title: A biomimetic sensor for the determination of extracellular O(2)(-) using synthesized Mn-TPAA on TiO(2) nanoneedle film.
abstract: By immobilizing synthesized Mn-TPAA (TPAA=tris[2-[N-(2-pyridylmethyl) amino] ethyl] amine) on TiO(2) nanoneedle surface, a biosensor for superoxide ion (O(2)(-)) has been developed and applied for determination of O(2)(-) released from living cells. Direct electron transfer of Mn-TPAA is realized with a formal redox potential (E°') falling in the range of the E°' values of the redox couples O(2)/O(2)(-) and O(2)(-)/H(2)O(2). This suggests that Mn-TPAA on TiO(2) films is electrochemically active and capable of thermodynamically mediating both the oxidation of O(2)(-) to O(2) and the reduction of O(2)(-) to H(2)O(2). Therefore, Mn-TPAA immobilized on the TiO(2) films can be used electrochemically for determination of O(2)(-) due to its electrochemical activities and biomimetic catalytic activities like superoxide dismutase (SOD) toward O(2)(-). The present biomimetic O(2)(-) sensor shows high selectivity at the low working potential of 0V vs. Ag|AgCl, a wide linear range from 10(-7)M to 10(-4)M and a quick response time within 6s. By taking advantage of the developed method and the properties of biomimetic SOD themselves, we have realized the real-time monitoring of O(2)(-) concentration released from living cells and investigated the relationship between the concentration changes of O(2)(-) and intracelluar Ca(2+), which may gain additional insights on the reactive oxygen species (ROS) signal transduction and other physiological and pathological events.
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, Department of Chemistry, Tongji University, Siping Road 1239, Shanghai 200092, PR China.
authors.forename: Yongping
authors.initials: Y
authors.lastname: Luo
authors.forename: Guoqi
authors.initials: G
authors.lastname: Hu
authors.forename: Anwei
authors.initials: A
authors.lastname: Zhu
authors.forename: Biao
authors.initials: B
authors.lastname: Kong
authors.forename: Zhen
authors.initials: Z
authors.lastname: Wang
authors.forename: Chunyuan
authors.initials: C
authors.lastname: Liu
authors.forename: Yang
authors.initials: Y
authors.lastname: Tian
mesh_terms: D040761:Biomimetic Materials / Q000138:chemical synthesis / Q000737:chemistry; D015374:Biosensing Techniques / Q000379:methods*; D020013:Calcium Signaling; D055664:Electrochemical Techniques; D005029:Ethylenediamines; D005110:Extracellular Space / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008345:Manganese; D049329:Nanostructures / Q000737:chemistry; D010084:Oxidation-Reduction; D011725:Pyridines; D013482:Superoxide Dismutase; D013481:Superoxides / Q000032:analysis* / Q000378:metabolism; D014025:Titanium
chemical_list: D005029:Ethylenediamines; C507631:N,N',N''-tris(2-pyridylmethyl)tris(2-aminoethyl)amine; D011725:Pyridines; D013481:Superoxides; C009495:titanium dioxide; D008345:Manganese; D014025:Titanium; D013482:Superoxide Dismutase