Gold Nanoparticles Size Determines The Interaction With Protein

As one of the most common nanomaterials,gold nanoparticles(AuNPs)have been paid more attentions with their unique properties,such as small-scale effects,optical effects,surface effects,excellent stability and biocompatibility.Recently,more researchers focused on the application studies of AuNPs for their broad application prospects in food safety testing,industrial catalysis,cell imaging and biomedical fields.As the basic material of life activity,protein not only participate in gene transfer and expression,but also can be used as enzyme to involve in all kinds of chemical reactions in vivo.At the same time,protein is the fundamental component of cytoskeleton structure,and plays an extremely important role in life process.Therefore,the study on the interaction of AuNPs with proteins has great significance to fully understand the interaction nature of nanomaterials with proteins,and also has useful guidance for the safe and effective application of AuNPs in the fields of biology and medicine.As the part of funded project for the National Natural Science Foundation of China(Nos.21303043,21173071),we selected human serum albumin(HSA)and different sizes of Au NPs as the research objects in this paper.The interaction of HSA with different size of AuNPs were studied by using UV-vis absorption spectroscopy,fluorescence spectroscopy,synchronous fluorescence spectroscopy,circular dichroism(CD),transmission electron microscope(TEM)and dynamic light scattering(DLS)techniques.The Hill coefficients and the binding constants for the binding systems were estimated with the analysis of fluorescence spectrum data.The results showed that the binding constants increase gradually with the increase of the size of AuNPs.Simultaneously,the results of UV-vis absorption spectroscopy implied the formation of the ground state complexes in the binding processes.Moreover,the conformational changes of HSA were analyzed by using synchronous fluorescence spectroscopy and CD.The quantitative calculation results indicated that the size of AuNPs has little impact on the protein conformation.With the observations of TEM and DLS,the thickness of protein corona on the surface of AuNPs was systematically and quantitatively investigated.The results illustrated that the size of AuNPs has greater influence on the thickness of protein corona.Additionally,the changes of AuNPs aggregation behavior mediated by protein were evaluated,and the relationship of AuNPs aggregation behavior with their size was also analyzed using UV-vis absorption spectroscopy and DLS techniques.The results suggested that small size of AuNPs more easily aggregates in the presence of HSA.The present work will be helpful for the deep understanding of the biological effect of AuNPs,and useful for the development of their application studies.