Biomacromolecules最新文献

To combat drug-resistant bacteria, antimicrobial agents with tunable and multi-modal mechanisms are urgently needed. While membrane-disrupting polymers have been widely explored, precisely regulating their membrane interactions and downstream metabolic effects remains challenging. Here, using naturally occurring lipoic acid, we designed cationic cyclic oligo(disulfide)s (CCOs) that induce targeted membrane depolarization and trigger distinct downstream metabolic responses. CCOs exhibit species-specific killing mechanisms: membrane depolarization in Staphylococcus aureus and reactive oxygen species induction in Escherichia coli. The cationic-to-hydrophilic ratio governs both membrane interactions and metabolic regulation. Coarse-grained molecular dynamics simulations revealed that fully cationic CCO1 adsorbs via electrostatic forces, whereas CCO2-64%, bearing partial hydrophilic groups, relies on a balance of electrostatic and van der Waals interactions, underlying its enhanced antibacterial selectivity. Transcriptomic analysis further showed that CCO1 disrupts ribosome assembly and sulfur-containing amino acid metabolism, while CCO2-64% downregulates oxidoreductase activity and nitrogen metabolism. With favorable biosafety and potent efficacy against methicillin-resistant S. aureus in a murine cutaneous abscess model, CCOs represent a tunable antimicrobial system with considerable clinical translation potential.

Peptoids (N-substituted glycines) are a promising material platform for next-generation biomedical applications, as control over monomer sequence enables the design of functional materials with defined morphologies, which in turn allow for precise interactions with biological targets. Traditional synthetic approaches for peptoids suffer from a tradeoff between scalability and synthetic versatility. Solid-phase submonomer synthesis methods facilitate sequence specificity and side chain diversity but require large reagent excesses and remain challenging to monitor. Meanwhile, solution-phase methods have limited sequence definition and intensive purification requirements. Here, we present a Rink amide soluble support to synthesize peptoids via the submonomer method using reduced reagent excesses and a simple workup procedure while supporting iterative synthesis of diverse linear and cyclic peptoid architectures. This solution-phase approach allows for real-time reaction monitoring via ReactIR and mass spectrometry. The Rink amide soluble support is a flexible platform that bridges the gap between solid- and solution-phase methods and can simplify synthesis in future peptoid studies.

Humidity sensing membranes combining high sensitivity, mechanical robustness, and long-term stability remain challenging to fabricate via simple, scalable routes. Using a surfactant-free ionic liquid microemulsion and nanofibrillar bacterial cellulose, we fabricated a short-range ordered bicontinuous porous composite membrane in one step. In situ polymerized poly(ionic liquid) forms strong hydrogen-bonded interfaces with cellulose, while microemulsion templating generates interconnected pores. Carbon black (CB) and isopropyl alcohol (i-PA) synergistically regulate the membrane structure and properties. Increasing the CB content enhances mechanical strength and lowers electrical resistance through conductive percolation, whereas i-PA controls fracture morphology and porosity. The optimized formulation (5 wt % CB, 37.5% excess i-PA) achieves a tensile strength of 2.66 MPa and a relative resistance response of 87% at 95% relative humidity, with negligible performance degradation after 1000 tensile cycles. These findings establish ionic liquid microemulsion templating as a scalable route to durable, porous iontronic membranes for high-performance humidity monitoring.

Polypeptoids, or poly(N-substituted glycines), are highly programmable bioinspired polymers whose N-substituted backbone eliminates backbone chirality and hydrogen-bond donor functionality. Consequently, side-chain chemistry, backbone structure, and macromolecular topology are the primary determinants of conformation, self-assembly, and bioactivity. Recent synthetic advances have expanded the structural diversity of polypeptoids, enabling systematic investigation of structure−property relationships. Understanding these relationships provides a foundation for programming function across multiple length scales, from single-chain conformations to supramolecular assemblies and bulk materials. In this Perspective, we discuss recent advances in polypeptoid-based polymer synthesis and architecture, with particular emphasis on the structure−property relationships that govern their behavior as functional polymers and guide the development of functional materials for antibacterial applications, cancer therapy, tissue engineering, biological coatings, ion-conducting systems, catalytic materials, and sensing platforms. Establishing robust structure−property relationships will be essential for advancing polypeptoids from versatile polymer platforms to next-generation functional biomaterials.

With the rapid advancement of flexible electronics and smart agriculture, plant wearable sensors have attracted increasing attention for precision agricultural monitoring. However, conventional rigid sensors suffer from mechanical incompatibility with soft plant tissues and invasive attachment, limiting long-term in situ monitoring. Here, a flexible triboelectric nanogenerator (TENG) sensor based on a conductive ionic hydrogel (PAM-Li-Zn TENG) was developed and integrated with a Bluetooth module for wireless plant monitoring. The hydrogel composed of PVA, AM, LiCl, and zinc chloride provided excellent flexibility, ionic conductivity, and water retention. The optimized hydrogel containing 3 wt % glycerol exhibited a tensile strength of approximately 124 kPa and an elongation at break of nearly 582%. With PDMS encapsulation, the sensor achieved structural stability and reliable operation. Combined with machine learning algorithms, the PAM-Li-Zn TENG enabled intelligent identification of plant growth states and abiotic stress monitoring, generating an open-circuit voltage of 312 V and a short-circuit current of 31 μA under 50 N force at 1.6 Hz.

