiotics are widely used in the food industry due to their health-promoting effects, their application is often limited by low stability and poor viability under processing, storage, and gastrointestinal conditions. Encapsulation has emerged as a promising strategy to address these issues, offering enhanced protection and controlled release of probiotic strains. This review summarizes recent advances in encapsulation techniques relevant to food applications, including spray drying, freeze drying, coacervation, and liposome formation, as well as novel approaches such as multilayer nanocoatings and dual-core systems. The use of natural biopolymers such as alginate, chitosan, and pectin, along with food-grade synthetic materials, has greatly improved the stability of probiotics in complex food matrices. Furthermore, emerging technologies such as cell-mediated coatings offer improved resistance to gastric acid and oxygen, enhancing probiotic survival through the gastrointestinal tract. These advances contribute to the development of functional foods with better health benefits. However, challenges remain regarding scalability, strain-specific encapsulation efficiency, and regulatory approval. Future research should focus on optimizing food-grade materials, exploring synergistic effects with bioactive compounds, and ensuring consistent performance across food systems.

No abstract available

In this study, hydrogel was prepared using soy hull polysaccharides (SHP) and soy protein isolate (SPI) as matrices, while oleogel was formulated from soy lecithin (SL) and stearic acid (SA). Bigels with varying oil-to-water ratios (O:H 3:7, 5:5, 7:3) were fabricated and characterized. The O:H 5:5 bigels exhibited the most favorable properties, including superior viscoelasticity, thermal stability, and liquid-holding capacity, together with a uniform and compact microstructure. Encapsulation studies demonstrated that loading Lactiplantibacillus plantarum into the oil phase of the O:H 5:5 bigels achieved the highest encapsulation efficiency (90.3%) and sustained viable counts of 5.47 × 109 CFU/g after 4 weeks of storage. Compared with free probiotics, encapsulated cells displayed markedly enhanced tolerance during in vitro simulated digestion, with survival rates exceeding 87% under gastric conditions and remaining above 60% following intestinal digestion. These findings highlight the potential of soybean-based bigels as an effective carrier for probiotic delivery.

In this study, Lacticaseibacillus paracasei probiotic bacteria were encapsulated by freeze-drying (lyophilization) method using three different parts of chestnut fruit: kernel, inner, and outer shell. The encapsulation efficiencies of Lacticaseibacillus paracasei probiotic bacteria were determined as 85.76±0.12%, 81.21±0.02%, and 79.38±0.05%, respectively. FTIR and SEM characterized the structure and surface of the capsules. In addition, the viability of free and encapsulated bacteria was analyzed during in vitro gastrointestinal digestion conditions. During in vitro gastrointestinal digestion, free bacteria lost their viability at 90 min of gastric digestion, while encapsulated probiotic bacteria were able to reach the intestinal environment. Thus, it is envisaged that new products can be developed by using Lacticaseibacillus paracasei loaded capsules as a natural additive in food products.

Probiotics suffer low viability from heat and oxidative stress during spray drying. This study evaluated alkaline-pH-shifted mung bean protein isolate (pHMBPI) as an encapsulant for Limosilactobacillus reuteri KUB-AC5, compared with mung bean protein isolate (MBPI) and whey protein isolate (WPI). pHMBPI showed the highest solubility (82.66%), surface hydrophobicity (3574), and ABTS•+ scavenging activity (91.62%). pHMBPI-spray-dried cells had the lowest cell wall (25.31%) and membrane injury (10.22%), the highest viable count (1.49 × 109 CFU/g) and survival (9.91%). Viability during digestion remained high (8.60 and 8.05 log CFU/g in gastric and intestinal fluids). NMR confirmed reduced lipid peroxidation, preserving 85.2% of bis-allylic protons. Molecular dynamics simulations revealed strong electrostatic interactions between 8S-alpha globulin and cell wall targets, including peptidoglycan, Mub-RV, and SRRP53608. These results identify pHMBPI as a promising encapsulant offering enhanced thermal stability, antioxidant defense, and targeted bacterial surface binding.

Probiotics offer diverse health benefits, but their efficacy is compromised by gastrointestinal stress and burst release in conventional encapsulation systems, limiting the efficacy of probiotics in functional foods. Herein, an alginate-coated cellulose roll capsule with anisotropic porous structures and sustained release property was developed via a combined strategy of directional freeze casting and ethanol coagulation bath, which avoids the need for energy-intensive freeze-drying. The pH-responsive alginate shell and layered cellulose roll core synergistically blocked acidic penetration and enhanced probiotic survival in the gastric environment, while the gradual dissolution of alginate shell and unfolding of cellulose roll led to controlled release of probiotics from the aligned microchannels in the intestinal environment. The design endowed the capsule with excellent survival rate (91.03%), high release count (1.82 × 108 CFU), prolonged release duration (9 h) and zero-order release kinetics. This study is based on in vitro simulated digestion using a single probiotic strain, and future work will address in vivo validation with additional probiotic species. This bioinspired system provides a strategy for functional food delivery by addressing the burst release challenge of probiotic encapsulation.

