Temperature Dependent and Kinetic Study of the Adsorption of Bovine Serum Albumin to ZnO Nanoparticle Surfaces

摘要

Here, we study the role of temperature for the adsorption of Bovine Serum Albumin to ZnO Nanoparticle Surfaces and the kinetics of the ZnO NPs-BSA corona by using UV-vis absorption, DLS, fluorescence spectroscopy. Structures of the synthesized ZnO NPs are studied by XRD, TEM, and FT-IR measurements. The band gap and crystal size of ZnO suggests the quantum confinement effect. The photoluminescence spectrum of pure ZnO NPs showed shallow deep level blue emission due to various defect states. The Zn-O bond formation was confirmed through Fourier transformed infrared spectroscopic analysis. The crystal unit cell of the nanoparticles is found to be hexagonal. A small red shift of the absorption peak of BSA is observed due to binding of BSA with different concentration of ZnO NPs. The time constants for surface binding and reorganization under four different temperatures showed that the binding decreases and unfolding increases as the temperature increases up to 315 K. Hydrodynamic radius of the bioconjugate under different temperature showed large BSA aggregates at temperature 315 K. The change in energy transfer efficiency (Q(eff)) between ZnO NPs and BSA with time at room temperature was studied. The quenching in the fluorescence emission of tryptophan (Try) residues in the structure of BSA is static in lower temperature and dynamic in higher temperature. The interaction between Try of BSA and ZnO NPs is exothermic, electrostatic and hydrophobic in nature.