Effect of negative functionalisation of gold nanorods on conformation and activity of human serum albumin

Abstract

The theranostic applications of gold nanorods (AuNRs) are limited due to the presence of cytotoxic cetrimonium bromide (CTAB) stabiliser, leading to the instigation of alternate stabilisers like negatively charged polystyrene sulphonate (PSS). Despite previous reports suggesting the impact of PSS-AuNRs on cells, their effect on the most abundant protein in plasma, i.e. human serum albumin (HSA), has not been studied before. Hence, the impact of PSS-AuNRs on HSA was thoroughly examined using varied spectroscopic techniques. The absorbance and fluorescence spectroscopic findings suggested the extent of ground-state complexation and tryptophan domain disruptions of HSA for different AuNR concentrations, which were also suggested based on size measurements and activation energy calculations for complex formation. Modifications in the hydrophobic environment of HSA were evaluated using synchronous fluorescence, whereas the secondary structural damages were explained using circular dichroism (CD) and FTIR analyses. Additional studies to analyse protein denaturation, fibrillation, esterase activity, and free thiol were carried out to understand structural and functional changes. The study suggested that PSS-AuNRs showed concentration-dependent alterations in HSA structure, but the extent of protein toxicity was considerably lesser for PSS-AuNRs of similar dimensions compared to the data available for CTAB-AuNRs; thus, highlighting that PSS-AuNRs could be safer for biomedical applications.

Effect of Azo Dye Red 2G on Human Gamma Globulin using Multi-Spectroscopic and Docking Studies

“…red 2G (1) 0.0, (2) 0.2, (3) 0.4, (4) 0.6, (5 These results indicated that the microenvironment around the amino acid residues in HGG remains unchanged upon the interaction with R2G and a lack of significant conformational changes in the protein structure [14]. An increase in the absorbance of HGG is due to the formation of a ground-state combination between red 2G and HGG [15]. The Benesi-Hildebrand (B-H) plot was formed using the changes in absorbance intensity of HGG in the presence of R2G.…”

Impact of Surface Charge-Tailored Gold Nanorods for Selective Targeting of Mitochondria in Breast Cancer Cells Using Photodynamic Therapy

“…Further, the surface charge of positively charged gold nanorods was modified into a negative charge by poly­(sodium 4-styrene sulfonate) (PSS). , The polyelectrolyte coating renders biocompatibility and stability to GNRs for various applications. , The excitation spectra of PSS-CTAB@GNRs showed a blue shift after the electrolyte coating (SI, Figure e). The FTIR analysis confirmed the existence of a sharp peak at 1500 cm –1 , confirming the presence of C–C stretching vibrations of PSS.…”