This study presents a novel dual cross-linking method using Prunus mume concentrate (PMC) as a source of H+ and Ca2+ to enhance polysaccharide (sodium alginate/carboxymethyl chitosan/gelatin) microcapsule formation. The structure and release characteristics of microcapsules were influenced more by PMC pH than by its concentration. SEM results showed that as the pH decreased, the microcapsules had a more compact structure. The FTIR results showed that acid enhances hydrogen bonding and electrostatic interactions within the polysaccharide, leading to more stable microcapsule structures. XRD patterns showed that acid enhanced the stability of the polysaccharide crystal structure. Microcapsules significantly increased viable counts by 1 log(CFU/mL) in simulated gastric fluid (SGF) and 1.25 log(CFU/mL) in simulated intestinal fluid (SIF) after 3 h of digestion. This study provides a basis for investigating the dual cross-linking of natural plant concentrates and Ca2+ construction of polysaccharide microcapsules to enhance probiotic resistance.

No abstract available

Probiotic-based bacteriotherapies show promise for treating inflammatory bowel disease (IBD) by dynamically modulating the intestinal microenvironment. However, their clinical efficacy is hampered by poor gastrointestinal viability, limited intestinal retention, and low bioactivity. To overcome these challenges, we developed a prodrug-integrated multifunctional liposomal coating strategy to enhance probiotic efficacy. This liposomal coating protects probiotics from gastric acid, significantly improving their viability after oral administration. In the acidic stomach environment, protonation of amine groups on the liposomal surface increases the surface positive charge, enhancing probiotic adhesion to the negatively charged intestinal mucus through weakening electrostatic repulsion. Concurrently, PEG2000 chains further promote deep mucus penetration, facilitating enhanced colonization, prolonged intestinal retention, and reinforcement of epithelial barrier function. Additionally, idebenone (IDE), conjugated to the liposomal surface via a ROS-responsive linker, is selectively released in inflamed regions with elevated ROS levels, providing localized antioxidant and anti-inflammatory effects. In multiple colitis models, this engineered probiotic platform demonstrated significant prophylactic and therapeutic efficacy with favorable safety profiles, highlighting its potential as an effective strategy for IBD therapy.

No abstract available

In this study, starch-based nanofiber mats were successfully prepared from aqueous solution by electrospinning and used for probiotic encapsulation for the first time. The physicochemical properties of the octenylsuccinated (OS) starch/poly(vinyl alcohol) (PVA) blend solutions were systematically investigated. Through Fourier transform infrared spectroscopy and X-ray diffraction spectra analysis, it was found that miscibility and hydrogen bonding interactions exist between OS starch and PVA molecules. Thermogravimetric analysis and derivative thermogravimetric analysis revealed that the produced nanofibers possess satisfactory thermal stability. Scanning electron microscopy images and diameter distribution histograms showed that continuous and defect-free nanofibers were obtained and along with the increase in the weight ratio of OS starch, the average diameter gradually decreased. In addition, it was confirmed that the probiotics were successfully encapsulated in nanofiber mats. The survival rates of Lactobacillus plantarum AB-1 and Lactobacillus rhamnosus GG encapsulated in nanofibers were as high as 94.63% and 92.42%, respectively, significantly higher than those of traditional freeze-drying. Moreover, compared to free cells, probiotics encapsulated in nanofiber mats retained better viability after 21 days of storage at 4 and 25°C, and showed remarkably higher survival rates after exposure to simulated gastric and intestinal fluid. This study showed that the developed nanofibers can be a promising encapsulation system for the protection of probiotics.

No abstract available

Calcium alginate hydrogel beads are spherical polymeric particles with highly crosslinked network structures, known for their excellent monodispersity and retention capabilities. These beads, produced by high‐throughput droplet‐based microfluidic techniques, are widely used for encapsulating and cultivating various microscopic particles such as cells. While internal gelation has been commonly utilized for crosslinking of calcium alginate hydrogel beads in microalgae encapsulation, the use of external gelation remains underexplored. This study utilized droplet‐based microfluidic technology combined with external gelation to produce calcium alginate hydrogel beads for encapsulating the microalgal strain Chlorella vulgaris. Emulsions containing emulsified calcium ions served as the crosslinking phase. Initial geometrical analysis indicated that beads crosslinked with a high concentration of calcium ions (1 g/mL) achieve superior size uniformity and shape consistency. Microalgae cultivation experiments using these beads demonstrated steady growth of Chlorella vulgaris over a 5‐day period, with the beads maintaining their geometric stability until the final day when minor cell leakage was observed. These results provide a foundation for future molecular‐level studies on microalgae cultivation in hydrogel beads and suggest potential applications in fields requiring precisely controlled microalgae growth.

