Recent developments and future perspectives for photoresponsive-based gold nanoparticles (Au-NPs) and their...

Photoresponsive gold nanoparticles (AuNPs) represent a dynamic class of nanomaterials combining the optical tunability of gold with the reversible photochemistry of organic chromophores. Functionalisation with azobenzene, fluorescein, perylene, and pyrene derivatives enables light-controlled modulation of molecular conformation, fluorescence, and surface interactions. These hybrid systems have shown wide applicability in drug delivery, imaging, biosensing, and photothermal therapy. This review summarises recent advances in their design, synthesis, and biomedical integration, with emphasis on photoisomerisation dynamics, optical coupling, and structure-function relationships. Key challenges including limited light penetration, photostability, and clinical scalability are highlighted alongside emerging prospects such as NIR-responsive and multi-stimuli platforms. Photoresponsive AuNPs thus offer a promising foundation for next-generation light-regulated biomaterials and precision nanomedicine.