Strong, Multifaceted Guanidinium-Based Adhesion of Bioorganic Nanoparticles to Wet Biological Tissue

Tunable Wet Adhesion of Sprayable Microgel Glues Driven by a Phase Transition in Polymer Networks

With the emergence of human-computer interaction and related fields, how to realize tunable adhesion on wet and soft materials has become an important issue. In this letter, we propose a strategy for tunable wet adhesion by leveraging the phase transition of polymeric nanoparticles to achieve dynamic, multiscale, and multifactorial synergistic modulation. The strategy is validated by using stimuli-responsive polymer microgel dispersions as sprayable glues, which can switch between swollen and deswollen states through phase transitions, thereby tuning interfacial water molecules. This process dynamically tunes microscopic molecular interactions and the mesoscopic contact area between microgel nanoparticles and the substrate surface, as well as the cohesion within interfacial microgel layers. As a result, adhesion is enhanced in the swollen state, reaching about 373 N m-1, while it is weakened in the deswollen state due to water release. The tunable wet adhesion is reproducible, making the sprayable microgel glues of potential interest for applications (e.g., in hydrogel-based sensors for human motion detection).

Self-Healing Scaffolding Technology with Strong, Reversible Interactions under Physiological Conditions for Engineering Marbled Cultured Meat

Cultured meat offers a sustainable alternative to animal farming, with the potential to reduce environmental impacts and improve food security. However, recapitulating natural meat marbling remains a significant challenge. This study presents a straightforward technology for achieving precise marbling patterns in large-scale cultured meat using self-healing hydrogels containing boronic acid-conjugated chitosan. Unlike conventional hydrogels, which require nonphysiological conditions for strong, reversible bonding, our system achieves robust reversible bonding at neutral pH through a unique mechanism: the nucleophilic groups of chitosan facilitate boronic acid-diol bond formation, exhibiting half the strength of a typical covalent bond, as demonstrated by nanomechanics analysis. The hydrogels form dual reversible networks of boronic acid-diol and hydrogen bonds, enabling self-healing and tunable stiffness. Biocompatibility studies confirm that they support the growth of mouse-derived cells and bovine-derived primary muscle cells. Each hydrogel variant optimizes mechanotransduction for the distinct requirements of fat or muscle cell culture and differentiation. This self-healing scaffolding technology enables the seamless assembly of muscle and fat monocultures into centimeter-thick meat with micrometer-scale marbling patterns, tailoring organoleptic properties and nutritional profiles without the need for meat glues or processing equipment.

Fabricating Remote-Controllable Dynamic Ionomer/CNT Networks via Cation-π Interaction for Multi-Responsive Shape Memory and Self-Healing Capacities

Shape memory polymers (SMPs) with remotely controllable triggering capabilities are crucial for actuating applications in biomedical and aeronautic devices. This work presents a novel ionomer/carbon nanotube (CNT) composite network with exceptional remotely controllable shape memory effects (SMEs) and self-healing capabilities. By integrating quaternary ammonium (QA) units covalently bonded to crystalline polycaprolactone (PCL) segments through a chain extension reaction, we not only enabled the formation of ion clusters that act as netpoints in PCLQA ionomers to achieve superior SMEs, but also facilitated the generation of cation-π interactions when the multiresponsive CNTs were incorporated into the PCLQA ionomer matrix. This resulted in a robust physical PCLQA@CNT network stabilized by ionic clusters and cation-π interactions, along with significantly enhanced CNT dispersion. The PCLQA@CNT composites demonstrated remarkably improved mechanical performance (tensile strength, σb > 40 MPa; elongation at break, εb > 1900%), excellent thermally induced SME (shape fixity ratio of 99.6% and shape recovery ratio of 92.3%), and exceptional antibacterial effects (>99% against Escherichia coli and Staphylococcus aureus). Furthermore, the physical dynamic interactions endowed PCLQA@CNT networks with reproducibility and welding capability. The remotely controllable shape memory and self-healing behaviors via NIR and electrical stimulation were verified and demonstrated. This work paves the way for developing remotely controllable shape memory materials for advanced intelligent devices and applications.