Small interfering RNAs (siRNAs) have brought revolutionary advances as promising therapeutic candidates for ulcerative colitis, owing to the durable anti-inflammatory efficacy and favorable biocompatibility. Nevertheless, the clinical translation of oral siRNA therapeutics remains hindered by the harsh conditions of the gastrointestinal tract. Thus, a colon-specific modular hydrogel platform (IG@SP@FK LNPs@siTNFα) was engineered through integration of microalgal biotechnology and nanomedicines. The system comprised three functionally components: (i) a cathepsin B/glutathione (GSH) dual-responsive gemini-like cationic MA-FK-SS lipid nanoparticles core encapsulating tumor necrosis factor-α siRNA (FK LNPs@siTNFα); (ii) a negatively charged Spirulina (SP) intermediate layer (SP@FK LNPs@siTNFα); and (iii) an outer inulin-derived hydrogel (IG) coating. The IG layer provided robust protection against harsh gastrointestinal conditions and regulated the gut microbiota homeostasis. Subsequent colonic degradation of IG triggered site-specific release of SP@FK LNPs@siTNFα, which exhibited enhanced mucosal adhesion through the intrinsic helical architecture of SP. Notably, FK LNPs@siTNFα demonstrated efficient cellular internalization, proton-sponge effect-driven endosomal escape and dual-responsive siRNA release, ultimately silencing the expression of TNF-α. IG@SP@FK LNPs@siTNFα significantly attenuated the progression of ulcerative colitis via suppression of pro-inflammatory cytokine cascades (IL-6, IL-1β, TNF-α), restoration of intestinal barrier integrity, and normalization of gut microbiota homeostasis. This nano-biohybrid system established a paradigm for oral nucleic acid delivery, combining spatiotemporal control and multi-mechanistic intervention for precise gene therapy of ulcerative colitis.

Encapsulation of microalgae in hydrogel beads is a highly effective method for high‐yield microalgae cultivation. Emerging microfluidics‐based droplet generation techniques enable the miniaturization of the microalgae‐bead system. This provides enhanced control over encapsulation, precise droplet size manipulation, and the ability to study cell growth dynamics at the microscale. This paper explores the growth behavior and survivability of microalgae encapsulated in calcium alginate hydrogel micro beads, along with the structural stability of the beads in various solutions. The solutions under investigation were pure BG‐11 growth medium, copper ion solutions, and their mixtures. Encapsulated microalgae exhibited steady growth in BG‐11 medium, with the highest growth at a 1:50 dilution ratio. Exposure to copper ions, particularly at higher concentrations, adversely affected cell growth and viability. No major structural degradation occurred in hydrogel beads across all growth conditions. Additionally, we conducted short‐term storage followed by regrowth experiments to evaluate the resilience and recovery potential of encapsulated microalgae. The results indicated that microalgae remained viable and slowly proliferated during storage, although cell clustering at the end of storage impacted regrowth efficiency. During storage, we observed noticeable increases in bead size and shape changes. However, minimal geometric alterations occurred during the subsequent regrowth phase.

Ellagic acid (EA), a naturally occurring bioactive phenolic compound largely found in pomegranate, exhibits significant health benefits due to its antioxidant, antimutagenic, and even anticancerogenic properties. The present work aimed to microencapsulate EA extracted from pomegranate peels. To improve the stability of EA, microencapsulation was applied with Spirulina as a coating material. For this purpose, ethanolic extracts obtained from pomegranate peels were used for microencapsulation. Response surface methodology combined with a three-level, three-variable Box-Behnken design (BBD) was applied to obtain optimum microencapsulation. The microparticles obtained under the optimized encapsulation conditions were further characterized by FT-IR and SEM. The results confirmed the encapsulation of EA in Spirulina cells. Then, the optimum microparticles were used in an in vitro release study. The results of the in vitro digestion with simulated gastrointestinal fluids could help to determine the content and biological activity of EA. In this study, the effect of encapsulation on the release properties of EA during simulated gastrointestinal digestion was also evaluated. HPLC-DAD analysis and the Folin-Ciocalteu and ABTS methods were helpful for characterization of EA in the simulated fluids. The release profile of EA indicated that in simulated intestinal fluid, the release was faster than that in gastric fluid. PRACTICAL APPLICATION: This study describes the microencapsulation of ethanolic extracts of pomegranate peel (PP) in Spirulina. This application has been performed to improve the stability and bioavailability of EA in the extracts. Optimum microencapsulation was obtained by response surface methodology with BBD. After the characterization of the obtained optimum Spirulina/EA mixture by FT-IR and SEM, an in vitro release study was conducted for stability research. The results will guide other researchers working on the determination of the content and biological activity of EA and on optimizing the microencapsulation process.

