ABSTRACT
This chapter discusses a few representative sensor designs based on the combination of energy transfer interaction with the use of luminescent quantum dots as donor, or acceptor, with metal nanoparticles, fluorescent dyes and proteins to measure the enzymatic activity in solution and in cell cultures. It also discusses the basic principles of energy transfer process, including fluorescence resonance energy transfer, bioluminescence resonance energy transfer, and chemiluminescence resonance energy transfer. The chapter outlines the specific features associated with these processes when applied to quantum dots (QDs) and gold nanoparticles (AuNPs). It provides a few representative examples where conjugates of QD–peptide, QD–protein, AuNP–peptide have been utilized to design specific sensing assemblies for targeting enzymatic activity in vitro or in vivo. The AuNPs act as strong fluorescence quenchers coupled to QD donors. The specificity of the nanosensor is provided by the use of a substrate peptide self-assembled on the AuNPs surface.
