DNA-templated copper nanoparticles: Versatile platform for label-free bioassays

Label strategies are the mainstream techniques and gain great success for the sensitive quantification of biomolecules. However, they sometimes suffer from the inconveniences of time-consuming labeling, low stability of bioconjugates, and the function disorder of labeled-biomolecules. Recently, DNA-templated Cu nanoparticles (NPs) exhibit great potential for label-free fluorescent bioassays, thanks to the advantages of outstanding fluorescent properties, low toxicity, low price, good biocompatibility, and more importantly, instantaneous reaction, and facile integration with nucleic acid-based signal amplification and target-recognition strategies. In this review, we aim to discuss major developments and applications of DNA-CuNPs-based label-free assays for biomolecules. The DNA structures were manipulated for amplified sensing, multimode sensing, and versatile applications including cancer cell analysis, polyacrylamide gel electrophoresis, logic circuit, genotyping etc. Emerging analytical strategies were also discussed in detail. We address the advantages, applicable situations, and limitations of DNA-CuNPs-based label-free strategies and propose suggestions for future developments.