Efficient gene delivery to mitochondria remains a major challenge in the development of organelle-targeted therapeutics. Here, we report the rational design and evaluation of helix stabilized mitochondria-targeting peptides (MTPs) via the incorporation of 2-aminoisobutyric acid (Aib), a noncanonical residue known to promote helical structure and increase membrane permeability. Three essential peptides were newly synthesized by systematically substituting alanine or glycine residues with Aib in a peptide derived from the mitochondrial outer membrane protein mitoNEET. Structural analyses using molecular dynamics (MD) simulations and circular dichroism (CD) spectroscopy confirmed increased helical content in the Aib-substituted peptides. Compared with the unmodified peptide, the Aib-substituted peptides exhibited significantly increased HeLa cell uptake and mitochondrial localization. Furthermore, conjugation of the designed MTPs with a cationic arginyl−histidine repeat peptide enabled efficient delivery of plasmid DNA into mitochondria, leading to successful expression of mitochondrial-localized reporter genes. These findings demonstrate that Aib-induced helix stabilization is a powerful strategy for increasing mitochondrial gene delivery and provide a versatile platform for peptide-based mitochondrial therapeutics.

Green adhesives are gradually replacing traditional synthetic adhesives due to their eco-friendly properties and sustainability. However, the industrial applications of green adhesives are limited by their lower strength and higher cost. Here, inspired by sandcastle worms, we show green adhesives with combined high adhesive strength and low cost by enhancing the interaction of γ-PGA/ε-PLL coacervates through the introduction of tannic acid. The preparation method is green, simple, and fast. Specifically, taking advantage of non-covalent interactions between three components, the synergistical enhancement of cohesion and adhesion leads to the excellent adhesive strength, exhibiting a maximum adhesive strength of 18.21 MPa and an instant adhesive strength of 1.54 MPa. Notably, the non-covalent interactions endow the adhesive with reversible debonding-on-demand and recyclability, retaining its original adhesive strength even after 10 cycles. The feasibility to simultaneously overcome the major bottlenecks for green adhesives provides new insights for developing other sustainable green materials.

Stereochemical modification represents a powerful strategy for optimizing the therapeutic potential of antimicrobial peptides. Herein, we present a comprehensive structural and biophysical characterization of ecPis-2s and its epimerized analog, d-ecPis-2s, featuring a single d-F substitution. Although both peptides possess identical net charges and global hydrophobicity, our results reveal that the d-substitution acts as a conformational switch altering membrane interaction dynamics and antimicrobial efficacy. CD and solution NMR spectroscopy demonstrate that d-ecPis-2s maintains a similar overall helical character but adopts a distinctive N-terminal structural bend. Structural refinements and topology studies based on solid-state NMR elucidated that d-configuration at position 2 promotes a deeper sequestration of the N-terminal aromatic triad (F1−F3) into the hydrophobic membrane core. This aromatic anchor drives the peptide backbone and consecutively the aromatic side chains into the lipid bilayer, enhancing membrane tension, pore-forming kinetics and lipid packing disruption, which correlates directly with increased antimicrobial activity.

Silk nanofibers (SNFs) are promising bio-based reinforcements for flexible sensors, but their integration into conductive elastomers is limited by complex processing and inefficient nanofibrillation. Here, a green one-pot strategy was developed to integrate silk carboxylation, nanofibrillation, and in situ photopolymerization within a hydrated oxalic acid/choline chloride deep eutectic solvent system. The resulting carboxyl-rich SNFs had an average length of 271.51 nm and a carboxyl content of 1.249 mmol g⁻¹. Glycidyl methacrylate enabled formation of a physically and chemically dual-crosslinked SNF/poly(deep eutectic solvent) (SNF/PDES) elastomer, exhibiting 1080% strain, 1.28 MPa tensile strength, and 9.57 MJ m⁻³ toughness. As a strain sensor, the elastomer showed gauge factors of 0.861, 1.143, and 2.018 across 0−500% strain and stable output over 1000 cycles. This sustainable strategy provides a scalable route toward high-performance wearable sensing materials.

This study addresses knowledge gaps concerning interactions between barley mixed-linkage glucans (MLGs) and TEMPO-oxidized cellulose nanocrystals (TCNC), focusing on underlying physiochemical and thermodynamic principles. Combining dynamic light scattering (DLS), quartz crystal microbalance with dissipation monitoring (QCM-D), and isothermal titration calorimetry (ITC), we systematically investigated MLG solution properties, adsorption at cellulose surfaces, and thermodynamics of interaction. DLS revealed limited aqueous solubility of MLGs, with elevated temperatures promoting aggregate formation and reducing solution stability. QCM-D experiments showed that MLG forms thick hydrogel layers at cellulose interfaces and Voigt modeling confirmed temperature-dependent viscoelastic properties of the layers. Analysis of QCM-D data with van’t Hoff approach together with ITC showcased only minor enthalpic contributions and predominantly entropic interactions. Altogether, these findings clarify MLG-cellulose interconnections and interlink between solubility, interfacial behavior, and functionalities of MLG in all-polysaccharide materials architectures. Additionally, the results point towards MLG providing a hydrating layer in plant cell walls in nature.