Multifunctional gold nanoparticles: bridging detection, diagnosis, and targeted therapy in cancer.

Cancer remains a leading global health challenge, responsible for millions of deaths annually. Conventional therapies are hindered by systemic toxicity, drug resistance, and ineffective targeting of the tumor microenvironment (TME). Gold nanoparticles (AuNPs) have emerged as promising tools in oncology, offering unique plasmonic properties, high biocompatibility, and the ability to be engineered for multifunctional applications. Recent advancements include sustainable biogenic synthesis methods, precision targeting through ligands, aptamers, and peptides, and the development of theranostic platforms that integrate multimodal imaging with controlled drug and gene delivery. Additionally, AuNPs are being combined with therapies like photothermal-immunotherapy to remodel the TME, enhancing therapeutic efficacy. This review explores AuNP applications in cancer detection, diagnosis, and therapy, focusing on targeted drug/gene delivery to overcome chemoresistance, advanced biosensing tools for early detection, hybrid nanocarrier designs for TME penetration, and combinatorial platforms for integrating photodynamic, chemotherapy, and radiotherapy. It also addresses key translational barriers, such as protein corona dynamics, long-term biodistribution concerns, and the scalability of green synthesis methods. To facilitate clinical adoption, it emphasizes the need for GMP-compatible manufacturing, personalized nanomedicine through computational design, and standardized safety assessments. AuNPs represent a transformative approach to precision oncology, with the potential to integrate diagnostic and therapeutic functions into adaptable, real-time systems.