Gold nanoparticles (AuNPs): A versatile material for biosensor application

Gold nanoparticles (AuNPs) have become the focus of rapid research due to their unique optical and electronic properties. There has been a noticeable increase in papers relating to AuNPs, with over 71,000 publications between 2019 and 2024. AuNPs possess exceptional stability, low resistance, high conductivity, and extensive light interaction, making them well-suited for biological sensing applications. This literature study begins by examining different approaches for synthesizing AuNPs, including chemical, physical, and biological methods, before exploring their use as biosensors. A comprehensive examination of the various detection methods, including localized surface plasmon resonance (LSPR), luminescence, surface-enhanced Raman scattering (SERS), surface plasmon resonance (SPR), and electrochemical properties, is facilitated through an exploration of the fundamental principles and classification of biosensors. We primarily focus on using AuNPs in medical diagnostics, highlighting current advancements in disease detection with AuNPs-based biosensors for conditions like COVID-19, dengue fever, and diabetes. The review emphasizes current research achievements in AuNPs synthesis and the bright prospects for their use in biocompatible and efficient biosensor applications.