Innovative strategies for enhancing AuNP-based point-of-care diagnostics: Focus on coronavirus detection

Highly pathogenic coronaviruses have consistently threatened humanity, encompassing SARS-CoV, MERS-CoV, SARS-CoV-2 and others. Swift detection and accurate diagnosis play a crucial role in promptly identifying high-risk populations, enabling timely intervention, and effectively breaking the transmission chain to reduce casualties. However, the diagnostic "gold standard" reverse transcription-polymerase chain reaction (RT-PCR) failed to meet the overwhelming demand during the pandemic due to insufficient equipment and trained personnel, impeding the effective control of viral spread. Undoubtedly, there is an urgent need for the development of convenient, rapid, and sensitive point-of-care (POC) diagnostic technology. Gold nanoparticles (AuNPs) satisfy the substantial market demand for biosensors owing to their exceptional optical properties and stability. In this comprehensive review, we summarize the potential advantages of AuNPs in visual solution colorimetry and lateral flow assays (LFAs) for the diagnosis of COVID-19. We delve into the techniques for enhancing LFA signals, with the goal of increasing both detection sensitivity and specificity. Furthermore, we include the application of smartphones for unbiased and objective interpretation of results. The examples presented in this review are anticipated to inspire researchers in designing AuNPs biosensors to address current and potential outbreaks of infectious diseases in the future.