Biomacromolecules最新文献

Solid-state polymorphic transition from cellulose I to II (mercerization) generally requires high alkali concentrations (>12−15 wt %) to overcome hydrogen-bonding networks and topological barriers. In this study, we elucidated the phase behavior of cellulose in a high-temperature, low-concentration regime using in situ Fourier-transform infrared spectroscopy in D₂O and non-negative matrix factorization (NMF). Phase mapping demonstrated that the alkali threshold for mercerization decreased to approximately 5 wt % above 60 °C. NMF analysis established kinetic markers that distinguished alkali-induced structural evolution from overlapping spectral responses. The results suggest that elevated temperature promotes transient local loosening of cohesive contacts, accompanied by reorganization of structured water and increased conformational freedom. Spectroscopic tracking of backbone geometry revealed a Twist−Stabilize−Lock mechanism initiated by reduction of the glycosidic bond angle. This thermally assisted unlocking process facilitates alkali-assisted structural rearrangement under dilute conditions, extending mercerization into a low-alkali regime distinct from dissolution−regeneration pathways. These findings provide a mechanistic basis for reducing alkali consumption and designing thermally assisted cellulose processing and surface-modification strategies.

Liver fibrosis is a major complication of chronic liver injury, driven in part by Signal Transducer and Activator of Transcription 1 (Stat1). This study evaluated passively liver-targeted polymeric nanocarriers delivering Stat1 siRNA (siSTAT1) to treat steatohepatitis and fibrosis in a thioacetamide (TAA) mouse model. Two polyplex nanocarriers with different core−corona ratios, EN15 and EN76, were tested in TAA-treated mice and activated human and murine hepatocytes. In vitro, both formulations enabled efficient cellular uptake and Stat1 silencing, reducing TAA-induced lipid accumulation. Through an In vivo approach, mice received TAA for 16 weeks followed by four weeks of siSTAT1 treatment. Both formulations reduced collagen deposition, hepatic inflammation, and fibrosis scores. Notably, EN76, which preferentially targets non-parenchymal cells, showed superior antifibrotic efficacy compared with EN15. These findings highlight Stat1 as a key driver of steatohepatitis and fibrosis and support passive siRNA delivery, particularly via EN76, as a promising therapeutic strategy.

Controlling dye emission under confinement remains challenging because of aggregation-caused quenching. Here, we report a confinement-activated mechanism for polymer-mediated regulation of interfacial and dye emission in cellulose nanocrystal (CNC)-based systems. PEG induces negligible photophysical changes in suspension but dramatically enhances fluorescence in films, increasing the quantum yield of rhodamine 6G (Rh6G) from 0.03% to 57.42% with a prolonged fluorescence lifetime. Spectroscopic and molecular dynamics analyses show that PEG regulates dye−dye and CNC-dye organization through steric and interfacial effects. Solvent-mediated interactions largely screen these perturbations in suspension, whereas solvent removal enables cooperative regulation by the rigid CNC framework and flexible PEG chains, redistributing local dimer geometries and excitonic coupling. The fluorescence enhancement extends to multiple cationic dyes but depends strongly on the molecular structure. These findings establish a molecular framework linking polymer-mediated interfacial regulation, confinement, and dye structure, providing a strategy for tuning the emission in polysaccharide-based materials.

Functionalized peptide−polymer conjugates have been used for applications such as drug delivery, catalysis, metal-ion binding, and gas separation due to their low toxicity. Reported herein is an acyclic aromatic dipeptide−polynorbornene conjugate decorated with carboxylate groups for cation binding. The peptide−polymer conjugate is prepared using an aromatic dipeptide scaffold functionalized with norbornene that readily self-assembles to form spherical aggregates. The self-assembly is covalently captured using ring-opening metathesis polymerization in the presence of a crosslinker to give robust nanospheres. Hydrolysis of the peptide C-terminus affords the carboxylated spheres with excellent thermal stability. These nanospheres can selectively remove 27.94 mg g⁻¹ of Hg(II) ions, which translates to an 86.5% removal efficiency. The nanospheres being insoluble can be readily isolated, regenerated, and reused for mercury removal without compromising the removal efficiency. Owing to their stability, selectivity, and reusability, the carboxylated spheres offer exciting prospects for environmental remediation applications.

