Spectroscopic studies on the interaction between novel polyvinylthiol-functionalized silver nanoparticles with...

Area of Science:

• Biochemistry
• Nanotechnology
• Spectroscopy

Background:

• Silver nanoparticles (Ag-PVT) are increasingly studied for biological applications.
• Understanding nanoparticle-protein interactions is crucial for safety and efficacy.
• Hen-egg white lysozyme is a model protein for studying conformational changes.

Purpose of the Study:

• To investigate the effect of Ag-PVT nanoparticles on hen-egg white lysozyme conformation.
• To elucidate the binding mechanism and stoichiometry between Ag-PVT and lysozyme.
• To assess the impact of Ag-PVT on lysozyme's secondary and tertiary structures.

Main Methods:

• UV-visible absorption spectroscopy
• Intrinsic and synchronous fluorescence spectroscopy
• Resonance Rayleigh scattering (RRS)
• Circular dichroism (CD) spectroscopy

Main Results:

• Ag-PVT nanoparticles induced a hyperchromic shift in lysozyme's UV spectra, indicating complex formation.
• Fluorescence quenching analysis revealed a 1:1 binding ratio and static quenching mechanism.
• CD data showed a decrease in lysozyme's α-helical content, suggesting partial unfolding.
• Synchronous fluorescence spectroscopy indicated perturbation of tryptophan and tyrosine residues, with tryptophan being more affected.
• RRS intensity increased with Ag-PVT concentration, suggesting protein aggregation at higher concentrations.

Conclusions:

• Ag-PVT nanoparticles interact with hen-egg white lysozyme, leading to conformational changes and partial unfolding.
• The interaction follows a static quenching mechanism with a 1:1 binding ratio.
• Ag-PVT nanoparticles can induce protein aggregation at higher concentrations, highlighting potential implications for biological systems.