title: Detection of cytochrome C in a single cell using an optical nanobiosensor.
abstract: In this work, the intracellular measurement of cytochrome c using an optical nanobiosensor is demonstrated. The nanobiosensor is a unique fiberoptics-based tool which allows the minimally invasive analysis of intracellular components. Cytochrome c is a very important protein to the process which produces cellular energy. In addition, cytochrome c is well-known as the protein involved in apoptosis, or programmed cell death. delta-Aminolevulinic acid (5-ALA) was used to induce apoptosis in MCF-7 human breast carcinoma cells. 5-ALA, a photodynamic therapy (PDT) drug in cells was activated by a HeNe laser beam. After the PDT photoactivation, the release of cytochrome c from the mitochondria to the cytoplasm in a MCF-7 cell was monitored by the optical nanobiosensor inserted inside the single cell and followed by an enzyme-linked immunosorbent assay (ELISA) outside the cell. The combination of the nanobiosensor with the ELISA immunoassay improved the detection sensitivity of the nanobiosensor due to enzymatic amplification. Our results lead to the investigation of an apoptotic pathway 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, Tennessee 37831-6101, USA.
authors.forename: Joon Myong
authors.initials: JM
authors.lastname: Song
authors.forename: Paul M
authors.initials: PM
authors.lastname: Kasili
authors.forename: Guy D
authors.initials: GD
authors.lastname: Griffin
authors.forename: Tuan
authors.initials: T
authors.lastname: Vo-Dinh
mesh_terms: D000622:Aminolevulinic Acid / Q000494:pharmacology / Q000528:radiation effects / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D015374:Biosensing Techniques / Q000379:methods*; D045744:Cell Line, Tumor; D045304:Cytochromes c / Q000032:analysis* / Q000187:drug effects / Q000378:metabolism; D004789:Enzyme Activation; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D036103:Nanotechnology / Q000379:methods; D055095:Optics and Photonics; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000494:pharmacology / Q000528:radiation effects / Q000627:therapeutic use; D012680:Sensitivity and Specificity
chemical_list: D017319:Photosensitizing Agents; D000622:Aminolevulinic Acid; D045304:Cytochromes c