Arabinoxylans are ubiquitous plant biopolymers present in large amounts in cereal bran, a major underutilized side stream of the agrifood industry. Their unique structural properties make them promising matrices for the design of hydrogels for nutritional and pharmacological applications. We report the controlled production of laccase-crosslinked arabinoxylan hydrogels derived from wheat (WAX) and rye (RAX) bran with tuned porous properties via the modulation of freeze-drying temperature, with implications for biostimulatory encapsulation and release. Freezing in liquid nitrogen generated smaller pore sizes in both systems, while RAX hydrogels consistently displayed higher porosity and elastic moduli than WAX hydrogels, reflecting differences in chemical cross-linking density, solid content, and physical network organization. Rheological analyses revealed a correlation between solid content and porosity with enhanced elastic properties, highlighting the poroelastic contributions to hydrogel mechanics. The hydrogels exhibited varying encapsulation and retention ability of the target biomolecules (glucose, tryptophan, and green fluorescent protein), reflecting differences in molecular size and chemistry. Retention of small molecules was dictated primarily by matrix affinity, whereas larger proteins were retained predominantly based on pore size and porosity. Enzymatic degradation by a gut bacteria β-xylanase-triggered cargo release, demonstrating the potential of arabinoxylan hydrogels, as targeted gastrointestinal delivery platforms.

Three-dimensional bioprinting offers transformative potential for functional disease modeling and tissue engineering. These applications demand effective biomaterial sterilization to ensure reproducibility and clinical translation. This study evaluated pharmacopeia-standard disinfection and sterilization methods, including autoclaving, dry heat treatment (aerobic and anaerobic), ethanol washing (70%), UV irradiation, and filtration on three thermoresponsive hydrogels. The investigated hydrogels consist of Pluronic F127 (poloxamer 407) or two poly(2-oxazolines)/poly(2-oxazine) based block copolymers, namely poly(2-methyl-2-oxazoline)-b-poly(2-n-propyl-2-oxazine) (pMeOx-b-pnPrOzi), or poly(2-methyl-2-oxazoline)-b-poly(2-phenyl-2-oxazine)-b-poly(2-methyl-2-oxazoline) (pMeOx-b-pPheOzi-b-pMeOx). Results showed that ethanol washing and UV irradiation sterilized inefficiently, while dry heat treatment caused partial thermal degradation (all polymers), compromised 3D-printability, and increased cytotoxicity (Pluronic F127), likely due to the formation of oxidative degradation products. Filtration effectively sterilized both pMeOx-based block copolymers, while Pluronic F127 required a combined approach of autoclaving and triple filtration to achieve complete sterility. Overall, filtration and autoclaving emerged as the most suitable sterilization method, balancing chemical stability, mechanical integrity, printability, and cytocompatibility.

Hemoglobin (Hb) can act as a dynamic supramolecular building block through the reversible dissociation of the α₂β₂ tetramer into αβ dimers. For this study, we designed structurally defined bicyclic monomers in which the β subunits in two Hb molecules are bridged through four-armed PEG of different molecular weights (10 and 40 kDa). These bicyclic monomers undergo concentration-dependent supramolecular ring-opening polymerization, enabling predictable control of polymer structure from discrete monomers to polymer particles and finally to a percolated polymer gel network. Extensive physicochemical analyses revealed quantitative shifts in polymerization equilibria that govern these supramolecular assemblies. Furthermore, intramolecular ββ-cross-linking of Hb moiety with bis-(3,5-dibromosalicyl) fumarate (DBBF) allowed selective covalent fixation of each supramolecular polymer species, affording fixed bicyclic monomers, fixed polymer particles, and fixed polymer gels with controlled sizes. These fixed Hb−PEG architectures retained characteristic O₂-binding properties. Overall, this work establishes a supramolecular-to-covalent polymer conversion platform that enables precise structural control in Hb-based polymer architectures, thereby expanding the design space for protein−polymer biomaterials.

