Gold-nanostar-based SERS substrates for studying protein aggregation processes

Area of Science:

• Biochemistry
• Materials Science
• Spectroscopy

Background:

• Protein aggregation is linked to neurodegenerative diseases like Alzheimer's and Parkinson's.
• Raman spectroscopy is valuable for studying protein conformation and secondary structure changes.
• Developing sensitive methods to monitor protein aggregation is crucial for disease research.

Purpose of the Study:

• To create and characterize a novel surface-enhanced Raman spectroscopy (SERS) substrate for sensitive protein analysis.
• To investigate protein aggregation and conformational changes in bovine serum albumin (BSA) and myoglobin.
• To understand the impact of temperature and solvent modification on protein secondary structure.

Main Methods:

• Synthesis of gold nanostars via a seed-growth method.
• Immobilization of gold nanostars onto glass slides using silanization to create a SERS substrate.
• Characterization of the SERS substrate and assessment of its enhancement factor using crystal violet.
• Analysis of protein aggregation using SERS, including curve fitting, deconvolution of the amide I band, and 2D correlation analysis.

Main Results:

• The developed SERS substrate demonstrated a significant enhancement factor of 5.7 × 10^2.
• The SERS analysis revealed temperature- and solvent-induced changes in the secondary structure of BSA.
• Specifically, a decrease in α-helix and an increase in β-sheet structures were observed in BSA under modified conditions.

Conclusions:

• The gold nanostar-based SERS substrate is effective for sensitive detection of protein aggregation and conformational changes.
• This technique provides insights into the structural alterations of proteins relevant to neurodegenerative disease mechanisms.
• The study highlights the utility of SERS in monitoring protein structural dynamics under various environmental stresses.