Structurally Engineered Silica Shells on Gold Nanorods for Biomedical Applications

Owing to their unique optical and chemical properties, gold nanorods (AuNRs) are among the most frequently used nanomaterials for biomedical applications, including cancer therapy, imaging, and drug delivery. In particular, the longitudinal dipole plasmon wavelength of AuNRs can be verified from the visible to the near-infrared (NIR) region, allowing AuNRs to be used as photodynamic/photothermal and imaging contrast agents. At the same time, the silica shell is important as it enhances stability and facilitates the functionalization and biocompatibility of AuNRs, offering numerous advantages in biomedical applications. In this review, silica-coated AuNRs from a bioapplication perspective are focused. First, the importance of AuNRs for biomedical applications is explained and the purpose of silica coating on AuNRs is discussed. Then, recent studies on the development of silica-coated AuNRs from a biomedical perspective are reviewed. Subsequently, various strategies for engineering silica coatings and their properties in the biomedical field are reviewed. This review is expected to promote further research on next-generation silica-coated AuNRs for biomedical applications.