No abstract available

This paper introduces an enzymatic approach to estimate internal mass-transfer resistances during food digestion studies. Cellulase has been used to degrade starch cell walls (where cellulose is a significant component) and reduce the internal mass-transfer resistance, so that the starch granules are released and hydrolysed by amylase, increasing the starch hydrolysis rates, as a technique for measuring the internal mass-transfer resistance of cell walls. The estimated internal mass-transfer resistances for granular starch hydrolysis in a beaker and stirrer system for simulating the food digestion range from 2.2 × 107 m−1 s at a stirrer speed of 100 rpm to 6.6 × 107 m−1 s at 200 rpm. The reaction rate constants for cellulase-treated starch are about three to eight times as great as those for starch powder. The beaker and stirrer system provides an in vitro model to quantitatively understand external mass-transfer resistance and compare mass-transfer and reaction rate kinetics in starch hydrolysis during food digestion. Particle size analysis indicates that starch cell wall degradation reduces starch granule adhesion (compared with soaked starch samples), though the primary particle sizes are similar, and increases the interfacial surface area, reducing internal mass-transfer resistance and overall mass-transfer resistance. Dimensional analysis (such as the Damköhler numbers, Da, 0.3–0.5) from this in vitro system shows that mass-transfer rates are greater than reaction rates. At the same time, SEM (scanning electron microscopy) images of starch particles indicate significant morphology changes due to the cell wall degradation.

Arsenic (As) pollution seriously threatens human and ecological health. Microalgal cell wall and extracellular polymeric substances (EPS) are known to interact with As, but their roles in the As resistance, accumulation and speciation in microalgae remain unclear. Here, we used two strains of Chlamydomonas reinhardtii, namely CC-125 (wild type) and CC-503 (cell wall-deficient mutant), to examine the algal growth, EPS synthesis, As adsorption, absorption and transformation under 10-1000 µg/L As(III) and As(V) treatments for 96 h. In both strains, the As absorption increased after the EPS removal, but the growth, As adsorption, and transformation of C. reinhardtii declined. The CC-125 strain was more tolerant to As stress and more efficient in EPS production, As accumulation, and redox transformation than CC-503, irrespective of EPS presence or absence. Three-dimension excitation-emission matrix (3D-EEM) and attenuated total reflectance infrared spectroscopy (ATR-IR) analyses showed that As was bound with functional groups in the EPS and cell wall, such as -COOH, NH and -OH in proteins, polysaccharides and amino acids. Together, this study demonstrated that EPS and cell wall acted as barriers to lower the As uptake by C. reinhardtii. However, the cell wall mutant strain was more susceptible to As toxicity due to lower EPS induction and higher As absorption.

Mycoprotein, with a balanced amino acid profile and potential benefits for muscle maintenance, is a promising protein source for elderly-friendly high-protein foods. Yet, rigid fungal cell walls and entangled hyphal networks enclosing intracellular proteins may restrict enzymatic accessibility under elderly digestive conditions. In this study, high-pressure homogenization (HPH) was applied as a food-grade structural regulation strategy to improve the digestive adaptability of mycoprotein. Native mycoprotein (MYC), HPH-treated mycoprotein (HMYC), pork (PORK), and commercial plant-based meat (PLANT) were evaluated using a static in vitro oral-gastric-intestinal digestion model simulating elderly physiological conditions. Structural disintegration, hydrolysis behavior, free amino acid release, multiple light scattering, and microrheological properties were analyzed to elucidate digestive adaptation mechanisms. HPH markedly disrupted the cell-wall-associated and hypha-entangled structure of mycoprotein without significantly altering its major nutrient composition, thereby improving enzyme accessibility and digestion-induced disintegration. During gastric and intestinal digestion, the particle size D[4,3] of HMYC decreased by over 80%, indicating enhanced structural breakdown efficiency. HMYC exhibited a significantly higher hydrolysis degree than MYC, while its free amino acid release approached that of PORK and exceeded those of both MYC and PLANT. Multiple light scattering revealed improved enzyme-substrate interaction and greater physical structural transformation after HPH treatment. Microrheological analysis further confirmed improved restructuring behavior and reduced structural resistance during digestion. Overall, HPH effectively improved the digestive adaptability of mycoprotein under elderly digestive conditions, making its digestive behavior closer to that of PORK, while the distinct digestion behavior of PLANT was mainly associated with matrix effects from added lipids and hydrocolloids, supporting the development of elderly-friendly mycoprotein-based foods.