Self-Exfoliated Guanidinium Covalent Organic Nanosheets as High-Capacity Curcumin Carrier

Drug administration is commonly used to treat chronic wounds but faces challenges such as poor bioavailability, instability, and uncontrollable release. Existing drug delivery platforms are limited by chemical instability, poor functionality, complex synthesis, and toxic by-products. Presently, research efforts are focused on developing novel drug carriers to enhance drug efficacy. Guanidinium Covalent Organic Nanosheets (gCONs) offer promising alternatives due to their high porosity, surface area, loading capacity, and ability to provide controlled, sustained, and target-specific drug delivery. Herein, we successfully synthesized self-exfoliated gCONs using a Schiff base condensation reaction and embedded curcumin (CUR), a polyphenolic pleiotropic drug with antioxidant and anti-inflammatory properties, via the wet impregnation method. The BET porosimeter exhibited the filling of gCON pores with CUR. Morphological investigations revealed the formation of sheet-like structures in gCON. Culturing human dermal fibroblasts (hDFs) on gCON demonstrated cytocompatibility even at a concentration as high as 1000 µg/mL. Drug release studies demonstrated a controlled and sustained release of CUR over an extended period of 5 days, facilitated by the high loading capacity of gCON. Furthermore, the inherent antioxidant and anti-inflammatory properties of CUR were preserved after loading into the gCON, underscoring the potential of CUR-loaded gCON formulation for effective therapeutic applications. Conclusively, this study provides fundamental information relevant to the performance of gCONs as a drug delivery system and the synergistic effect of CUR and CONs addressing issues like drug bioavailability and instability.

Synthetic polypeptides inhibit nucleic acid-induced inflammation in autoimmune diseases by disrupting multivalent TLR9 binding to LL37-DNA bundles

Complexes of extracellular nucleic acids (NAs) with endogenous proteins or peptides, such as LL37, break immune balance and cause autoimmune diseases, whereas NAs with arginine-enriched peptides do not. Inspired by this, we synthesize a polyarginine nanoparticle PEG-TK-NPArg, which effectively inhibits Toll-like receptor-9 (TLR9) activation, in contrast to LL37. To explore the discrepancy effect of PEG-TK-NPArg and LL37, we evaluate the periodic structure of PEG-TK-NPArg-NA and LL37-NA complexes using small-angle X-ray scattering. LL37-NA complexes have a larger inter-NA spacing that accommodates TLR9, while the inter-NA spacing in PEG-TK-NPArg-NA complexes mismatches with the cavity of TLR9, thus inhibiting an interaction with multiple TLR9s, limiting their clustering and damping immune induction. Subsequently, the inhibitory inflammation effect of PEG-TK-NPArg is proved in an animal model of rheumatoid arthritis. This work on how the scavenger-NA complexes inhibit the immune response may facilitate proof-of-concept research translating to clinical application.

Next-generation all-organic composites: A sustainable successor to organic-inorganic hybrid materials

This Review presents an overview of all-organic nanocomposites, a sustainable alternative to organic-inorganic hybrids. All-organic nanocomposites contain nanocellulose, nanochitin, and aramid nanofibers as highly rigid reinforcing fillers. They offer superior mechanical properties and lightweight characteristics suitable for diverse applications. The Review discusses various methods for preparing the organic nanofillers, including top-down and bottom-up approaches. It highlights in situ polymerization as the preferred method for incorporating these nanomaterials into polymer matrices to achieve homogeneous filler dispersion, a crucial factor for realizing desired performance. Furthermore, the Review explores several applications of all-organic nanocomposites in diverse fields including food packaging, performance-advantaged plastics, and electronic materials. Future research directions-developing sustainable production methods, expanding biomedical applications, and enhancing resistance against heat, chemicals, and radiation of all-organic nanocomposites to permit their use in extreme environments-are explored. This Review offers insights into the potential of all-organic nanocomposites to drive sustainable growth while meeting the demand for high-performance materials across various industries.

Assessment of Cellulose Nanofiber-Based Elastase Biosensors to Inflammatory Disease as a Function of Spacer Length and Fluorescence Response

Inflammatory disease biomarker detection has become a high priority in point-of-care diagnostic research in relation to chronic wounds, with a variety of sensor-based designs becoming available. Herein, two primary aspects of biosensor design are examined: (1) assessment of a cellulose nanofiber (CNF) matrix derived from cotton ginning byproducts as a sensor transducer surface; and (2) assessment of the relation of spacer length and morphology between the CNF cellulose backbone and peptide fluorophore as a function of sensor activity for porcine pancreatic and human neutrophil elastases. X-ray crystallography, specific surface area, and pore size analyses confirmed the suitability of CNF as a matrix for wound care diagnostics. Based upon the normalized degree of substitution, a pegylated-linker connecting CNF transducer substrate to peptide fluorophore showed the greatest fluorescence response, compared to short- and long-chain alkylated linkers.

Adsorptive chito-beads for control of membrane fouling

Chitosan has excellent antimicrobial, adsorption, heavy metal removal, and adhesion properties, making it a good substitute for microplastic-based cleaners. Here, chitosan microbeads (chito-beads) of various sizes ranging from 32 μm to 283 μm were prepared via emulsion using a liquid on oil method and the feasibility of using them as an essential constituent in a chemical cleaning solution for a reverse-osmosis (RO) membrane-fouling-control process was assessed. Prior to the assessment the cleaning efficiency of a solution containing chito-beads, the interaction energy between chitosan and a representative organic foulant (humic acid (HA)) in a RO membrane fouling was analyzed using colloidal atomic force microscopy, and the strongest attraction between chitosan and HA was observed in an aqueous solution. When comparing the membrane cleaning efficiency of cleaning solutions with and without chito-beads, smaller chito-beads (32 μm and 70 μm) were found to have higher cleaning efficiency. Applications of chito-beads to the membrane cleaning process can enhance the cleaning efficiency through the physicochemical interaction with organic foulants. This study can widen the use of chito-beads as an additive to membrane chemical cleaning solutions to control membrane fouling in other membrane processes as well.

