Aptamer Nanoflares for Molecular Detection in Living Cells*
This chapter demonstrates a composite nanomaterial, termed an aptamer nanoflare, that can directly quantify an intracellular analyte in a living cell. Aptamer nanoflares consist of a gold nanoparticle core functionalized with a dense monolayer of nucleic acid aptamers with a high affinity for adenosine triphosphate (ATP). The probes bind selectively to target molecules and release fluorescent reporters which indicate the presence of the analyte. Additionally, these nanoconjugates are readily taken up by cells where their signal intensity can be used to quantify intracellular analyte concentration. These nanoconjugates are a promising approach for the intracellular quantification of other small molecules or proteins, or as agents that use aptamer binding to elicit a biological response in living systems. Aptamer nanoflares readily enter cells where they can be used to directly quantify intracellular ATP levels, which makes them well suited for cell imaging and sorting studies.