Antibodies against the Plasmodium falciparum circumsporozoite protein (PfCSP) can block hepatocyte infection by sporozoites and protect against malaria. Needle-free vaccination strategies are desirable, yet most PfCSP-targeted vaccines like RTS,S require needle-based administration. Here, we evaluated the edible algae, Arthrospira platensis (commonly called ‘spirulina’) as a malaria vaccine platform. Spirulina were genetically engineered to express virus-like particles (VLPs) consisting of the woodchuck hepatitis B core capsid protein (WHcAg) displaying a (NANP)15 PfCSP antigen on its surface. PfCSP-spirulina administered to mice intranasally followed by oral PfCSP-spirulina boosters resulted in a strong, systemic anti-PfCSP immune response that was protective against subcutaneous challenge with PfCSP-expressing P. yoelii. Unlike male mice, female mice did not require Montanide adjuvant to reach high antibody titers or protection. The successful use of spirulina as a vaccine delivery system warrants further development of spirulina-based vaccines as a useful tool in addressing malaria and other diseases of global health importance.

Protecting the whole small intestine from radiation-induced intestinal injury during the radiotherapy of abdominal or pelvic solid tumors remains an unmet clinical need. Amifostine is a promising selective radioprotector for normal tissues. However, its oral application in intestinal radioprotection remains challenging. Herein, we use microalga Spirulina platensis as a microcarrier of Amifostine to construct an oral delivery system. The system shows comprehensive drug accumulation and effective radioprotection in the whole small intestine that is significantly superior to free drug and its enteric capsule, preventing the radiation-induced intestine injury and prolonging the survival without influencing the tumor regression. It also shows benefits on the gut microbiota homeostasis and long-term safety. Based on a readily available natural microcarrier, this work presents a convenient oral delivery system to achieve effective radioprotection for the whole small intestine, providing a competitive strategy with great clinical translation potential. Protecting the whole small intestine from radiation-induced intestinal injury during the radiotherapy of abdominal or pelvic solid tumors remains an unmet clinical need. Here the authors use a natural microalga to readily construct an oral delivery system to achieve effective radioprotection for the small intestine.

Ulcerative colitis (UC) is associated with epithelial barrier disruption, oxidative stress, inflammation, and gut microbiota dysbiosis. Oral colon-localized delivery remains challenging because therapeutic cargos must resist gastric exposure, avoid premature release, be retained at inflamed colonic sites, and respond to pathological microenvironments. Herein, a pH/reactive oxygen species (ROS) dual-responsive calcium alginate microalgal hydrogel, denoted SP@GaTa@ALG (SGA), was developed for localized UC therapy. Gallium-tannic acid nanoparticles (GaTa NPs) were loaded onto Spirulina (SP) and encapsulated within a Ca2+-crosslinked alginate matrix. The calcium alginate network provided gastric protection and pH-dependent control over Ga3+ diffusion, while GaTa enabled ROS-responsive Ga3+ release and antioxidant activity. In vitro, SGA scavenged free radicals, reduced intracellular ROS accumulation, protected epithelial cells against H2O2-induced injury, preserved mitochondrial membrane potential, and promoted an anti-inflammatory-like macrophage phenotype. After oral administration, SGA showed prolonged gastrointestinal retention and enhanced colonic localization compared with non-encapsulated SP@GaTa (SG). In dextran sulfate sodium (DSS)-induced colitis mice, SGA alleviated body-weight loss, reduced disease activity, restored colon length, improved zonula occludens-1 (ZO-1) and Occludin expression, suppressed inflammatory mediators, and was associated with gut microbiota remodeling. These findings support SGA as a traceable, carbohydrate-polymer-based oral platform for inflammation-responsive UC intervention.

