bims-livmat 2026-07-19 papers

bims-livmat

Biomed News

on Living materials

Issue of 2026–07–19
eight papers selected by
Sara Trujillo Muñoz, Leibniz-Institut für Neue Materialien

Self-Growing and Mechanically Tunable Living Materials with Paenibacillus mucilaginosus Extracellular Polymeric Substances.
PEG-Based Living Hydrogels Engineered for Tunable Production of Bioactive Lipopeptides.
A signal peptide-guided approach towards in situ functionalization of bacterial nanocellulose in Komagataeibacter rhaeticus.
Bioinspired microcapsule reactor with engineered probiotics for IBD therapy.
Engineered Escherichia coli Nissle 1917 secreting anti-TNF-α nanobody as a single-strain live biotherapeutic for inflammatory bowel disease.
Microalgae-based living biomaterials for immunoengineering: from biological functions to therapeutic systems.
Microencapsulation of engineered bacteria towards whole-cell-based environmental biosensing.
Enhancing viability and stability of lactic acid bacteria co-encapsulated with natural pigments using whey protein isolate and gum arabic complex coacervates.

ACS Appl Polym Mater. 2026 Jul 10. 8(13): 10300-10311

Self-Growing and Mechanically Tunable Living Materials with Paenibacillus mucilaginosus Extracellular Polymeric Substances.

Yifan Cui, Stéphane Bernhard, Mathias Steinacher, Nika Petelinsek, Lorenzo Minervini, Stefan Mommer, Mark W Tibbitt.

  Engineered living materials (ELMs) typically embed functional cells in nonliving matrices, limiting growth, remodeling, and long-term adaptation at the material level. Here, we introduce extracellular polymeric substances (EPS) produced by Paenibacillus mucilaginosus as a living carrier matrix for ELMs. P. mucilaginosus EPS possesses suitable rheological behavior, such as shear thinning and elastic recovery, required for extrusion-based fabrication. Its mechanical properties can be further tuned through dynamic covalent cross-linking via boronate ester formation or physical reinforcement with Laponite or xanthan gum. With boronate ester cross-linking (18 mM), the storage modulus increased from 100 to 800 Pa. The inclusion of 0.5 w/v % Laponite further increased the modulus to 1300 Pa. Uniquely, a living matrix comprised ofP. mucilaginosus EPS provides a substrate for material growth. As a proof of concept, we manufactured photosynthetic living materials by embedding a photosynthetic cyanobacterium strain,Synechococcus sp. PCC 7002, in the EPS matrix and printed into defined architectures. Both P. mucilaginosus and cyanobacterium PCC 7002 remained viable and grew over 30 days. Matrix outgrowth and microbial colonization enabled the expansion of the living constructs within the printed structure. This work establishes P. mucilaginosus EPS as a candidate living scaffold for self-growing and mechanically tunable ELMs.

Keywords:  carbon capture; dynamic covalent chemistry; extracellular polymeric substances; living materials; self-growing

DOI:  https://doi.org/10.1021/acsapm.6c01028
ACS Appl Polym Mater. 2026 Jul 10. 8(13): 10210-10222

PEG-Based Living Hydrogels Engineered for Tunable Production of Bioactive Lipopeptides.

Jeffrey A Reed, Moises M Gutierrez, Douglas A Dougherty, Asad Bin Zaman, Ryan R Hansen.

  Encapsulation of microbial cells within nanoporous hydrogels creates dynamic and responsive living materials well-suited for biotherapeutic applications. Bacillus subtilis is a promising microbe in this application as it is generally regarded as safe, can be sporulated for long-term stability and resistance to nonideal environments, and can produce antimicrobial and anticancer molecules such as the cyclic lipopeptide surfactin. Here, we examine the growth of B. subtilis cells and corresponding production of surfactin after encapsulation within poly-(ethylene glycol) (PEG) hydrogels at varied levels of nanoconfinement. Encapsulation was achieved through Michael-type addition reactions between PEG diacrylate and PEG tetrathiol macromers, where macromer molecular weight was systematically varied to generate hydrogels across a range of average mesh sizes (9-19 nm). Hydrogels had varied Young's modulus (7.3 ± 1.7 kPa to 16.4 ± 0.7 kPa) and provided a 7-fold range in small molecule diffusivity. In-situ cellular growth monitoring and surfactin quantification revealed that all hydrogels stimulated the production of surfactin with verified antibacterial activity and in a manner tunable with mesh size. Smallest mesh sizes drove highest surfactin production, a ∼5-fold increase relative to equivalent cultures of unconfined cells. Cell loading was then varied in 9 nm mesh size hydrogels to reveal that low cell loading (0.1-1 × 104 cells per μL hydrogel) promoted sustained growth and surfactin production proportional to the number of cells loaded. Conversely, hydrogels loaded with excessive cells (2.5-7.5 × 104 cells per μL hydrogel) resulted in unsustained growth and diminished surfactin production. Finally, to develop a more robust material, B. subtilis endospores were encapsulated into hydrogels at optimized conditions. Spore-laden hydrogels retained the capability to produce surfactin after exposure to dehydration and temperature stress. These results indicate that hydrogel encapsulation stimulates B. subtilis surfactin production according to the level of nanoconfinement to achieve a tunable engineered living material for production of bioactive molecules.

