Supporting Information for "Collagen type II dynamics and assembly in anisotropic porous polyacrylamide hydrogels "

Inspired by liquid crystallinity and hierarchical organization in natural systems, we fabricate anisotropic polyacrylamide (PAAm) networks by templating polymerization around Disodium Cromoglycate (DSCG) liquid crystal phases. These anisotropic porous networks act as scaffolds that guide collagen fiber alignment, recapitulating key aspects of extracellular matrix (ECM) organization in biological tissues. The pore morphology and characteristic length scales are tuned by varying the modulus of the PAAm network, while polymerization at different temperatures induces distinct DSCG phases and corresponding pore anisotropies. Network architecture is characterized by confocal microscopy. The hydrogels are subsequently swollen in 1 mg/mL collagen solutions prepared in 0.12 M HCl, followed by fibril formation triggered in a neutral pH buffer. Collagen localization within the pore walls and voids are visualized by confocal microscopy, and its dynamics are quantified using Differential Dynamic Microscopy (DDM). As pore size decreases, collagen mobility is progressively slowed and the distribution within the gel depends on the morphology. In networks polymerized at 30 °C, collagen localizes exclusively within the pore walls. In contrast, in gels polymerized at −20 °C collagen freely diffuses and assembles within the anisotropic pores, yielding highly aligned structures at higher collagen concentrations. Together, these results provide insight into self-assembly within crowded, elastic environments and establish a strategy for engineering biomimetic ECM scaffolds.