Irritable bowel syndrome (IBS) is a prevalent gastrointestinal disorder characterized by mental manifestations, abdominal pain, and alterations in defecation habits. The incidence rate in some areas even exceeds 20%. Secondary to chronic, recurrent gastrointestinal motility dysfunction, for patients with IBS, upon oral administration of drugs, the fluctuation of bioavailability is typically far more significant than that of healthy individuals. Nevertheless, at present, few studies have put forward targeted drug delivery systems addressing this aspect. In this study, an oral spirulina nanotechnology System (SP@TIIAn) is developed that integrates tanshinone IIA liposome with spirulina for enhanced IBS treatment. Owing to the passive targeting of intestinal villi and enhanced adhesion by spirulina and nanoparticles, it is discovered that, in contrast to enteric‐coated capsules, this system is more beneficial for guaranteeing the pharmacokinetic stability of IBS. SP@TIIAn effectively treats multiple gut‐brain symptoms of IBS, contributing to providing new alternatives for the development of clinical medications for IBS.

The use of the edible photosynthetic cyanobacterium Arthrospira platensis (spirulina) as a biomanufacturing platform has been limited by a lack of genetic tools. Here we report genetic engineering methods for stable, high-level expression of bioactive proteins in spirulina, including large-scale, indoor cultivation and downstream processing methods. Following targeted integration of exogenous genes into the spirulina chromosome (chr), encoded protein biopharmaceuticals can represent as much as 15% of total biomass, require no purification before oral delivery and are stable without refrigeration and protected during gastric transit when encapsulated within dry spirulina. Oral delivery of a spirulina-expressed antibody targeting campylobacter—a major cause of infant mortality in the developing world—prevents disease in mice, and a phase 1 clinical trial demonstrated safety for human administration. Spirulina provides an advantageous system for the manufacture of orally delivered therapeutic proteins by combining the safety of a food-based production host with the accessible genetic manipulation and high productivity of microbial platforms. Spirulina is used to manufacture a therapeutic antibody against campylobacter.

Oral administration remains the preferred route for therapeutics due to its non-invasiveness and high patient compliance. However, its application for biologics (e.g., peptides, proteins, nucleic acids) and some small-molecule drugs is severely constrained by multifaceted gastrointestinal (GI) barriers. These barriers include chemical degradation, mucus entrapment, epithelial impermeability, first-pass metabolism, and gut microbiota interactions, which severely limit the oral bioavailability of most therapeutics. Engineered nanomaterials have emerged as revolutionary platforms, leveraging tunable physicochemical properties and bioresponsive functionalities to sequentially overcome GI barriers. Advanced systems using lipid-based, polymer-based, inorganic, and hybrid nanomaterials synergize sequential barrier evasion through integrated protection, mucus penetration, and receptor-targeted transcytosis. Despite preclinical success, challenges in rational material design, precise construction and safety concerns hinder their clinical translation. This review comprehensively analyzes the interplay between nanomaterial engineering and GI barrier evasion, providing a roadmap for advancing precision oral therapeutics from bench to bedside.

Oxidative stress, overproduction of reactive oxygen species (ROS), plays an important role in the development of inflammatory bowel diseases. Catalase has great therapeutic potential by scavenging hydrogen peroxide, one of the ROSs produced in cellular metabolisms. However, in vivo application to scavenge ROS is currently limited especially in oral administrations. Here, we introduced an alginate-based oral drug delivery system that effectively protected catalase from the simulated harsh conditions of the gastrointestinal (GI) tract, released it in the small intestine mimicked condition, and enhanced its absorption via M cells, highly specialized epithelium cells in the small intestine. First of all, catalase was encapsulated in alginate-based microparticles with different amounts of polygalacturonic acid or pectin, which achieved an encapsulation efficiency of more than 90%. It was further shown that catalase was released from alginate-based microparticles in a pH-dependent manner. Results indicated that alginate-polygalacturonic acid microparticles (60 wt % Alg:40 wt % Gal) released 79.5 ± 2.4% of encapsulated catalase at pH 9.1 in 3 h, while they only released 9.2 ± 1.5% of encapsulated catalase at pH 2.0. Even when catalase was encapsulated in microparticles (60 wt % Alg:40 wt % Gal) and exposed to pH 2.0 followed by pH 9.1, it still retained 81.0 ± 11.3% enzyme activity compared to that in microparticles prior to the pH treatment. We then investigated the efficiency of RGD conjugation to catalase on the catalase uptake by M-like cells, the coculturing of human epithelial colorectal adenocarcinoma; Caco-2 cells and B lymphocyte; Raji cells. RGD-catalase protected M-cells more efficiently from the cytotoxicity of H2O2, a typical ROS. RGD conjugation to catalase enhanced the uptake by M-cells with 87.6 ± 0.8% RGD-catalase, whereas 11.5 ± 9.2% of RGD-free catalase passed across M-cells. From the results of protection, release, and absorption of model therapeutic proteins from the harsh pH conditions, alginate-based oral drug delivery systems will have numerous applications for the controlled release of drugs that are easily degradable in the GI tract.

