title: Comprehensive Multispectroscopic Analysis on the Interaction and Corona Formation of Human Serum Albumin with Gold/Silver Alloy Nanoparticles.
abstract: In the present investigation, we have systematically studied the binding mechanism of model protein human serum albumin (HSA) with gold/silver alloy nanoparticles (Au/Ag NPs) using multiple spectroscopic techniques. Absorption spectral studies of Au/Ag NPs in the presence of increasing concentrations of HSA resulted in a slight red shift of the surface plasmon resonance band (SPR) of Au/Ag NPs, suggesting changes in the refractive index around the nanoparticle surface owing to the adsorption of HSA. The results from high-resolution transmission electron microscopy (HR-TEM), dynamic light scattering (DLS), and zeta potential analysis substantiated the formation of a dense layer of HSA on the surface of Au/Ag NPs. The formation of a ground-state complex between HSA and Au/Ag NPs was evident from the outcome of the steady-state emission titration experiments of the HSA-Au/Ag NPs system. The binding parameters computed from corrected emission quenching data revealed that HSA exhibited a significant binding affinity toward Au/Ag NPs. The identical fluorescence lifetime values of HSA and HSA-Au/Ag NPs from time-resolved fluorescence spectroscopic analysis further authenticated the findings of steady-state emission measurements. The formation of HSA corona on the Au/Ag NPs surface was established on the basis of experimental quenching data and theoretical values. The occurrence of partial unfolding of HSA upon its interaction with the Au/Ag NPs surface was established by using an extrinsic fluorophore 1-anilino-8-naphthalenesulfonic acid (ANS). Absorption, Fourier transform infrared (FT-IR), Raman, circular dichroism (CD), and excitation-emission matrix (3D) spectral studies were also carried out to explore Au/Ag NPs-induced tertiary and secondary conformational changes of HSA. The influence of Au/Ag NPs on the esterase-like activity of HSA was established by probing the hydrolysis of p-nitrophenyl acetate.
authors.affiliation: Department of Chemistry, Bharathiar University, Coimbatore- 641046, India.
authors.forename: Arumugam
authors.initials: A
authors.lastname: Selva Sharma
authors.affiliation: Department of Chemistry, Bharathiar University, Coimbatore- 641046, India.
authors.forename: Malaichamy
authors.initials: M
authors.lastname: Ilanchelian
mesh_terms: D000497:Alloys / Q000737:chemistry*; D004950:Esterases / Q000378:metabolism; D006046:Gold / Q000737:chemistry* / Q000494:pharmacology; D006801:Humans; D053768:Metal Nanoparticles / Q000737:chemistry*; D008958:Models, Molecular; D011485:Protein Binding; D000066970:Protein Corona / Q000737:chemistry* / Q000378:metabolism; D017433:Protein Structure, Secondary / Q000187:drug effects; D017434:Protein Structure, Tertiary / Q000187:drug effects; D012709:Serum Albumin / Q000737:chemistry* / Q000378:metabolism; D012834:Silver / Q000737:chemistry* / Q000494:pharmacology; D013057:Spectrum Analysis
chemical_list: D000497:Alloys; D000066970:Protein Corona; D012709:Serum Albumin; D012834:Silver; D006046:Gold; D004950:Esterases