Investigating the Structural Stability of RADA16-I Peptide Conjugated to Gold Nanoparticles

Abstract

RADA 16-I is an amphiphilic peptide which can form macroscopic scaffolds through self-assembly and has found many applications in tissue regeneration and hemostasis. It is still unclear in which conditions this peptide can perform self-assembly more effectively while maintaining its stability. Interaction between peptides and gold surfaces has been increasingly regarded for biotechnological applications. In order to better understand the effect of this conjugation on the application of RADA16-I, properties of peptide-modified gold nanoparticles were studied using circular dichroism, DLS, DSC and UV–Visible imaging to monitor changes in conformation of the conjugated peptide. The bioinformatics studies showed that the peptides exhibit a predominantly helical structure as monomer. UV–Visible spectrum of the gold nanoparticles showed an absorption peak at around 520 nm. Spectral and DLS analyses indicated precision of conjugation and the stronger tendency of conjugated peptide, as compared to its unconjugated form, toward aggregation or self-assembly. CD analysis showed a slight increase in β-strands of the conjugated peptides. Furthermore, DSC data suggested enthalpy-driven nature of the conjugation process minor changes in peptide stability. These findings can help researchers in the design of future nano-biomaterials, such as biosensors, based on β-sheets, scaffolds, and gold nanoparticles. The present study may serve as a scientific basis for improving efficacy and application of peptide as hemostat.