From Nature-Sourced Polysaccharide Particles to Advanced Functional Materials

Polysaccharides constitute over 90% of the carbohydrate mass in nature, which makes them a promising feedstock for manufacturing sustainable materials. Polysaccharide particles (PSPs) are used as effective scavengers, carriers of chemical and biological cargos, and building blocks for the fabrication of macroscopic materials. The biocompatibility and degradability of PSPs are advantageous for their uses as biomaterials with more environmental friendliness. This review highlights the progresses in PSP applications as advanced functional materials, by describing PSP extraction, preparation, and surface functionalization with a variety of functional groups, polymers, nanoparticles, and biologically active species. This review also outlines the fabrication of PSP-derived macroscopic materials, as well as their applications in soft robotics, sensing, scavenging, water harvesting, drug delivery, and bioengineering. The paper is concluded with an outlook providing perspectives in the development and applications of PSP-derived materials.

Revealing the Control Mechanisms of pH on the Solution Properties of Chitin via Single-Molecule Studies

Chitin is one of the most common polysaccharides and is abundant in the cell walls of fungi and the shells of insects and aquatic organisms as a skeleton. The mechanism of how chitin responds to pH is essential to the precise control of brewing and the design of smart chitin materials. However, this molecular mechanism remains a mystery. Results from single-molecule studies, including single-molecule force spectroscopy (SMFS), AFM imaging, and molecular dynamic (MD) simulations, have shown that the mechanical and conformational behaviors of chitin molecules show surprising pH responsiveness. This can be compared with how, in natural aqueous solutions, chitin tends to form a more relaxed spreading conformation and show considerable elasticity under low stretching forces in acidic conditions. However, its molecular chain collapses into a rigid globule in alkaline solutions. The results show that the chain state of chitin can be regulated by the proportions of inter- and intramolecular H-bonds, which are determined via the number of water bridges on the chain under different pH values. This basic study may be helpful for understanding the cellular activities of fungi under pH stress and the design of chitin-based drug carriers.

Covalent Immobilization of Natural Biomolecules on Chitin Nanocrystals

As a highly crystalline and renewable natural polymer nanomaterial, chitin nanocrystals (ChNCs) have attracted intense interest in the biomedical field. The structure of a ChNC is composed of an acetylglucosamine unit containing two hydroxyl groups and an acetyl group. The acetyl group can be converted to the active amino group through deacetylation, which is under the condition of maintaining the rod-like morphology and high crystalline property and is beneficial for the following modification and potential application. We investigated the relationship between different treatments and varied crystallinities of the modified ChNC, which obtained surface amino groups and aldehyde groups and retained high crystallinity. The natural biomolecules were covalently immobilized on the surface of the ChNC. The etherification was performed based on the hydroxyl groups. Based on the amino groups and the aldehyde groups, the carboxyamine and Knoevenagel condensation reactions were realized on ChNCs. Finally, natural biomolecule-modified ChNCs showed no or low cytotoxicity, antibacterial properties, and high antioxidant properties, which extended their potential biomedical applications.

Masterbatch of Chitosan Nanowhiskers for Preparation of Nylon 6,10 Nanocomposite by Melt Blending

Composite materials have been extensively studied to optimize properties such as lightness and strength, which are the advantages of plastics. We prepared a highly concentrated (30 wt %) nylon/chitosan nanowhisker (CSW) masterbatch by blending nylon 6,10 and CSW by solvent casting to achieve high dispersion efficiency while considering an industrial setting. Subsequently, 0.3 wt % nylon/CSW nanocomposites were prepared with a large quantity of nylon 6,10 via melt blending. During preparation, the materials were stirred in the presence of formic acid at different times to investigate the effect of stirring time on the structure of the CSW and the physical properties of the composite. The formation of nanocomposites by the interactions between nylon and CSW was confirmed by observing the change in hydrogen bonding using FT-IR spectroscopy and the rise in melting temperature and melting enthalpy through differential scanning calorimetry. The results demonstrated increases in complex viscosity and shear thinning. The rheological properties of the composites changed due to interactions between CSW and nylon, as indicated by the loss factor. The mechanical properties produced by the nanocomposite stirred for 1.5 h were superior, suggesting that formic acid caused minimal structural damage, thus verifying the suitability of the stirring condition.