Gold nanoparticles have been utilized in biomedical applications for over three centuries, with their unique electronic properties and historical applications in art and ancient medicine driving recent interest. These nanoparticles exhibit distinct physical properties compared to small molecules and bulk materials, making them versatile in medical diagnostics and therapeutics. This review discusses the design, synthesis, functionalization, and applications of gold nanoparticles in biomedicine, emphasizing their tailored interactions with biological systems to improve patient health. The authors argue that the era of gold nanotechnology-enabled biomedicine is upon us, with ongoing challenges in functionalizing nanoparticles for efficient binding, clearance, and biocompatibility, as well as assessing their long-term effects on human health and reproduction. The review covers various synthesis methods, including colloidal synthesis, template-based electrochemical deposition, and top-down fabrication techniques, and explores the functionalization of nanoparticles with biomolecules and imaging agents. It also highlights the potential of gold nanoparticles in surface-enhanced Raman scattering (SERS) for in vitro diagnostics and photothermal therapy.Gold nanoparticles have been utilized in biomedical applications for over three centuries, with their unique electronic properties and historical applications in art and ancient medicine driving recent interest. These nanoparticles exhibit distinct physical properties compared to small molecules and bulk materials, making them versatile in medical diagnostics and therapeutics. This review discusses the design, synthesis, functionalization, and applications of gold nanoparticles in biomedicine, emphasizing their tailored interactions with biological systems to improve patient health. The authors argue that the era of gold nanotechnology-enabled biomedicine is upon us, with ongoing challenges in functionalizing nanoparticles for efficient binding, clearance, and biocompatibility, as well as assessing their long-term effects on human health and reproduction. The review covers various synthesis methods, including colloidal synthesis, template-based electrochemical deposition, and top-down fabrication techniques, and explores the functionalization of nanoparticles with biomolecules and imaging agents. It also highlights the potential of gold nanoparticles in surface-enhanced Raman scattering (SERS) for in vitro diagnostics and photothermal therapy.