AuNP-based colorimetric and fluorometric sensors for detection of pathogenic bacteria: A review (2015–2025)

Pathogenic bacteria are responsible for a wide range of infectious diseases that pose serious threats to public health, food safety, and environmental hygiene. Rapid and accurate detection of these microorganisms is essential to prevent disease outbreaks and ensure effective monitoring. Conventional detection methods are often time-consuming, require specialized equipment, and demand skilled personnel, making them less suitable for on-site and real-time applications. To overcome these limitations, colorimetric and fluorometric sensors have emerged as effective alternatives due to their simplicity, high sensitivity, and potential for rapid visual or fluorescence-based signal generation. Among these, gold nanoparticles (AuNP)-based sensors have attracted significant attention because of their unique optical properties, ease of surface functionalization, and strong signal amplification capabilities. These sensors allow both colorimetric and fluorometric detection modes, offering dual-functionality for the recognition of pathogenic bacteria with enhanced precision. AuNPs exhibit localized surface plasmon resonance (LSPR), which facilitates color changes upon aggregation, and also enable fluorescence enhancement or quenching, making them suitable for a wide range of sensing platforms. This review aims to provide a comprehensive overview of the progress made from 2015 to 2025 in the development of AuNP-based colorimetric and fluorometric sensors for the detection of bacteria. The article highlights the recent advancements, design strategies, and practical applications of these sensing systems, emphasizing their role in improving sensitivity and enabling portable, cost-effective diagnostic tools for clinical, food safety, and environmental monitoring purposes. • Comprehensive analysis of AuNP-based colorimetric and fluorometric sensors for bacterial detection. • Overview of recent advancements in sensor design, fabrication, and functionalization strategies. • Exploration of applications in clinical diagnostics, food safety, and environmental monitoring.