bims-livmat 2025-07-27 papers

bims-livmat

Biomed News

on Living materials

Issue of 2025–07–27
seven papers selected by
Sara Trujillo Muñoz, Leibniz-Institut für Neue Materialien

Genetic "expiry-date" circuits control lifespan of synthetic scavenger bacteria for safe bioremediation.
Engineered Probiotic Hydrogel Alleviates Vaginitis via Antimicrobial and Anti-inflammatory Pathways.
Sonogenetics regulation of intelligent engineered bacteria to reverse immune escape.
Viability Preservation of Probiotic Bacteria Encapsulated in Pectin-Reinforced pH-Responsive Composite Alginate Hydrogel Matrix as the Synbiotic Delivery System.
Advanced chitosan-based biopolymer systems for probiotic microencapsulation: stability enhancement and targeted release approaches.
Alginate/Arabic gum-chitosan-encapsulated Bacillus subtilis enhances probiotic viability and alleviates liver injury and fibrosis in cholestatic rats.
Amelioration of Colitis Using Colonic Microbiota-Stimulated Release of Tributyrin from Pickering Emulsion-Filled Alginate Beads.

Nucleic Acids Res. 2025 Jul 19. pii: gkaf703. [Epub ahead of print]53(14):

Genetic "expiry-date" circuits control lifespan of synthetic scavenger bacteria for safe bioremediation.

Kha Mong Tran, Nuong Thi Nong, Jun Ren, Kangseok Lee, Doheon Lee, Jörg Gsponer, Hyang-Mi Lee, Dokyun Na.

Synthetic biology enabled the systematic engineering of bacteria for diverse applications, but their deployment in open environments raises concerns about their persistence and unintended ecological impacts. To address these challenges, genetic "expiry-date" circuits were designed to impose a tunable lifespan on bacteria. These circuits, structured as a feedforward activation network, regulate the timing of cell death by controlling the expression of Lysis E, enabling a programmed lifespan ranging from hours to days. The lifespan can be tailored by modifying the number of activation steps in the cascade. The circuits were optimized by reducing gene expression leakiness of Lysis E using a synthetic small regulatory RNA and combining it with an asd-based auxotrophic system. The bacteria harboring the "expiry-date" circuits resulted in a GMO escape rate below U.S. NIH release standards (<10-10). To validate the practical applicability of this system, a synthetic phenol-scavenging Escherichia coli was constructed, which possessed enhanced phenol tolerance and phenol-detoxification capability, and harbored the "expiry-date" circuits. The engineered bacteria detoxified 0.1 g/kg of phenol in soil within 4 days and self-destructed by day 5. These results support the circuit's potential as a biocontainment strategy for the safe and controlled deployment of synthetic bacteria in real-world applications.

DOI: https://doi.org/10.1093/nar/gkaf703
ACS Appl Bio Mater. 2025 Jul 24.

Engineered Probiotic Hydrogel Alleviates Vaginitis via Antimicrobial and Anti-inflammatory Pathways.

Xuanxuan Zhang, Ruoyu Pu, Chi Zhang, Mengyi Zhan, Li Chen, Lixin Ma, Huanhuan Chen.

  Vulvovaginal candidiasis (VVC), primarily caused by Candida albicans, is a prevalent infection that presents significant clinical challenges. Current antifungal treatments have limitations, including a narrow antimicrobial spectrum and a lack of anti-inflammatory effects. To address these limitations, we genetically modified Bacillus subtilis to produce high-molecular-weight hyaluronic acid (HMHA) for sustained local delivery of antimicrobial peptides (AMP) and HMHA at the infection site. The engineered Bacillus subtilis (B. sub@HMHA) hydrogel exhibited both antifungal and vaginal microbiome-modulating activities. Specifically, AMP effectively inhibited the growth of fungi and bacteria, while HMHA modulated local inflammatory responses, improving the vaginal microenvironment. By targeting both the infection and chronic inflammation, this probiotic hydrogel may help reduce recurrence rates and promote tissue repair, offering a promising alternative therapy for VVC.

Keywords:  Bacillus subtilis; Candida vaginitis; antimicrobial peptides; engineered probiotic; high-molecular-weight hyaluronic acid

DOI:  https://doi.org/10.1021/acsabm.5c00766
Mater Today Bio. 2025 Aug;33 102043

Sonogenetics regulation of intelligent engineered bacteria to reverse immune escape.

Ru Jiang, Beibei Zhang, Shaobo Duan, Yaqiong Li, Yuzhou Wang, Yongchao Wang, Juan Zhang, Rong Huang, Rui Zhang, Qi Zhou, Linlin Zhang, Xiaoxia Xu, Yingying Zhao, Zesheng Li, Si Chen, Xiguo Cai, Lianzhong Zhang.