Keywords:  bacteria; biotherapeutics; engineered living materials; hydrogels; poly(ethylene glycol); surfactin; wound dressings

DOI:  https://doi.org/10.1021/acsapm.6c00761
J Biol Eng. 2026 Jul 17.

A signal peptide-guided approach towards in situ functionalization of bacterial nanocellulose in Komagataeibacter rhaeticus.

Jenni Vannas, Amritpal Singh, Bibi Hannikainen, Michelle Alexandrino de Assis, Rodrigo Ledesma-Amaro, Tom Ellis, Rahul Mangayil.

   BACKGROUND: Bacterial nanocellulose (BC), produced by Komagataeibacter species, is an ideal scaffold for biological Engineered Living Materials (bioELMs) research. Current BC functionalization strategies often rely on secondary microbial hosts or post-production enzyme immobilization, limiting the scalability and modularity required for programmable bioELMs. Establishing a single-chassis system capable of simultaneous biopolymer synthesis and in situ functionalization remains a primary objective in bioELM research. This study addresses the need by benchmarking signal peptide-mediated protein translocation in K. rhaeticus iGEM, a model bacterium for BC-based bioELMs, enabling a synthetic biology framework for single-chassis based biomaterial functionalization.
RESULTS: Genome-wide analysis confirmed the presence of a complete Sec translocation machinery in K. rhaeticus. Through liquid chromatography-tandem mass spectrometry and SignalP 5.0 prediction, native signal peptides were identified and evaluated alongside previously characterized heterologous signal peptides using β-lactamase and mScarlet as cargo proteins. Protein translocation was found to depend on signal peptide identity, cargo type, and expression mode. Fluorescence imaging revealed cytoplasmic, polar, and peripheral localization patterns, confirming functional engagement with the native translocation machinery. A key limitation identified was the retention of recombinant proteins within the periplasm, restricting extracellular availability. Despite this, signal peptide-mediated translocation enabled the incorporation of enzymatic activity into BC during biosynthesis. A post-growth osmotic shock-release strategy increased measurable enzymatic activity by 30%, demonstrating a practical route to overcome this physiological bottleneck while maintaining the biomaterial production capacity.
CONCLUSIONS: This study benchmarks signal peptide-dependent protein translocation in K. rhaeticus and identifies periplasmic retention as a key constraint for extracellular protein release. By linking protein translocation to in situ BC functionalization, this work establishes a synthetic biology framework that supports the development of K. rhaeticus as a single-chassis platform towards the production of functionalized bioELMs.

Keywords:   Komagataeibacter rhaeticus ; Bacterial nanocellulose; Microbial chassis engineering; Protein localization; Signal peptides; Synthetic biology

DOI:  https://doi.org/10.1186/s13036-026-00734-w
Nat Commun. 2026 07 13. pii: 6095. [Epub ahead of print]17(1):

Bioinspired microcapsule reactor with engineered probiotics for IBD therapy.

Minhui Xu, Yuanchun Du, Guangfu Feng.

Although probiotic-based bionic strategies show therapeutic promise for inflammatory bowel disease, their clinical translation is limited by poor gastric acid survival, inefficient intestinal colonization and inadequate targeting. Inspired by the multi-level cooperative mechanism of defense protection-danger sensing-tissue repair observed in coral communities, we developed a core-shell bionic microcapsule reactor (MY-E@SS). Here we show that the multifunctional bionic shell enables safe delivery of engineered bacteria through the gastrointestinal tract. Upon reaching inflamed intestinal sites, these bacteria sense the pathological microenvironment and responsively release an anti-inflammatory peptide. In a male murine model of inflammatory bowel disease, this system exhibited excellent biocompatibility and pronounced therapeutic efficacy, restoring intestinal barrier integrity, attenuating systemic inflammation and oxidative stress, modulating respiratory metabolism, and reestablishing microbial homeostasis. Mechanistically, therapeutic effects were attributed to inhibition of TNF-α/NF-κB signaling pathway. This work provides an intelligent platform to modulate inflammatory microenvironments and advance therapies for complex diseases.

