Dynamic granular hydrogels to assess pancreatic cancer cell fate

Abstract

Granular hydrogels are an emerging biomaterial platform that is increasingly used in biomedical applications, including therapeutic delivery and tissue regeneration. Assembled from micron-scale hydrogel particles through physical assembly or chemical cross-linking, granular hydrogels possess micro- and macroscopic pores that facilitate molecular transport and cell migration. However, current granular hydrogels are typically fabricated with defined features (stiffness, porosity, compositions, etc.) that do not recapitulate the dynamic nature of native tissues, including the tumor microenvironment. To address this challenge, we have developed dynamic granular hydrogels formed by gelatin-norbornene-carbohydrazide (GelNB-CH) microgels. GelNB-CH microgels were first prepared from a microfluidic droplet generator coupled with the rapid thiol-norbornene photo-click gelation. The collected microgels were annealed via inverse electron-demand Diels-Alder (iEDDA) click reaction to form granular hydrogels, which were dynamically stiffened via hydrazone bonding. Notably, adjusting the concentration of stiffening reagent (i.e., oxidized dextran or oDex) allowed for the dynamic stiffening of the granular hydrogels without affecting the scaffold's void fraction. Pancreatic cancer-associated fibroblasts (CAFs) seeded in the granular hydrogels spread rapidly throughout the scaffold. Furthermore, dynamic stiffening of the granular hydrogels led to upregulation of markers associated with epithelial-mesenchymal transition (EMT). This work enhances the design of granular hydrogels, offering a highly adaptable biomaterial platform for in vitro cancer modeling.