Gold nanoparticles as a versatile theranostic platform in oncology: A comprehensive point of view on synthesis, properties, functionalization, and clinical translation

Gold nanoparticles (AuNPs) are a key element of nanomedicine, providing flexible tools for cancer diagnosis and treatment. While their general properties and uses are well-known, this review offers a focused and updated overview of several less-explored areas. We pay special attention to the complex, dual role of AuNP-induced autophagy in cancer cell survival and the important effects of pharmacokinetic and immunological factors, such as size, shape, aspect ratio (AR), and surface roughness, on treatment effectiveness and safety. We analyze the biological outcomes of AuNPs made through chemical methods compared to "green" methods, showing how different synthesis approaches can lead to nanoparticles that promote apoptosis or necrosis. Additionally, this work reviews the clinical application of AuNP-based treatments, discussing important clinical trials and ongoing issues with biocompatibility, targeting efficiency, and regulatory approval. Finally, we look at new developments, including the use of AuNPs with advanced physical methods, such as TTFields, and the exciting potential of AuNPs in designing nanovaccines for personalized nanomedicine. By linking these important topics, this review seeks to connect basic research with the clinical application of AuNP-based cancer treatments. • Gold nanoparticles offer a versatile platform for cancer theranostics. • Tunable physicochemical properties dictate biological interactions and efficacy. • Critical comparison of chemical versus green synthesis routes is provided. • Advanced functionalization enables active targeting and combination therapies. • AuNPs show promise in phototherapy, radiotherapy, and bioimaging.