POLYMER-MODIFIED SURFACES FOR BIOMEDICAL APPLICATION

Abstract

In this thesis, three different polymer-modified surfaces have been developed for biomedical applications. In the first part, BSA-functionalized gold nanoparticles (BSA-CS-AuNPs) were prepared for biosensing application by using bovine serum albumin-modified chitosan (BSA-CS) as both reducing and stabilizing agents. To avoid BSA denaturation, a green and non-destructive approach based on sonochemical method was employed for AuNPs synthesis with the need of Tween 80 as steric stabilizing agent and co-reducing agent. The BSA-CS-AuNPs underwent aggregation in the presence of anti-BSA via antigen-antibody specific interactions. In the second part, multifunctional copolymer-stabilized gold nanorods (AuNRs) have been developed for peptide nucleic acid (PNA) delivery. Methacrylic acid (MA) and 2-methacryloyloxyethyl phosphorylcholine (MPC) in the copolymer were used for PNA binding and providing biocompatibility on AuNRs, respectively. The highly stable and nontoxic PNA-immobilized AuNRs were successfully prepared by using thiol-modified and PNA-conjugated copolymer (PNA-Cys-PMAMPC) as stabilizer. As PNA was conjugated with the copolymer by tetrapeptide linker (-Gly-Phe-Leu-Gly-), its release can be induced in the presence of cathepcin B indicating the potential antisense applications of the developed AuNRs-based carriers. In the last part, MPC which is also known to exhibit excellent antifouling property was utilized to prepare dual functional patterned surface having both antifouling and antimicrobial properties for preventing biofilm formation. Pattern of copolymer containing dihydrolipoic acid (DHLA) and MPC backfilled with Ag film showed both bacteria adhesion resistance on MPC area and bacterial killing on Ag lines implying the combined antifouling and antibacterial effects on this patterned surface.