Oral drug delivery has always been the preferred route for patients and physicians alike. However, the oral route presents several challenges, including low permeability and uptake, particularly for therapeutic proteins, with insulin being a prime example. Oral insulin barely reaches the bloodstream as it is digested and breaks down due to the enzymatic environment and its inability to transverse the gut barrier due to its molecular weight. To the best of our knowledge, this is the first report to investigate the potential of genetically engineered (GE) Arthrospira platensis (i.e., Spirulina) as an oral carrier of human insulin (hINS), as well as the intestinal uptake of recombinant hINS produced by GE Spirulina. Furthermore, we report for the first time the application of acetosyringone (ACE) and salicylic acid (SA) to GE Spirulina to enhance hINS production. This study examines the potential of GE Spirulina as an oral delivery vehicle. Agrobacterium containing a pCAMBIA-based binary vector with the hINS gene in its transfer-DNA (T-DNA) segment was used to transform Spirulina via the co-cultivation method. Acetosyringone (ACE) was investigated for its effect on transformation efficiency, and salicylic acid (SA) was investigated for its ability to increase hINS production. The production of hINS was quantified using the hINS ELISA kit. Furthermore, we investigated the scalability potential of this method using laboratory-scale batch bioreactors. Lastly, the potential of engineered Spirulina to deliver hINS was assessed via intestinal uptake and permeability experiments using rat tissues. Colony-PCR confirmed the presence of pCAMBIA-based plasmid in Agrobacterium tumefaciens GV3101 (used to transform Spirulina). Spirulina was found to be sensitive to hygromycin and cefotaxime antibiotics, enabling the harvesting and separation of transformed Spirulina. The PCR amplification of hINS from genomic DNA indicated stable integration into the Spirulina genome, consistent with previous reports; however, additional junction-level confirmation is recommended. Adding 200 µM ACE during the transformation process increased transfection and hINS production compared to the control (2.3 ± 0.15 ng vs. 0.9 ± 0.31 ng, respectively). A second round of transformation increased hINS production while a third transfection cycle reduced it. The addition of 100 µM SA increased hINS production by 2.9-fold. Interestingly, scaled-up production of genetically engineered (GE) Spirulina using a 2 L glass bioreactor resulted in 277% higher hINS production than expected based on volume increase. The hINS produced by GE Spirulina is bioactive, is released intact, and remains stable under intestinal conditions. Ex vivo experiments with the small intestines of rats exposed to GE Spirulina revealed that hINS was uptaken in the rat's ileum > jejunum > duodenum. In contrast, transverse accumulation of the hINS was the highest for the duodenum, followed by the jejunum and ileum. The results of this study demonstrate the potential of GE Spirulina as an effective oral drug carrier, warranting further exploration.

Introduction Oral delivery of peptides is a promising alternative to invasive injectable therapies, offering improved patient adherence and convenience. Glucagon-like peptide-1 (GLP-1) analogs, in particular, are highly effective for the management of type 2 diabetes mellitus and obesity, yet their oral bioavailability remains limited by enzymatic degradation and poor intestinal permeability. Methods In this study, we aimed to design a lipid-based formulation (LBF) of the model GLP-1 analog exenatide (EXE) in its hydrophobic ion-paired (HIP) form, incorporating permeation-enhancing excipients, and evaluate its performance in enteric capsule systems. Results and discussion EXE-HIP was prepared with sodium docusate (1:4 molar ratio), which increased lipophilicity (log P = 0.9 ± 0.2 vs. −2.9 ± 0.3 for EXE) and markedly improved solubility in lipid excipients, especially in Labrafac™ MC60, a known promoter of intestinal permeability. An optimized LBF composed of 85% Labrafac™ MC60, 10% Kolliphor® RH40, and 5% propylene glycol was developed, with a final particle size of 106 nm, and it was loaded with 6 mg/g solubilized EXE (HIP form) and 20 mg/g of sodium caprate (complementary permeation enhancer). The formulation exhibited significant protection against α-chymotrypsin-mediated degradation, which is consistent with sequestration of EXE-HIP within lipid droplets that limit enzymatic access. Short-term stability studies highlighted formulation-dependent degradation behavior, with higher impurity formation observed for solubilized EXE-HIP than for suspended EXE acetate, particularly at room temperature. To further support oral delivery, customized gelatin/HPMC-AS enteric capsules were engineered to provide a complementary two-tier protection strategy: (i) protecting the peptide and lipid phase from gastric enzymatic degradation and preventing premature dilution in gastric fluids that could displace the peptide from its protective lipid environment, while (ii) ensuring coordinated release of both EXE-HIP and the permeation enhancers at the intestinal absorption site. These capsules met the USP delayed release requirements. Overall, this work presents a promising proof-of-concept oral delivery platform that combines HIP chemistry, lipid-based formulation, and ready-to-use enteric capsule technology to enhance in vitro enzymatic protection of peptide therapeutics, thereby laying the groundwork for future studies to assess bioavailability and therapeutic efficacy in vivo.

