Framework nucleic acids as powerful mediator for metal nanomaterials in biosensing: A review

Metal nanomaterials are widely used in detection, diagnosis and medical imaging because of their high catalytic activity, easy preparation, excellent optical properties and high stability. However, their pseudo monodisperse nanostructures and spatially disordered distribution hinder their optical properties. In recent years, framework nucleic acids (FNAs) have been used as ligands (templates or molds) to mediate the synthesis of many metal nanomaterials, such as gold nanoparticles, silver nanoparticles, and gold‑palladium nanoparticles, for modulating and assembling the distribution of metal nanomaterials. Framework nucleic acids possess monodispersity, natural biocompatibility, addressability, spatial conformability and programmability. Thus, framework nucleic acids have vast potential to mediate the distribution of metal nanomaterials. Reviews on framework nucleic acid-mediated metal nanomaterials are rare. Therefore, this review aims to fill this gap by focusing on the design, synthesis, purification, and characterization of framework nucleic acids as mediating tools to facilitate readers' specific understanding of their properties, providing a comprehensive overview of framework nucleic acids to mediate the modulation and assembly of metal nanomaterials and their application in biosensors.