DOI: https://doi.org/10.1038/s41467-026-72027-1
Front Immunol. 2026 ;17 1865862

Engineered Escherichia coli Nissle 1917 secreting anti-TNF-α nanobody as a single-strain live biotherapeutic for inflammatory bowel disease.

Qiumei Zhu, Shitao Feng, Zhende Yan, Zijian Wang, Xinran Huang, Changning Sun, Bingqiang Zhang, Xinrui Li, Yuchao Gu.

   Background: The rising global incidence of inflammatory bowel disease (IBD) creates an urgent need for safer, gut-targeted therapies. Current treatments, from small-molecule drugs to systemic anti-tumor necrosis factor-alpha (TNF-α) biologics, are frequently limited by off-target immunosuppression, heightened infection risk, and poor mucosal bioavailability. Engineered probiotic-based live biotherapeutics offer a compelling alternative by enabling localized drug production within the inflamed intestine.
Methods: We engineered Escherichia coli Nissle 1917 (EcN) to secrete the anti-TNF-α nanobody MT1, creating the streamlined, single-strain platform EcN-MT1. Five signal peptides were screened, and plasmid-based and CRISPR-Cas9-mediated chromosomal integration strategies were compared. Structural modeling and molecular dynamics simulated MT1-murine TNF-α (mTNF-α) binding. Binding affinity and anti-inflammatory activity were assessed by ELISA and in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Therapeutic efficacy was further evaluated in a dextran sulfate sodium (DSS)-induced murine colitis model by assessing body weight, disease activity index (DAI), colon length, histopathology, colonic pro-inflammatory cytokines, and 16S rRNA gut microbiota profiling.
Results: Among the tested signal peptides, α-hemolysin (HlyA) achieved highest secretion (4.6 mg/L), and the plasmid-based strain markedly outperformed genomic integrants without impairing growth. Simulations confirmed stable complementarity-determining regions (CDR)-mediated binding, consistent with the high affinity (EC50 27.9 nM) and potent suppression of LPS-induced mRNA expression of Tnf and interleukin-1β (Il1b) in macrophages. In the DSS-induced murine colitis model, oral administration of EcN-MT1 significantly attenuated weight loss, improved DAI scores, and preserved colon length. Histopathological analysis revealed reduced mucosal ulceration, crypt loss, and immune cell infiltration, accompanied by downregulated colonic Tnf and Il1b mRNA. Notably, EcN-MT1 treatment restored gut microbial diversity, corrected dysbiosis, and enriched beneficial taxa linked to butyrate production, barrier enhancement, and anti-inflammatory effects.
Conclusion: This study establishes EcN-MT1 as a potent, orally deliverable live biotherapeutic that achieves localized TNF-α neutralization while concurrently promoting microbial and mucosal homeostasis, offering a novel and translatable strategy for IBD treatment.

Keywords:  Escherichia coli Nissle 1917; gut microbiota; inflammatory bowel disease; live biotherapeutic; nanobody

DOI:  https://doi.org/10.3389/fimmu.2026.1865862
Biomater Sci. 2026 Jul 17.

Microalgae-based living biomaterials for immunoengineering: from biological functions to therapeutic systems.

Haishuang Zhu, Ruoxi Wang, Min Zhou.

The immune system plays a central role in maintaining physiological homeostasis and protecting against infections, cancer, and inflammatory diseases. Immunoengineering, broadly defined as the strategic design and manipulation of immune responses, has emerged as an interdisciplinary field integrating immunology, materials science, and biomedical engineering, enabling substantial advances in the precise modulation of immune function. However, conventional immunomodulatory materials-such as synthetic polymers, nanoparticles, and biologically derived matrices-generally function as passive platforms, with limited capacity to dynamically adapt to complex and evolving pathological microenvironments. To address these limitations, living biomaterials have emerged as a transformative paradigm. Among them, microalgae represent a particularly promising and versatile platform, owing to their intrinsic photosynthetic oxygen-generating capability, diverse production of bioactive metabolites, favorable biocompatibility, scalability, and amenability to genetic engineering. Microalgae can alleviate hypoxia, modulate inflammatory signaling pathways, and produce antioxidant and anti-inflammatory metabolites as well as extracellular vesicles, thereby enabling cross-kingdom communication with host systems. Recent advances have further demonstrated their integration with polymers, nanomaterials, and microbial systems to construct multifunctional biohybrid platforms for active and adaptive immune modulation. Despite rapid progress, the field remains fragmented, and a systematic framework for translating microalgae-based living biomaterials into immunomodulatory therapies is still lacking. This review provides a comprehensive overview of microalgae-derived living biomaterials for immunoengineering, including their fundamental biological characteristics and mechanisms of immune regulation, key engineering strategies (such as encapsulation, biohybridization, and genetic engineering), and emerging therapeutic applications. In addition, current challenges and future perspectives for clinical translation are critically discussed.

