Fluorescence Activation Imaging of Cytochrome c Released from Mitochondria Using Aptameric Nanosensor

• Published in: Journal of the American Chemical Society Vol. 137; no. 2; pp. 982 - 989
• Main Authors: Chen, Ting-Ting, Tian, Xue, Liu, Chen-Liwei, Ge, Jia, Chu, Xia, Li, Yingfu
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 21.01.2015
• Subjects: Apoptosis; Aptamers, Nucleotide - chemistry; Aptamers, Nucleotide - metabolism; Biosensing Techniques - methods; Cell Survival; Cytochromes c - secretion; Graphite - chemistry; HeLa Cells; Humans; MCF-7 Cells; Mitochondria - secretion; Models, Molecular; Nanostructures - chemistry; Nanotechnology - instrumentation; Nucleic Acid Conformation; Optical Imaging; Oxides - chemistry; Protein Conformation
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja511988w

We have developed an aptameric nanosensor for fluorescence activation imaging of cytochrome c (Cyt c). Fluorescence imaging tools that enable visualization of key molecular players in apoptotic signaling are essential for cell biology and clinical theranostics. Cyt c is a major mediator in cell apoptosis. However, fluorescence imaging tools allowing direct visualization of Cyt c translocation in living cells have currently not been realized. We report for the first time the realization of a nanosensor tool that enables direct fluorescence activation imaging of Cyt c released from mitochondria in cell apoptosis. This strategy relies on spatially selective cytosolic delivery of a nanosensor constructed by assembly of a fluorophore-tagged DNA aptamer on PEGylated graphene nanosheets. The cytosolic release of Cyt c is able to dissociate the aptamer from graphene and trigger an activated fluorescence signal. The nanosensor is shown to exhibit high sensitivity and selectivity, rapid response, large signal-to-background ratio for in vitro, and intracellular detection of Cyt c. It also enables real-time visualization of the Cyt c release kinetics and direct identification of the regulators for apoptosis. The developed nanosensor may provide a very valuable tool for apoptotic studies and catalyze the fundamental interrogations of Cyt c-mediated biology.