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.

Carbon Quantum Dot-Anchored Bismuth Oxide Composites as Potential Electrode for Lithium-Ion Battery and Supercapacitor Applications

“…The negligible difference in the fluorescence lifetimes of the CQD and the CQD–Bi 2 O 3 composite clearly suggests the formation of nonfluorescent ground-state complex and involvement of static quenching mechanism. 32 It is well known that the formation of a ground-state complex between the fluorophore and metal oxide materials cannot induce changes in the fluorescence lifetimes of the fluorophore. 33 Thus, it is believed that the observed emission quenching in the case of the CQD–Bi 2 O 3 composite is primarily due to the static quenching mechanism.…”

Studies on binding of single‐stranded DNA with reduced graphene oxide–silver nanocomposites

“…The well known Stern–Volmer (2) [47] was used to analyse the quenching type (static or dynamic) for the ssDNA–rGO–AgNCs system where F and F 0 are the fluorescence intensities of ssDNA in the presence and absence of rGO–AgNCs (quencher), respectively. K sv and K q are the Stern–Volmer and biomolecular quenching constants, respectively.…”

Interactions of Self-Assembled Bletilla Striata Polysaccharide Nanoparticles with Bovine Serum Albumin and Biodistribution of Its Docetaxel-Loaded Nanoparticles

“…Fluorescence quenching may be due to two mechanisms, static quenching or dynamic quenching [28,29]. To clarify the quenching mechanism, static and dynamic processes were analyzed by the Stern–Volmer Equation (5).…”

“…The interaction may influence the structure and function of protein [26] as well as physicochemical characteristics of nanoparticles such as surface structure, shape, and aggregation [27]. However, the investigations on their interaction have rarely been reported [28,29,30]. Generally, bovine serum albumin is employed as a model protein due to its homologous structure with human serum albumin [31].…”