Peptide and protein (PP) therapeutics are highly specific and potent biomolecules that treat chronic and complex diseases. However, their oral delivery is significantly hindered by enzymatic degradation, instability, and poor permeability through the gastrointestinal (GI) epithelium, resulting in low bioavailability. Various strategies have emerged as transformative solutions to address existing challenges, offering enhanced protection, stabilization, and absorption of PPs. These strategies primarily focus on two major challenges: protecting the PP against harsh conditions and enhancing permeation across the intestinal membrane. Innovative approaches such as pH modulation and incorporation of enzyme inhibitors are usually used to mitigate proteolytic degradation of PP during transit across the GI tract. In a similar vein, absorption enhancers and prodrug strategies facilitate epithelial transport, while targeted delivery systems focus on specific areas of the GI tract to enhance absorption. Likewise, mucus-penetrating and mucoadhesive strategies have enhanced retention and interaction with epithelial cells, effectively overcoming barriers like the mucus layer and tight epithelial junctions. Furthermore, structural modifications such as lipidation, peptide cyclization, and polyethylene glycosylation are promising alternatives to render stability, prolong circulation time, and membrane permeability. In particular, functional biomaterials, active targeting, and lymphatic transport strategies have provided new platforms for oral PP delivery. Advancing in materials science, nanotechnology, and the disruption of medical devices holds new frontiers to overcome barriers. Despite substantial advancements, the limited success in clinical translation underscores the urgency of innovative strategies. This review presents oral PPs as a promising platform, highlighting the key barriers and strategies to transform their therapeutic landscapes.

Bacterium-like particles (BLPs) have gained significant attention in vaccine development due to their potential as effective immune enhancers and antigen delivery systems. BLPs are generated by boiling lactic acid bacteria in an acidic solution and are devoid of proteins and nucleic acids, offering advantages in terms of ease of preparation, high safety, and good stability. Furthermore, by employing protein anchor (PA), heterogeneous antigens can be efficiently displayed on the surface of BLPs, resulting in enhanced delivery effectiveness. Despite these benefits, most BLP-based vaccines are currently administered via injection or intranasal delivery, with oral delivery remaining limited. This limitation is primarily due to the harsh environment of the gastrointestinal tract, which degrades the antigens displayed on the surface of these particles. To enhance the efficacy of oral immunization with subunit vaccines, we developed a simple and rapid method for self-assembling a lipid membrane onto the surface of BLPs vaccines, achieving an encapsulation efficiency of up to 99%, and the combination has good biosafety. The novel oral delivery system not only preserves the adjuvant activity of BLPs but also efficiently protects antigens from adverse gastrointestinal environments, increasing the absorption of the vaccine in intestinal Peyer’s patches (PPs). Oral immunization was required only once, and protection after the challenge was up to 100%. Furthermore, we observed rapid immunity and cross-protection. Transcriptome analysis of the small intestine suggested that immune enhancement probably be exerted by promoting the absorption and transport of antigens. Therefore, we posit that the design of this new oral delivery system presents a novel approach to advancing the development of oral subunit vaccines.

Bacteriophage therapy can successfully provide additional treatment to control Salmonella infection, but low gastric pH limits its oral application. The present study aimed to develop an improved encapsulation formulation with enhanced acid protection for oral delivery of Salmonella phages using polymers. This was achieved by encapsulating a phage cocktail containing three different bacteriophages against Salmonella sp. in alginate beads incorporating polyvinyl alcohol (PVA), PVP-K30, and calcium carbonate as viscosity modifiers and acid protection enhancers. Further, the beads were coated with poly-L-lysine to improve the stability and tested for their efficacy for improved phage viability under in vitro acidic conditions for subsequent use in oral delivery. Moist beads were slimy, and semi-dried beads presented a coarse surface as observed using FE-SEM. In vitro studies revealed that the free phage cocktail exhibited complete inactivation when exposed to acidic pH 2.5 after 15 min incubation. In contrast, the encapsulated phage cocktail showed a decrease of only 1.66 log units in viability when incubated for 90 min at pH 2.5. Furthermore, oral delivery of the encapsulated phage cocktail in the poultry model significantly reduced bacterial load in infected birds’ intestines.