bims-livmat 2026-04-19 papers

ACS Appl Bio Mater. 2026 Apr 13.

3D Printed In Vitro Engineered Living Material Models for Antimicrobial Development.

Emily Lazarus, Lynn M Sidor, Andrea Camacho-Betancourt, Reinaldo Dos Santos, Anne S Meyer, Iris V Rivero.

3D printing has revolutionized the field of tissue engineering and regenerative medicine, emerging as a widely adoptable strategy for the fabrication of mammalian cell-laden constructs laden with complex microenvironments. More recently, 3D printed living materials containing microorganisms have been developed. The potential for engineered 3D living materials as in vitro models for biomedical applications, such as antimicrobial susceptibility testing, is extensive; however, the need for an in-depth understanding of the relationship between the complex construct and the microorganism response still exists. Additionally, there exists a lack of multispecies engineered living material models (ELMM), which more closely mimic naturally occurring biofilms. This work includes the successful development of 3D printed single and mixed species in vitro ELMM for the development of antimicrobial therapeutics. Results successfully demonstrated the effect of maturation age on response to antimicrobial agents. Additionally, a gelatin 3D printing bath was fabricated, characterized, and yielded biomimetic 3D ELMM that could not otherwise be fabricated with low viscosity bioinks. With (1) non-traditional scaffold fabrication techniques for low viscosity bioinks, (2) enhanced understanding of the effect of biofilm maturation age on antimicrobial susceptibility, and (3) investigation into the interaction of mixed species models, 3D printed engineered living materials could provide in vitro infectious disease models for the discovery of distinct antibiofilm drugs. The results show proof-of-concept in vitro multispecies ELMM to more accurately mimic naturally occurring conditions with confirmed cell viability and maturation.

Keywords: 3D printing; alginate bioink; antimicrobial susceptibility; engineered living material; in vitro multispecies

DOI: https://doi.org/10.1021/acsabm.5c02213

Front Microbiol. 2026 ;17 1719665

Microencapsulation of Lactobacillus plantarum and Bacillus subtilis using baker's yeast cell wall: characterization and stability assessment under stress conditions.

Saima Rehman, Adnan Hussain Gora, Qurat Ul Ain, Shahina Muhammed, Brijit Xavier K, N K Sanil, Krupesha Sharma S R, Kajal Chakraborty.

Yeast cell wall components, being natural, biodegradable, and generally recognized as safe, offer a promising alternative to synthetic encapsulants for probiotic delivery. This study aimed to evaluate baker's yeast (Saccharomyces cerevisiae) cell wall as an encapsulant for improving the stability and gastrointestinal survivability of probiotics. Two probiotic strains with complementary functional traits were selected: Lactobacillus plantarum (a non-spore-forming lactic acid bacterium sensitive to gastric stress) and Bacillus subtilis (a spore-forming, robust probiotic widely used in feed and pharmaceutical applications). Probiotic cells (≈108-109 colony forming unit mL-1) were encapsulated within hollow yeast cell wall particles obtained via sequential acid-alkali treatment. Encapsulation efficiency, particle size, surface charge, structural integrity, and probiotic survival under simulated gastrointestinal conditions were evaluated. Scanning electron microscopy revealed a porous, honeycomb-like yeast cell wall structure (3-6 μm) facilitating probiotic encapsulation. FTIR analysis confirmed the successful encapsulation of Bacillus subtilis and Lactobacillus plantarum within the yeast cell wall matrix. Spectral changes indicated that encapsulation was driven primarily by non-covalent interactions, dominated by hydrogen bonding between yeast β-glucan hydroxyl groups and probiotic surface biomolecules. Dynamic light scattering showed a narrow and uniform size distribution of unloaded yeast cell wall (D50 = 0.63 μm; span = 0.42), while microencapsulation increased particle size, yielding a relatively uniform distributions for B. subtilis (D50 = 0.89 μm; span = 0.79) and a moderately polydisperse profile for L. plantarum (D50 = 1.67 μm, span = 1.28). Zeta potential values shifted from -16.4 ± 0.53 mV (unloaded yeast cell wall) to -32.73 ± 1.39 mV (B. subtilis) and -30.36 ± 0.42 mV (L. plantarum), indicating enhanced colloidal stability (p < 0.05). Encapsulation efficiencies were 89.6% ± 3.19% (B. subtilis) and 86.57% ± 1.50% (L. plantarum), significantly higher than their non-encapsulated counterparts (75.0% ± 2.26% and 40.6% ± 16.3%, respectively; p < 0.05). Encapsulated probiotics exhibited significantly improved survival in simulated gastric and intestinal fluids compared with free cells (p < 0.05). Baker's yeast cell wall-based encapsulation significantly enhances probiotic stability, colloidal behavior, and gastrointestinal tolerance through strain-specific physicochemical interactions. This approach offers a safe and effective delivery platform for functional feed and pharmaceutical applications.

Keywords: acid exposure; enzyme exposure; in vitro; microencapsulation; probiotics

DOI: https://doi.org/10.3389/fmicb.2026.1719665

Chempluschem. 2026 Apr;91(4): e202500586

Cell-in-Shell Metacells in Single-Cell Nanoencapsulation.

Duc Tai Nguyen, Nayoung Kim, Sang Yeong Han, Hyunwoo Choi, Insung S Choi.

Single-cell nanoencapsulation (SCNE) enables the direct integration of synthetic materials with living cells, forming cell-in-shell structures that augment native cellular functions without genetic modification. While SCNE has advanced applications in cytoprotection and cell-surface engineering, its full potential remains constrained by the absence of a unifying conceptual framework. In this Concept report, we introduce the term "metacells" to define a new class of engineered, living cell-in-shell systems endowed with dynamic functionality, environmental responsiveness, and programmable behavior. We propose that metacells are characterized by three core functional hallmarks-reconfigurability, loadability, and motility-which collectively distinguish them from conventional SCNE platforms. Through selected examples, we illustrate how these features enable metacells to sense and respond to external stimuli, carry and release functional payloads, and exhibit guided or autonomous motion. By establishing a foundational definition and organizing framework for metacells, this report provides a roadmap for future research at the intersection of materials science, synthetic biology, and cellular engineering, with implications for advanced therapeutics, microscale robotics, and interactive biohybrid systems.

Keywords: artificial spores; cell‐in‐shell structures; metacells; nanobiohybrids; single‐cell nanoencapsulation

DOI: https://doi.org/10.1002/cplu.202500586

Microb Cell Fact. 2026 Apr 13.

From lab to law: emerging applications, potential benefits, evolving regulatory framework and challenges for engineered probiotics.

Francesco Di Pierro, Aswin Thacharodi, Muthiah Kumaraswami, Alexander Suvorov, Jure Zupet, Nicola Zerbinati.

Keywords: Engineered bacteria; Genetically modified microorganisms; Legal and regulatory framework; Prokaryotic and human DNA; Safety

DOI: https://doi.org/10.1186/s12934-026-02997-w