The interaction as well as the formation of bioconjugate of Bovine Serum Albumin (BSA) and Zinc Oxide nanoparticles (ZnO NPs) is investigated. The surface binding along with reorganization of BSA on the surface of ZnO NPs forms stable “hard corona.” The time constants for surface binding and reorganization are found to be 1.10 min and 70.68 min, respectively. The close proximity binding of BSA with ZnO NPs via tryptophan is responsible for bioconjugate formation. Fibrillar aggregated structure of BSA is observed due to conformational change of BSA in interaction with ZnO NPs.

In this paper, we have used spectroscopic and electron microscopic analysis to monitor the time evolution of the silver nanoparticles (Ag NP)–human hemoglobin (Hb) corona formation and to characterize the interaction of the Ag NPs with Hb. The time constants for surface plasmon resonance binding and reorganization are found to be 9.51 and 118.48 min, respectively. The drop of surface charge and the increase of the hydrodynamic diameter indicated the corona of Hb on the Ag NP surface. The auto correlation function is found to broaden with the increasing time of the corona formation. Surface zeta potential revealed that positively charged Hb interact electrostatically with negatively charged Ag NP surfaces. The change in α helix and β sheet depends on the corona formation time. The visualization of the Hb corona from HRTEM showed large number of Hb domains aggregate containing essentially Ag NPs and without Ag NPs. Emission study showed the tertiary deformation, energy transfer, nature of interaction and quenching under three different temperatures.Electronic supplementary materialThe online version of this article (doi:10.1186/s40580-017-0122-1) contains supplementary material, which is available to authorized users.

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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 (Qeff) 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.