A gold nanoparticle-based colorimetric strategy for DNA detection: principles and novel approaches

The development of nanotechnology has led to the rapid growth of many different fields, including sensors. Bulky and complex sensor systems are gradually being replaced by streamlined sensor devices with advantages in size, simplicity, cost-effectiveness, and fast response, allowing qualitative detection of target analyte on-site application for clinical diagnosis. Significantly, since the COVID-19 pandemic, research on developing test kits for detecting biological molecules has grown rapidly, with an increasing number of publications. The number of studies developing colorimetric sensors based on gold nanoparticles (AuNPs) has increased continuously over the years, demonstrating the potential application of this material. The surface plasmon resonance (SPR) effect and high biocompatibility of AuNPs make them different from many other metal nanomaterials. In addition, the peroxidase activity properties of AuNPs have also received much attention in colorimetric sensors. In this review, the colorimetric sensors developed based on the AuNP material platform for DNA detection will be discussed in detail. Among them, the commonly used synthesis methods of AuNPs based on their applications and the primary mechanism of AuNP-based colorimetric sensors for DNA detection will be discussed. In addition, AuNP-based colorimetric applications in POCT for pathogenic bacteria and viruses are also mentioned in this review to provide a broader perspective on the potential and developmental direction of AuNP-based colorimetric sensors. Another aspect this review provides is development strategies that allow simple readout using the naked eye, a spectrophotometer, or a smartphone camera, which present many opportunities for integration into other electronic devices.