Immobilization of liposomes on temperature-responsive polymer networks cross-linked with poly-L-lysine and grafted onto polypropylene

Abstract

Immobilization of liposomes on implantable/insertable medical devices may be advantageous for the stability of liposomes and the localized release of drugs from the device to prevent/manage pathological processes. This work focuses on the preparation of polymeric systems suitable for the immobilization of drug-free and 5-fluorouracil-loaded liposomes. Polymeric systems, based on N-isopropylacrylamide (NIPAAm) and N-acryloxysuccinimide (NAS), were prepared by γ radiation with three different structures: a binary copolymer grafted onto polypropylene (PP), an interpenetrated polymer network (IPN) grafted onto PP, and an IPN hydrogel; all of them cross-linked with poly-L-lysine. Although liposome immobilization is accompanied by a lost in the 5FU entrapment efficiency, the high extent of the immobilization provides the polymeric systems with a remarkable amount of drug at their surface. These findings point out poly-L-lysine as a suitable component to endow surface-modified devices with ability to host liposomes and thus to develop drug-medical device combination products.