Cancer immunotherapy resistance significantly challenges its clinical application. Traditional immunotherapy strategies are limited by the difficulty in delivering macromolecular immune modulators into the hypoxic core of tumors, leading to reduced efficacy and the development of resistance. Recently, bacterial-based delivery systems have been identified as a new approach in cancer therapy since bacteria have the potential of penetrating vascular barriers, infiltrating into deep tumor tissues and delivering therapeutics. To enhance the bio-safety and therapeutic efficiency, we developed an ultrasound-controlled, gene-engineered bacterial delivery system in which the bacteria are encapsulated in platelet-liposome hybrid membranes. Upon the application of low intensity focused ultrasound (LIFU), the engineered bacteria (Escherichia coli MG1655) can secrete melittin and granulocyte-macrophage colony-stimulating factor (GM-CSF) within the tumor regions. Melittin has a direct cytotoxic activity and also promotes the presentation of tumor-specific antigens, while GM-CSF reverses the immunosuppressive microenvironment and enhances antitumor immunity. This new strategy integrates bacterial therapeutics with sonogenetics, which provides the capability of achieving precise, controllable, and non-invasive killing of tumors. Based on our research, ultrasound-activated bacterial systems may be a new strategy for cancer immunotherapy.

DOI: https://doi.org/10.1016/j.mtbio.2025.102043
Probiotics Antimicrob Proteins. 2025 Jul 23.

Viability Preservation of Probiotic Bacteria Encapsulated in Pectin-Reinforced pH-Responsive Composite Alginate Hydrogel Matrix as the Synbiotic Delivery System.

Souptik Bhattacharya, Sanjana Baidya.

  Preserving probiotics that offer mitigation of a range of digestive disorders and remedies for dysbiosis when consumed in sufficient quantities is a significant challenge in the development of medicinal products and nutritional supplements. This investigation illustrates the creation of polysaccharide-reinforced composite hydrogels that encapsulate planktonic and biofilm type probiotic cells of Alkalihalobacillus clausii and Lactobacillus plantarum. The hydrogels were prepared using ionic gelation method and response surface optimization to enhance encapsulation efficiency and cell viability against the stresses (e.g., heating, freezing, varying storage temperatures, long-term storage, and exposure to acidic and alkaline environments) typically encountered during product processing and gastrointestinal transit. The results indicate that biofilm-loaded hydrogels demonstrate superior acid resistance and better long-term viability, along with higher thermotolerance when subjected to dry heat treatment at temperatures up to 70 °C. However, their viability declines at higher temperatures (> 80 °C) even with brief exposures. Although the release of biofilm type cells in simulated intestinal fluid is lower than that of planktonic cells, the biofilm cells maintain superior viability over a longer time period. Furthermore, the extract and secretome of both the probiotic bacteria exhibit a significant antibacterial effect against pathogenic Escherichia coli (in both planktonic and biofilm form). These findings strongly suggest that pectin supplemented alginate beads can serve as a protective synbiotic transport system for these aforementioned probiotic strains.

Keywords:   Alkalihalobacillus clausii ; Lactobacillus plantarum ; Biofilm; Controlled release; Hydrogel; Probiotic encapsulation

DOI:  https://doi.org/10.1007/s12602-025-10661-9
J Microencapsul. 2025 Jul 23. 1-25

Advanced chitosan-based biopolymer systems for probiotic microencapsulation: stability enhancement and targeted release approaches.

Great Iruoghene Edo, Alice Njolke Mafe, Ali B M Ali, Emad Yousif, Raghda S Makia, Endurance Fegor Isoje, Ufuoma Augustina Igbuku, Patrick Othuke Akpoghelie, Joseph Oghenewogaga Owheruo, Rapheal Ajiri Opiti, Arthur Efeoghene Athan Essaghah, Dina S Ahmed, Huzaifa Umar.

   CONTEXT: Probiotic microencapsulation is an advanced technique designed to protect live probiotic microorganisms by enclosing them within a protective matrix, typically composed of biocompatible biopolymers.
OBJECTIVE: This review provides a comprehensive analysis of recent advancements in bio-polymer coatings for probiotic microencapsulation, with a focus on chitosan and its synergistic combinations with other materials.
METHODS: This methods highlights the necessity for continued innovation in bio-polymer coatings, emphasizing the development of bio-responsive materials, AI-driven formulation strategies, and next-generation encapsulation technologies to meet the evolving demands of functional foods and precision therapeutics.
RESULTS: Probiotic microencapsulation plays a critical role in protecting probiotics from environmental stresses, improving stability, and ensuring targeted delivery. Innovations in chitosan-based encapsulation, including its combination with bio-polymers such as alginate, gelatin, and pectin, have enhanced encapsulation efficiency, controlled release, and probiotic viability. Cutting-edge techniques such as nanotechnology, stimuli-responsive coatings, and hybrid bio-polymers are explored for their potential to optimize probiotic performance in food and pharmaceutical applications.
CONCLUSIONS: Despite these advancements, obstacles remain in ensuring consistent release profiles, mitigating the inhibitory effects of chitosan on certain probiotic strains, and optimizing large-scale production while maintaining cost-effectiveness. The need for personalized probiotic therapies has driven research into adaptive encapsulation systems tailored to individual gut microbiota compositions.

