Fabrication of biocompatible plasmonic sensing platforms via direct growth of metal nanomaterials on modified silk films

Abstract

Combining silk with noble metal nanomaterials offers a promising route to create biocompatible plasmonic platforms for biological and chemical sensing. However, popular approaches including direct mixing and metal sputtering have inherent limitations such as aggregation and poor morphology control that hinder their practical applications. In this work, we report for the first time the direct growth of silver and gold nanostructures on silk films via a seed-mediated approach. The silk films were chemically modified using both pre- and post-treatment methods, and the resulting growth behaviors of silver and gold were investigated. Compared with gold, silver growth exhibited more reproducible and intriguing results. The effects of various growth parameters were examined in detail, and a growth mechanism was proposed. As a proof of concept, silk films coated with silver nanoplates were demonstrated as surface-enhanced Raman scattering (SERS) substrates capable of detecting pH changes using 4-mercaptobenzoic acid (4-MBA) as a probe molecule. This study not only demonstrates the fabrication of a biocompatible, SERS-active substrate but also provides valuable insight into the growth behavior of metal nanocrystals on biomaterial-based substrates.