Freeze Control of Nanoparticle Aggregation and Exploration as Surface Enhanced Raman Scattering (SERS) Platform

Abstract We propose freezing as an efficient method for controlling silver nanoparticle (AgNP) aggregation. Solutes are expelled from the ice crystals and concentrated in a freeze concentrated solution (FCS) upon freezing. AgNPs are also concentrated in the FCS and aggregate depending on their concentration therein. Because the FCS volume is a function of temperature as well as the cryoprotectant type and concentration, the aggregation of AgNPs can be controlled using these experimental parameters. The freeze‐induced AgNP aggregation allows simple preparations of efficient platforms for surface enhanced Raman scattering (SERS) measurements. The SERS sensitivity can be optimized by the AgNP concentration in the FCS.