Keywords:  Chitosan-based biopolymers; controlled delivery systems; encapsulation stability; probiotic microencapsulation; targeted release mechanisms

DOI:  https://doi.org/10.1080/02652048.2025.2531776
Naunyn Schmiedebergs Arch Pharmacol. 2025 Jul 22.

Alginate/Arabic gum-chitosan-encapsulated Bacillus subtilis enhances probiotic viability and alleviates liver injury and fibrosis in cholestatic rats.

Mahla Ghanbari, Mitra Motallebi, Merat Karimi, Esmat Aghadavood, Maryam Akhavan Taheri, Sahar Ahmadi Asouri, Siavash Amiri, Hamed Mirzaei, Mohammad Esmaeil Shahaboddin.

  This study investigates the effects of encapsulated Bacillus subtilis (B. subtilis) on liver injury and fibrosis in a cholestatic rat model. Probiotics like B. subtilis have shown anti-inflammatory and antioxidant properties, but their efficacy is reduced by the harsh gastrointestinal tract (GIT) environment. Some studies have shown that encapsulation using a combination of alginate, Arabic gum, and chitosan can improve probiotic viability and promote controlled release in the intestine. In this study, male Wistar rats were randomly assigned to five groups: healthy control, cholestasis control, probiotic, free capsule, and encapsulated probiotic, to evaluate the protective effects of the encapsulated probiotic against cholestasis-induced damage. Encapsulated B. subtilis with the dosage of 3 × 109 CFU/day was administered 1 week before and 3 weeks after cholestasis induction. After treating rats with free or encapsulated B. subtilis, or with free microcapsules for 4 weeks, liver function tests, gene expression (pro- and anti-inflammatory cytokines), antioxidant status, and liver histology were analyzed. The results demonstrated that encapsulation enhanced the viability of the probiotic in the simulated gastrointestinal environment. Rats receiving encapsulated B. subtilis exhibited improved liver function, reduced pro-inflammatory cytokines (IL-6, TNF-α), and lower α-SMA gene expression (fibrosis marker), alongside increased anti-inflammatory IL-10. Additionally, antioxidant status was improved, and liver histology showed protective effects. These findings suggest that encapsulated B. subtilis can mitigate cholestasis-induced liver injury, enhance liver function, and prevent fibrosis progression.

Keywords:   Bacillus subtilis ; Cholestasis; Encapsulation; Inflammation; Liver fibrosis; Oxidative stress; Probiotic

DOI:  https://doi.org/10.1007/s00210-025-04452-w
Langmuir. 2025 Jul 22.

Amelioration of Colitis Using Colonic Microbiota-Stimulated Release of Tributyrin from Pickering Emulsion-Filled Alginate Beads.

Gege Sun, Wenbo Li, Donghui Li, Xianwen Hu, Bin Li, David Julian McClements, Shilin Liu, Kaikai Li, Yan Li.

Oral administration of tributyrin, a prodrug of butyrate, to the colon is challenging due to its unpleasant odor, rapid metabolism, and fast absorption within the upper gastrointestinal tract. In this study, the colon-targeted delivery of tributyrin was investigated using Pickering emulsion-filled alginate hydrogel beads. Initially, a tributyrin-loaded oil-in-water Pickering emulsion was formed, containing oil droplets coated with chitin nanofibers and zein colloid nanoparticles. These droplets were then encapsulated within the biopolymer network of calcium alginate beads. The potential of these structured delivery systems to control the release of tributyrin was assessed by using a simulated gastrointestinal tract, anaerobic fecal fermentation, and intestinal accumulation studies. The ability of the encapsulated tributyrin to ameliorate dextran sulfate sodium-induced colitis was evaluated. The Pickering emulsion-filled hydrogel beads retained their integrity under-simulated upper gastrointestinal tract conditions, leading to superior resistance against tributyrin hydrolysis by lipase compared to Pickering emulsions. During fecal fermentation, hydrogel beads were gradually eroded as a result of intestinal microbiota action, resulting in a sustained release of tributyrin over 48 h and a significant enhancement of butyrate levels (2.35 times at 4 h) in the cecum in a rat study. Tributyrin-loaded hydrogel beads appreciably reduced the secretion of pro-inflammatory cytokines, thereby relieving symptoms associated with colitis. In the future, it would be useful to test these tributyrin-loaded delivery systems in clinical trials to assess their potential for the treatment of colitis.

DOI: https://doi.org/10.1021/acs.langmuir.5c02248