Synthesis of collagen-grafted polyacrylamide hydrogel for biomedical applications

The mechanical properties of extracellular matrix (ECM) mimicked by hydrogels have been extensively utilized in investigating cell-ECM interactions, employing materials such as polyacrylamide gels and polydimethylsiloxane gels. However, these materials typically require the coupling of ECM proteins to provide cell adhesion ligands, leading to complex procedures and high costs. In this study, we present a novel approach for fabricating a double network hydrogel (PAAm-Col) that combined the stable and tunable mechanical properties of the PAM network with cell-adhesive functionalities provided by the collagen network. By adjusting the ratio of acrylamide to collagen, the hydrogel's elastic modulus could be tailored while maintaining superior light transmittance, hydrophilicity, and stability. Subsequent in vitro cell studies, cryopreserved embryos culture and in vivo subcutaneous implantation of the hydrogel in mice demonstrated its efficacy in facilitating cell proliferation under varying stiffness conditions. The gels exhibited excellent biocompatibility, minimal inflammatory response, and potential for drug delivery. Furthermore, the substitution of bovine tendon type I collagen with recombinant human type I collagen in the preparation process yielded hydrogels that retained exceptional biocompatibility. This work demonstrated that PAAm-Col is a novel biomaterial for various biomedical applications.