Release kinetics from nano-inclusion-based and affinity-based hydrogels: A comparative study

Abstract

In this study, we compare the release mechanisms from nanocomposite hydrogels. Liposomes made of different compositions of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1,2-dihexadecanoyl-sn-glycero-3-phosphocholine (DPPC), nanogels made of chitosan-hyaluronic acid association and crosslinked nanogels made of Nisopropylacrylamide (NIPAM) and different ratios of methacrylic acid (MAA) were embedded in acrylamide hydrogels with a model drug, either sulforhodamine B or rhodamine 6G. Liposomes demonstrated the capacity to release their payload over 10 days while NIPAM nanogels and chitosan nanogels released within one or two days. We found that liposomes embedded in hydrogels presented two distinctive release mechanisms, a diffusive burst and a slower “sub-diffusive” release. Both nanogels on the other side presented no observable nor defined affinity-based release mechanism due to presence of salts, completely screening electrostatic interactions. The present work highlights critical points related to the release mechanisms from nanocomposite hydrogels as drug delivery devices or as biomedical tools for tissue engineering or regenerative medicine.