title: Nanomaterial-based electrochemical biosensors for cytochrome c using cytochrome c reductase.
abstract: Emerging evidences have pointed out that the release of cytochrome c (cyt c) from mitochondria into cytosol is a critical step in the activation of apoptosis. This article presents a novel approach for the detection of mitochondrial cyt c release for the first time using cytochrome c reductase (CcR) immobilized on nanoparticles decorated electrodes. Two kinds of nanomaterial-based biosensor platforms were used: (a) carbon nanotubes (CNT) incorporated polypyrrole (PPy) matrix on Pt electrode and (b) self-assembled monolayer (SAM) functionalized gold nanoparticles (GNP) in PPy-Pt. Scanning electron microscope was used to characterize the surface morphologies of the nanomaterial modified electrodes. Cyclic voltammograms of both the biosensors showed reversible redox peaks at -0.45 and -0.34 V vs Ag/AgCl, characteristic of CcR. In comparison, the CcR-CNT biosensor gave a detection limit of 0.5±0.03 μM cyt c, which was 4-fold better than the CcR-GNP biosensor (2±0.03 μM). Moreover, the CcR-CNT biosensor achieved a much larger linear range (1-1000 μM) over the CcR-GNP biosensor (5-600 μM) with 2-fold better sensitivity. The CcR-CNT-PPy-Pt biosensor was further applied to quantify the mitochondrial cyt c released in cytosol of A549 cells upon induction of apoptosis with doxorubicin, the results agreed well with standard western blot analysis.
authors.affiliation: Biomedical Research Laboratory, Department of Chemistry, VHNSN College, Virudhunagar-626001, Tamil Nadu, India.
authors.forename: Manickam
authors.initials: M
authors.lastname: Pandiaraj
authors.forename: Thangamuthu
authors.initials: T
authors.lastname: Madasamy
authors.forename: Paradesi Naidu
authors.initials: PN
authors.lastname: Gollavilli
authors.forename: Murugesan
authors.initials: M
authors.lastname: Balamurugan
authors.forename: Srigiridhar
authors.initials: S
authors.lastname: Kotamraju
authors.forename: Vepa Kameswara
authors.initials: VK
authors.lastname: Rao
authors.forename: Kalpana
authors.initials: K
authors.lastname: Bhargava
authors.forename: Chandran
authors.initials: C
authors.lastname: Karunakaran
mesh_terms: D000818:Animals; D015374:Biosensing Techniques / Q000379:methods*; D002417:Cattle; D045744:Cell Line, Tumor; D045304:Cytochromes c / Q000032:analysis* / Q000378:metabolism; D055664:Electrochemical Techniques; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry* / Q000378:metabolism; D006046:Gold; D006801:Humans; D057230:Limit of Detection; D009251:NADPH-Ferrihemoprotein Reductase / Q000737:chemistry* / Q000378:metabolism; D053758:Nanoparticles / Q000737:chemistry; D037742:Nanotubes, Carbon / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D011758:Pyrroles / Q000737:chemistry; D013552:Swine
chemical_list: D004800:Enzymes, Immobilized; D037742:Nanotubes, Carbon; D011108:Polymers; D011758:Pyrroles; C067635:polypyrrole; D006046:Gold; D045304:Cytochromes c; D009251:NADPH-Ferrihemoprotein Reductase