Gold nanoparticles in molecular diagnostics and molecular therapeutics

Gold nanoparticles, due to their unique physicochemical properties, are among the most widely used nanoscale-based platforms for molecular diagnostics. The intrinsic chemical stability and apparent lack of toxicity have also prompted for application in therapeutics, e.g., for imaging modalities and as vectorization strategies for molecular modulators, i.e., gene silencing, specific targeting of cellular pathways, etc. Because of their common molecular ground, these approaches have been synergistically coupled together into molecular theranostic systems that allow for radical new in vivo diagnostics modalities with simultaneous tackling of molecular disequilibria leading to disease. Despite this tremendous potential, gold nanoparticle- based systems still have to make their effective translation to the clinics. This chapter focuses on the use of gold nanoparticles for molecular diagnostics and molecular therapeutics and their application in theranostics. Attention is paid to those systems that have moved toward the clinics.