Gold nanoparticles in imaging: advances, applications, and future perspectives

Abstract

Plasmonic gold nanoparticles (AuNPs) have revolutionized bioimaging with their exceptional optical tunability, signal enhancement, and multimodal imaging capabilities. The localized surface plasmon resonance (LSPR) of AuNPs enables various high-sensitivity imaging techniques, including surface-enhanced Raman scattering (SERS), metal-enhanced fluorescence (MEF), photoluminescence (PL), photothermal (PT) imaging, and photoacoustic (PA) imaging. These modalities leverage AuNPs’ ability to amplify optical signals, convert light into heat precisely, and act as contrast agents for deep-tissue and molecular imaging. Recent advancements in NP engineering, such as chain-like assemblies, anisotropic structures, and hybrid nanocomposites, have dramatically enhanced photostability, signal intensity, and biocompatibility, addressing key limitations of conventional imaging probes. This review critically examines the latest advances in AuNP-based imaging, highlighting their impact on biomedical research and diagnostics. We explore cutting-edge strategies to optimize their structural and plasmonic properties, extend their functionality in multimodal platforms, and advance noninvasive, real-time imaging capabilities. Finally, we address the remaining challenges for clinical translation and provide insights into how AuNPs can redefine the future of medical imaging, precision diagnostics, and theragnostics.