Mode of Protein Complexes on Gold Nanoparticles Surface: Synthesis and Characterization of Biomaterials for Hemocompatibility and Preferential DNA Complexation

By using in situ synthesis of gold nanoparticles (Au NPs) in the presence of binary mixtures of cytochrome c (Cyc,c) and bovine serum albumen (BSA) model proteins, we demonstrated a new method of studying protein protein interactions on the surfaces of nanomaterials. Such interactions were simultaneously evaluated and supported by the molecular dynamics studies in terms of protein docking. Both experimental and theoretical studies collectively indicated a strong complexation among Cyc,c and BSA on the surface of Au NPs with a multipoint anchoring mechanism to Au surface. They also highlighted that the Cyc,c BSA complex exhibited much stronger surface adsorption rather than Cyc,c or BSA alone. Biofunctional Au NPs thus obtained were tested for hemocompatibility for their possible applications as drug delivery vehicles in systemic circulation by employing the hemolysis. The hemolysis was done for the Au NPs which were coated with entire mixing range of Cyc,c-BSA mixtures to explore themost appropriate mixing compositions of Cyc,c-BSA mixtures for hemocompatibility. In addition, protein coated Au NPs demonstrated strong complexation with DNA which were significantly pronounced for the Cyc,c-BSA complex coated NPs rather than Cyc,c or BSA alone coated NPs. The Cyc,c-BSA docked complex on Au NP surface behaved like a typical helix turn helix motif because of the size disparity between a much larger BSA and smaller Cyc,c protein that resulted in stronger complexation with DNA in comparison to surface adsorbed Cyc,c or BSA alone. These finding bear important relevance in biotechnology in terms of gene expression and transcription factors.