Viscoelasticity of Fibrous Hydrogels Driven by Dynamic Intrafibrillar Imine Cross-Linking.

Viscoelasticity of biological fibrous networks impacts cell fates and may reflect pathological conditions in vivo. Imine-cross-linked fibrous hydrogels can serve as effective in vitro models for studying viscoelastic properties of biological tissues; however, the specific role of intrafibrillar dynamic covalent bonds in governing hydrogel elasticity and stress relaxation remains unexplored. Here, for fibrous hydrogels derived from cellulose nanocrystals and polyethylene glycol, we systematically varied the content of intrafibrillar imine cross-links to explore their impact on hydrogels' elastic response, stress relaxation, and fibrous structure.

Spheroid-based skin-on-a-chip platform for the evaluation of the toxicity of small molecules and nanoparticles.

Exposure of human skin to chemical agents may lead to skin sensitization, irritation, and corrosion. Time-efficient toxicity screening is currently achieved using skin-on-a-chip models; however, these either lack a multilayer structure characteristic of the skin, or require long fabrication time. Here, we report the development and proof-of-concept application of the microfluidic spheroid-based skin-on-a-chip platform utilizing gravity-driven flow and large arrays of multilayer skin spheroids (MSSs).

Confinement-induced chirality in phase-separated achiral polymer solutions.

Self-organization of polymers in constrained geometries largely determines their applications in high-strength materials, photonics, and electronics. Chiral organization under confinement is well established for polymers with intrinsic molecular chirality; however, it has not been observed for achiral polymers. Here, we report the emergence of chirality in spatially confined solutions of achiral rigid-rod polymers.

Artificially Engineered Nonlinear Circular Dichroism with Chiral Nanoscrolling of 2D Materials.

Nonlinear chiroptical response, particularly nonlinear circular dichroism (CD), holds significant potential for advancing nanotechnology, biophotonics, and molecular imaging. While conventional approaches rely on intrinsic chiral materials, we demonstrate a novel strategy to engineer this effect by transforming achiral two-dimensional (2D) transition-metal dichalcogenides (TMDs) into chiral nanostructures. By scrolling monolayer TMDs into geometrically chiral nanoscrolls, we achieve pronounced nonlinear CD (up to 0.

Colloidal Hydrogel with Staged Sequestration and Release of Molecules Undergoing Competitive Binding.

Competitive binding of distinct molecules in the hydrogel interior can facilitate dynamic exchange between the hydrogel and the surrounding environment. The ability to control the rates of sequestration and release of these molecules would enhance the hydrogel's functionality and enable targeting of a specific task. Here, we report the design of a colloidal hydrogel with two distinct pore dimensions to achieve staged, diffusion-controlled scavenging and release dynamics of molecules undergoing competitive binding.

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.

Intrafibrillar Crosslinking Enables Decoupling of Mechanical Properties and Structure of a Composite Fibrous Hydrogel.

The fibrous network of an extracellular matrix (ECM) possesses mechanical properties that convey critical biological functions in cell mechanotransduction. Engineered fibrous hydrogels show promise in emulating key aspects of ECM structure and functions. However, varying hydrogel mechanics without changing its architecture remains a challenge.

Nanogels designed for cell-free nucleic acid sequestration.

Chronic wounds exhibit over-expression of cell-free deoxyribonucleic acid (cfDNA), leading to a prolonged inflammation and non-healing wounds. Scavenging excessive cfDNA molecules is a promising strategy for chronic wound treatment. Nanoscopic particles act as efficient cfDNA scavengers due to their large surface area, however their efficiency in cfDNA uptake was limited by adsorption solely on the nanoparticle surface.

Luminescence properties, energy transfer and thermal stability of white emitting phosphor Sr(PO):Ce/Tb/Mn for white LEDs.

A series of Sr(PO):Ce/Mn/Tb phosphors were synthesized by a high temperature solid phase method. After introducing Ce as sensitizer in Sr(PO):Ce/Mn, the efficient energy transfer from Ce to Mn was observed and analyzed in detail, and Sr(PO):Ce/Mn was demonstrated to be color tunable, changing from blue to orange red. In addition, Tb ion, which mainly emits green light, was further added into the Sr(PO):Ce/Mn.

Stimulus-Responsive Nanoconjugates Derived from Phytoglycogen Nanoparticles.

Plant-derived phytoglycogen nanoparticles (PhG NPs) have the advantages of size uniformity, dispersibility in water, excellent lubrication properties, and lack of cytotoxicity; however, their chemical functionalization may lead to loss of NP structural integrity. Here, we report a straightforward approach to the generation of PhG NP conjugates with biologically active molecules. Hydrogen bonding of bovine serum albumin with electroneutral PhG NPs endows them with additional ligand binding affinity and enables the electrostatically governed attachment of methotrexate (MTX), a therapeutic agent commonly used in the treatment of cancer and arthritis diseases, to the protein-capped NPs.

Phytoglycogen Nanoparticles: Nature-Derived Superlubricants.

Phytoglycogen nanoparticles (PhG NPs), a single-molecule highly branched polysaccharide, exhibit excellent water retention, due to the abundance of close-packed hydroxyl groups forming hydrogen bonds with water. Here we report lubrication properties of close-packed adsorbed monolayers of PhG NPs acting as boundary lubricants. Using direct surface force measurements, we show that the hydrated nature of the NP layer results in its striking lubrication performance, with two distinct confinement-controlled friction coefficients.

Impact of phase separation morphology on release mechanism of amorphous solid dispersions.

Amorphous solid dispersions (ASDs) can phase separate in the gel phase during dissolution, lowering the chemical potential and thus the driving force for drug release. The purpose of this study is to explore the connection between amorphous phase separation in the hydrated ASD and its resulting release rate. Poorly soluble model compounds - indomethacin (IND) and ritonavir (RTV) - were formulated as ASDs using PVP as carrier.