Colorimetric determination of islet amyloid polypeptide fibrils and their inhibitors using resveratrol functionalized gold nanoparticles

The article describes the preparation of gold nanoparticles functionalized with resveratrol (Res-AuNPs) in a single step and by integrating synthesis and modification. By using Res-AuNPs, we have established a colorimetric method for the determination of fibrillar islet amyloid polypeptides (IAPP) and its inhibitors. It is based on the specific recognition of resveratrol by IAPP fibrils. This results in a decrease in the concentration of Res-AuNPs in the supernatant and a corresponding reduction in absorbance at 537 nm. This finding was exploited to design a simple and sensitive colorimetric assay for IAPP fibrils. The analytical range extends from 30 to 400 mu M, and the limit of detection is as low as 1.2 mu M. In addition, the inhibitory effects of caffeic acid and caffein on the formation of fibrillar IAPP were evaluated. The method is simple and effective, and therefore is perceived to represent a promising scheme for determination of fibrillar IAPPs and their inhibitors.