Gold nanoparticles (GNPs) in biomedical and clinical applications: A review

Gold nanoparticles (GNPs) have been extensively used in various applications ranging from environmental detection to biomedical applications. Due to their unique characteristics such as tunable surface properties as well as surface plasmon resonance (SPR), GNPs have garnered attention in various applications exclusively in therapy and diagnostics. Their ease of synthesis and compatibility with various functionalizing ligands has made them efficient and a robust biomedical platform. Due to their flexibility in synthesis and functionalization, GNPs have been profoundly used in cancer treatment as well as, antiviral, and antibacterial agents. In addition, owing to possessing unique optical properties, GNPs have been utilized as molecular imaging and contrast agent. This article discusses and highlights special characteristics of GNPs that have been exploited in biomedical applications in recent years to improve biomedical research in various biomedical field such as nuclear medicine, molecular imaging and contrast agent, vaccine development, medical implant, diagnostics, biosensing, and lab-on-chip applications. Moreover, their size dependent biocompatibility, biodistribution, and excreation was discussed in details for various in vivo applications. At the forefront of modern theraputic technology, GNPs based cancer treatment and antiviral agents have great potential which is also highlighted briefly in this article. In addition, current state of ongoing clinical trials and challenges associated with regulatory approval are explored. Lastly, the article sheds light on recent findings on the toxicity of GNPs and discusses the current challenges and prospects to future direct GNPs based biomedical research.