Gold nanoparticle aggregate redispersion: a rising paradigm for colorimetric sensing

Conventional gold nanoparticle (AuNP)-based colorimetric sensing has long relied on the aggregation-induced “wine-red to grayish-blue” color change mode. However, issues such as nonspecific aggregation, irreversibility, and high background signals have severely compromised its selectivity and reliability. In recent years, a sensing strategy based on the redispersion of AuNP aggregates has emerged as a new paradigm, in which target-induced deaggregation triggers a solution color change from grayish-blue to wine-red, offering significant advantages including low background, high specificity, and reversibility. Nevertheless, the design principles, triggering mechanisms, and application frameworks of this strategy have yet to be systematically reviewed. On this basis, a unified framework for AuNP aggregate redispersion-based colorimetric sensing is attempted in this review. The two aggregation formation mechanisms, crosslinking and destabilization, are first elucidated, establishing the core logic that “ligands determine the response mode, while aggregate structure dictates the dispersion pathway.” subsequently, the molecular design of responsive ligands and the factors inducing deaggregation are highlighted, with a summary of design strategies and application advances in colorimetric sensing. Finally, current challenges and future directions are discussed, aiming to provide systematic guidance for the rational design of dispersion-type AuNP-based colorimetric sensors and to promote the translation of this field toward practical applications