Protein engineering has recently emerged as a promising strategy for enhancing the enzymatic recycling of bio-based polymers with the aim of replacing non-degradable petroleum-based plastics with biodegradable ones like poly-l-lactic acid (PLLA). However, a significant challenge exists in the evaluation of the biodegradation efficiency of newly developed enzymes. The precise tracking and continuous rate monitoring of the enzyme-catalyzed hydrolysis remain difficult to achieve with a conventional l-lactate assay kit, which provides only endpoint measurements and is therefore decoupled from the real-time degradation process. To address this issue, we introduce a novel Förster Resonance Energy Transfer (FRET)-based PLLA substrate capable of monitoring real-time PLLA degradation. This was achieved by connecting a highly fluorescent amino carbamoyl coumarin (ACC) dye with a quencher (2,4-dinitrophenyl-l-lysine) via a tetrameric oligo-l-lactate chain. Several fluorescence studies demonstrate that this substrate can effectively detect PLLA-degrading enzyme activity by monitoring increased fluorescence due to enzyme-catalyzed hydrolysis of the oligolactate chain and disruption of the intramolecular FRET system. This substrate can be a potent replacement for the conventional l-lactate assay kit as it allows fast and accurate tracking of the enzyme activity toward PLLA.

Massive hemorrhage and impaired wound healing continue to pose critical clinical challenges, particularly due to the limitations of currently available commercial hemostatic dressings, which often exhibit delayed clot formation, poor regenerative potential, and incomplete biodegradation, leading to secondary inflammation. Here, we developed a hemostatic biosponge from aldehyde-functionalized Colocasia esculenta mucilage (OCO) to address these limitations. The introduction of reactive aldehyde groups forms Schiff's base interactions with amine groups present in blood components, facilitating efficient red blood cell entrapment and accelerated coagulation. In vitro studies demonstrated that the sponge effectively absorbs blood, exhibits blood-clotting ability, and is biocompatible. In vivo studies using a rat liver laceration model showed that the OCO sponge achieved hemostasis within 30 ± 2.4 s, significantly faster than the 102 ± 1.3 s required by a commercial gelatin sponge, highlighting its superior hemostatic performance. Furthermore, in vivo full-thickness skin wound studies confirmed enhanced wound healing, with the OCO-treated group exhibiting 1.10-fold greater wound closure by day 18 compared to the gelatin sponge group and showing gradual resorption without adverse tissue reaction, thereby minimizing the risk of chronic inflammation. Therefore, this engineered OCO biosponge represents a promising biomaterial for bleeding control and skin tissue repair in traumatic conditions.

Wood-based phase-change composites are promising for solar-thermal energy storage and thermal regulation. However, native wood limits phase-change material (PCM) uptake, whereas extensive delignification removes lignin’s intrinsic light-harvesting capacity. We developed a cell−wall nano-engineering approach using aqueous p-toluenesulfonic acid to partially remove hemicellulose and redistribute retained lignin. This treatment increased cell-wall accessibility while preserving the wood's photothermal function. After impregnation with poly(ethylene glycol) impregnation, the resulting composite achieved a melting enthalpy of 154.9 J g⁻¹ and an encapsulation efficiency of 78.5%. It showed no visible leakage at 80 °C and maintained stable thermal-storage performance over 100 heating−cooling cycles (differential scanning calorimetry). Lignin redistribution and reassembly within the cell wall also improved water repellency and moisture resistance. Compared with native- and delignified-wood controls, the composite showed stronger broadband absorption and an apparent photothermal conversion efficiency of 83.2% under two-sun irradiation. This lignin-retaining strategy integrates physical PCM confinement, thermal storage, and intrinsic photothermal conversion without requiring additional light absorbers.