Collagen/functionalized cellulose nanofibril composite aerogels with pH-responsive characteristics for drug delivery system.

In this work, carboxylated and amination modified cellulose nanofibrils (CNFs) were fabricated via the TEMPO catalytic oxidation system and diethylenetriamine, and collagen composite aerogels were fabricated through a simple self-assembly pretreatment and directional freeze-drying technology. Morphology analysis showed that the collagen composite aerogels had distinct layered-oriented double network structures after the self-assembly pretreatment. The intermolecular interactions between the collagen fibrils and functionalized CNFs (fCNFs) on the structures and properties of the composite aerogels were also examined through various characterization techniques. Water contact angle tests demonstrated the pH-responsive characteristics of the collagen/fCNF composite aerogels. Using 5-fluorouracil as the model drug, the pH-response mechanism was revealed. These results indicated that the collagen/fCNF composite aerogels exhibited excellent pH-responsive drug release capacities. Therefore, these pH-responsive collagen composite aerogels might have potential applications in industrial production in the biomedical, drug delivery, and tissue engineering fields.