“Naked-eye” recognition: Emerging gold nano-family for visual sensing

Abstract Gold nanomaterials (AuNMs)-based “naked-eye” sensing strategies are highly attractive due to their straightforward operations, valid mechanisms, and rapid processes. The strategies are mainly developed by exploiting the distinct properties of AuNMs, including localized surface plasmon resonance, and catalytic activity. The presence of target alters the inherent AuNMs’ properties, resulting with the sample color change that could be readily observed with naked eyes. Significantly, these visualization sensing platforms could be further expanded by incorporating technologies like enzyme reactions, metal ions-specific attachment, DNA hybridization, and even immunoassay. Herein, we describe the fundamental preparation strategies of AuNMs to yield their unique structures and tunable properties. Subsequently, AuNMs-based sensing strategies of which have shown sensitive and selective analytical sensing of different targets are discussed. We would further impart our insights and ideas following our analysis of current strategies in AuNMs-based visual sensing. This, we hope, would inspire more advanced nanomaterials-based visual sensors development.