Optical Nanobiosensor for Monitoring an Apoptotic Signaling Process in a Single Living Cell Following Photodynamic Therapy

Abstract:

Optical nanobiosensors have enabled bioanalytical measurements to be undertaken within volumes as small as that of single biological cells. In this work, we use nanobiosensors to monitor a molecular signaling process, i.e., caspase-7 activation, following photodynamic therapy (PDT) induced apoptosis in breast cancer cells (MCF-7). PDT induces the mitochondrial pathway of apoptosis which triggers cytochrome c release, activation of caspases-9, -8 and -7 and cleavage of poly (ADP-ribose) polymerase (Parp) protein. Caspase-7 is an important apoptosis-related cysteine protease involved in the activation cascade of caspases and in the proteolytic cleavage of Parp protein. Caspase-7 was detected and identified intracellularly using optical nanobiosensors. Our results show the detection of caspase-7 in single living MCF-cells which in essence typifies the apoptotic event induced by a PDT drug. This work, in principle, demonstrates the minimally invasive capability of optical nanobiosensors to measure important signaling molecules and events in pathways at the single cell level.

Keywords: OPTICAL NANOBIOSENSOR; SINGLE CELL ANALYSIS; APOPTOSIS

Document Type: Research article

DOI: 10.1166/jnn.2005.426