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Abstract Hydrogels are widely used in tissue engineering, but conventional homogeneous polymerization often creates dense matrices that hinder cell migration and restrict extracellular matrix production. The motivation of this project was to overcome these limitations by developing a heterogeneously crosslinkable hydrogel platform that enables both cell migration and matrix deposition. We present a two-step heterogeneous polymerization approach that introduces spatial variations in matrix density, producing tunable, cell-sized pores that promote migration, proliferation, and matrix synthesis. As an implementation, gelatin was pre-assembled into microribbon-like building blocks using a dynamic molding process, methacrylated to introduce crosslinkable groups, chemically modified, washed, and freeze-dried. Upon rehydration, the ribbons formed a moldable paste that could be mixed with cells and photo-crosslinked into scaffolds within situ–formed, cell-sized pores. The main novelty of this method is the introduction of chemical modifications with methacrylic anhydride (MAA), acetic anhydride (AceA), and succinic anhydride (SucA), which enable a controlled two-step heterogeneous polymerization and allow independent tuning of scaffold microstructure, mechanics, and degradation. AceA reduced crosslink density and accelerated degradation, whereas SucA promoted swelling, enhanced mechanical strength, and slowed degradation. Cell studies revealed that SucA-modified scaffolds supported superior adhesion and proliferation compared to AceA-modified and unmodified controls. Such work may significantly impact the design of next-generation scaffolds by providing a versatile platform that integrates structural, mechanical, and biochemical control for regenerative medicine applications. 

ABSTRACT We investigate the formation of poly(L‐lactic acid) (PLLA) nanoparticles using a green solvent, propylene carbonate (PC), via a combination of nonsolvent‐induced phase separation (NIPS) and temperature‐induced phase separation (TIPS). Water (W) is used as the nonsolvent to induce liquid/liquid phase separation (LLPS) of the PLLA/PC solution at high temperature. Reducing the solution temperature can induce a second LLPS, followed by PLLA crystallization. Three types of polymer nanoparticles (PNPs), including PLLA single crystals, spherical Ouzo crystalsomes, and sheaf‐like crystals named cascade PNPs (CasPNPs), have been observed. The crystalline structure and thermal behavior of the PNPs have been investigated using Wide‐Angle X‐ray diffraction, Fourier Transform Infrared Spectroscopy, and Differential Scanning Calorimetry. A PNP morphology map of the PLLA/PC/W ternary system has been established. The complex PNP morphology is attributed to the two levels of cascade LLPS coupled with confined PLLA crystallization. Our results demonstrate that LLPS directs the formation of both PLLA spherical particles and curved single crystals, with improved crystallization kinetics. 

Toughness reflects extensibility, which is critical for. accommodating electrode volume changes in batteries, primarily due to thermal expansion. However, polymer toughness has received less attention for battery dendrite suppression than polymer modulus. Inspired by rubber chemistry, here, we investigate the polymer network structure, ion conductivity, and mechanical properties of cross-linked poly(glycidyl methacrylate) (PGMA)−poly(ethylene glycol) (PEG) networks containing sodium bis (fluorosulfonyl imide) (NaFSI) salt. We explore two PGMA:PEG molar ratios (1:1 and 5:1), and three salt concentrations (Na+ to EO: (r) = 0.01, 0.0625, and 0.25), and observe that lower PGMA content results in higher hydrophilicity and lower cross-link density. These properties translate to a total ion conductivity of 0.5 × 10−4 S/cm at 25 °C and nearly 0.5 × 10−3 S/cm at 65 °C for the optimum composition (1:1) and salt concentration (r= 0.0625). The polymer electrolytes exhibit good mechanical properties (elongation at strain between 125 and 140%, Young’s modulus between 0.3 and 0.7 MPa, and toughness between 0.25 and 0.70 MJ/m3). By virtue of their high ion conductivity and toughness, these comb−chain network SPEs have the potential to exhibit excellent cycling performance in emerging sodium metal batteries.