DOI: https://doi.org/10.1039/d6bm00677a
Front Bioeng Biotechnol. 2026 ;14 1851287

Microencapsulation of engineered bacteria towards whole-cell-based environmental biosensing.

Luana Cuvillier, Guillaume Nonglaton.

   Introduction: Legitimate concerns about the quality of environmental waters are on the rise. As a consequence, efforts are being made by both the scientific community and policymakers to develop proficient methods for the monitoring and detection of pollutants of emerging concerns (PECs). In line with the European Union's "Zero Pollution" action plan, there is a growing need to develop real-time, multiplexed, on-site monitoring systems. The study explores the encapsulation of engineered Pseudomonas putida cells designed to produce a luminescent response upon exposure to specific analytes. The aim was to develop a suitable, miniaturized, biocompatible, safe-and-sustainable-by-design, sensing element for future integration with optical-electrochemical transduction systems.
Methods: Genetically modified P. putida cells were encapsulated in sub-200 µm alginate microcapsules using a layer-by-layer method with poly-L-lysine (PLL) to avoid bacterial escape. Capsules morphology and structure were characterized using Laser Scanning Confocal and cryo-Scanning Electron microscopies. Effects of cell load, storage temperature, and storage medium were evaluated through encapsulated cells' fluorescent response to induction. Long-term fluorescent activity was evaluated over a 2-month period. Response-time of the encapsulated cells was investigated using both experimental and diffusion modelling approaches.
Results: Encapsulation strategy using alginate-PLL capsules revealed a good mechanical stability and resistance to saline water, with minimal cell leakage. About 75% of encapsulated cells remained viable after 45 days, and fluorescence increase upon induction was still observed after 2 months of storage at room temperature without nutrient supply. These findings suggest that a subpopulation of cells entered a dormant or low-metabolic state, enabling long-term sensing under non-ideal conditions. Higher cell loads correlated with stronger responses, likely due to an increased fraction of metabolically reactivable cells. Encapsulated cells were also reusable, showing measurable sensing response for five sensing cycles within 2 weeks.
Discussion: Results demonstrate that response dynamics are primarily governed by reduced metabolic activity and limited oxygen access, rather than by analytes diffusion through the hydrogel matrix.

Keywords:  alginate-poly-L-lysine microcapsules; cell confinement; diffusion modelling; layer-by-layer encapsulation; long-term viability; whole-cell biosensor

DOI:  https://doi.org/10.3389/fbioe.2026.1851287
Int J Biol Macromol. 2026 Jul 17. pii: S0141-8130(26)03547-6. [Epub ahead of print] 153602

Enhancing viability and stability of lactic acid bacteria co-encapsulated with natural pigments using whey protein isolate and gum arabic complex coacervates.

Zhi-Hong Zhang, Jiaying Wang, Jialin Chen, Xueyun Zheng, Quancai Sun, Ye Peng, Xiao Ying, Xiaolan Li, Xianli Gao.

  This study aimed to establish a natural pigment-based synbiotic microcapsule system for lactic acid bacteria (LAB) protection, and to reveal the triple synergistic protection mechanism (pigment prebiotic effect + WPI/GA physical barrier + pigment antioxidant activity). This study first evaluated the novel prebiotic effects of three natural pigments (chlorophyll, betalain, and sodium copper chlorophyllin) on Lactobacillus plantarum, Lactobacillus bulgaricus, and Streptococcus thermophilus. Based on these findings, a synbiotic microcapsule system was subsequently developed by co-encapsulating the three pigments with the probiotics via whey protein isolate (WPI)/gum Arabic (GA) complex coacervation. The results indicate that the three natural pigments possess the potential to function as prebiotics, significantly enhancing the growth and metabolic activity of LAB strains. The encapsulated L. plantarum exhibited superior stress resistance, and the encapsulation efficiency of microcapsules containing natural pigments was 20% higher than that of the control group. Fourier transform infrared (FT-IR) spectroscopy confirmed strong hydrogen bonding and electrostatic interactions between natural pigments and WPI/GA wall materials, thereby enhancing the compactness of the microcapsule matrix and improving its protective performance. The findings provide a feasible and scalable strategy and theoretical references for the development of stable synbiotic functional foods.

Keywords:  Complex coacervation; Lactic acid bacteria; Microencapsulation; Natural pigment; Prebiotic effect; Stress resistance

DOI:  https://doi.org/10.1016/j.ijbiomac.2026.153602