title: Direct electrochemistry of hemoglobin on carbonized titania nanotubes and its application in a sensitive reagentless hydrogen peroxide biosensor.
abstract: Carbonized TiO(2) nanotubes (TNT/C) prepared by carbonization with organic polymers possess advantages combined from high conductivity of carbon and nanostructure of TiO(2) nanotubes. The material was used as a supporting matrix to immobilize a redox protein, hemoglobin (Hb), to explore its direct electron transfer ability. The apparent heterogeneous electron transfer rate constant (k(ET)) of Hb on TNT/C is 108s(-1), which is much higher than that in the reported works, demonstrating excellent direct electrochemistry behavior. The TNT/C-Hb modified glassy carbon electrode (GCE) demonstrates significant electrocatalytic activity for reduction of hydrogen peroxide with a small apparent Michaelis-Menten constant (87.5 microM). The TNT/C-Hb based H(2)O(2) sensor has a low detection limit (0.92 microM), fast response time (3s) and high dynamic response range (10(-6) to 10(-4)M), a much better performance than the reported works. These results demonstrate that a direct electrochemistry behavior can be significantly enhanced through simple carbon coating on a nanostructured material for higher reaction surface area and better conductivity. This work suggests that Hb-immobilized TNT/C has potential applications in a sensitive H(2)O(2) sensor.
authors: School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637457, Singapore.
authors: Chunxian
authors: C
authors: Guo
authors: Fengping
authors: F
authors: Hu
authors: Chang Ming
authors: CM
authors: Li
authors: Pei Kang
authors: PK
authors: Shen
mesh_terms: D001665:Binding Sites; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D004563:Electrochemistry / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006454:Hemoglobins / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000032:analysis*; D007202:Indicators and Reagents / Q000737:chemistry; D008839:Microelectrodes; D037742:Nanotubes, Carbon / Q000737:chemistry*; D011485:Protein Binding; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014025:Titanium / Q000737:chemistry*
chemical_list: D006454:Hemoglobins; D007202:Indicators and Reagents; D037742:Nanotubes, Carbon; C009495:titanium dioxide; D006861:Hydrogen Peroxide; D014025:Titanium