Protein Conjugation with Gold Nanoparticles: Spectroscopic and Thermodynamic Analysis on the Conformational and Activity of Serum Albumin

Gold nanoparticles (GNPs) have large scale application in many important areas with potential exposure to the environment or organisms during their life cycle. This article identifies the binding mechanism of cetyltrimethyl ammonium bromide (CTAB) coated GNPs to human serum albumin (HSA) utilizing fluorescence, UV-vis, circular dichroism (CD) spectroscopy and isothermal titration calorimetry (ITC) techniques. The fluorescence research presented the intrinsic fluorescence of HSA was dampened due to the adding of GNPs under a static dampening process. The thermodynamic study further showed the binding interaction was controlled by van der Waals forces or hydrogen bonds (Delta H and Delta S are -3.06x10(7) J.mol(-1) and -1.03x10(5) J.mol(-1).K-1, respectively) for the most part. On the other hand, UV-vis, CD spectroscopy and esterase-like activity studies confirmed the conformational changes and activity reduction of HSA. This research presented reasonable models, which facilitate our understanding of the transporting, circulation and toxic effects of GNPs after spreading into human blood.