title: 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.
authors.affiliation: Advanced Biomedical Science and Technology Group, Life Sciences Division, Oak Ridge National Laboratory, PO. Box 2008, Oak Ridge, TN 37831-6101, USA.
authors.forename: Paul M
authors.initials: PM
authors.lastname: Kasili
authors.forename: Tuan
authors.initials: T
authors.lastname: Vo-Dinh
mesh_terms: D017209:Apoptosis; D015374:Biosensing Techniques; D045744:Cell Line, Tumor; D006801:Humans; D006868:Hydrolysis; D036103:Nanotechnology; D055095:Optics and Photonics; D010778:Photochemotherapy; D015398:Signal Transduction