Design Strategies of Gold Nanoparticles‐Based Biosensors Coupled with Hybridization Chain Reaction or Catalytic Hairpin Assembly

Abstract Gold nanoparticles (AuNPs) have been a popular choice of biosensing material for decades. Given their remarkable physicochemical properties, they have been widely employed in different types of assays, including colorimetric, electrochemical, fluorescence and catalysis. With the emergence of enzyme‐free target amplification methods such as hybridization chain reaction (HCR) and catalytic hairpin assembly (CHA), integrating AuNPs with these DNA circuits provide a new paradigm in biosensing. This not only combines the advantages of each component, it also addresses limitations of certain design principles and allows improvement of the assay performance. This review aims to provide a comprehensive reference on different ways to construct AuNPs‐based biosensors assisted by HCR and CHA based on different detection principles. For each type of assay, the common design principle is presented and specific features are highlighted that may shed new light on the translation of AuNPs‐HCR or AuNPs‐CHA biosensors to biologically relevant applications.