Engineering plasmonic Au nanostars: Enhanced plasmonic properties, preparation and biomedical application.

The anisotropic Au nanostars exhibit superior local electric field enhancement than their counterparts. Their longitudinal localized surface plasmon resonance (LSPR) wavelengths can be adjusted from visible to near infrared regions through morphological control. This review systematically synthesizes recent advances in star-shaped plasmonic nanoparticles, focusing on structure-property relationships and applications. A structured literature survey was conducted by screening peer-reviewed publications from databases period 2003-2025. The key insights include the defined classification frameworks of Au nanostars emphasizing three distinct nanostructures (fractal, hollow, and hybrid nanostructure), critical evaluation on the synthesis strategies and structural-property relationships of Au nanostars, applications in sensing and diagnostic, therapeutic application, and finally identification critical knowledge gaps and future research directions. These applications highlight the potential of Au nanostars in various biomedical and analytical fields. Despite significant progress, clinical translation remains challenging. The perspectives mainly include theoretical calculations, theoretical models, standardized preparation methods, and multi-stimuli responsive systems. We underscore the transformative potential of Au nanostars while highlighting the necessity for interdisciplinary collaboration to bridge existing gaps, provide some inspiration to develop novel functional nanomaterials with enhanced performance and ultimately accelerate their clinical translation.