Opportunities and Challenges of Silicon‐based Nanoparticles for Drug Delivery and Imaging

Silica nanoparticles are a type of colloidal amorphous metal oxide, which can be synthesized by a bottom‐up approach via the sol‐gel process. This chapter presents different architectures of silica nanoparticles (NPs), including nonporous silica NPs, mesoporous silica NPs, hollow silica NPs, and porous silica NPs, along with case studies of drug delivery and imaging from the literature. The chapter discusses the solid‐state characterization and medium‐dependent characterization of silica NPs. Trends in combinatorial chemistry and new approaches in drug design have resulted in more lipophilic potential drug compounds. The physical properties, surface modifications, and composition of porous and nonporous silicon‐based NPs can be tuned in order to make them powerful tools for imaging. Among all the molecular imaging modalities, optical imaging has been a versatile and easy‐to‐use approach in terms of available imaging agents to be used and relatively low cost of instrumentation.