title: In vivo monitoring of oxidative burst on aloe under salinity stress using hemoglobin and single-walled carbon nanotubes modified carbon fiber ultramicroelectrode.
abstract: Single-walled carbon nanotubes (SWCNTs) and hemoglobin (Hb) modified carbon fiber ultramicroelectrode (CFUME) were employed to construct a direct electron transfer based in vivo H2O2 sensor. At the low working potential of -0.1 V, Hb/SWCNTs/CFUME showed a dynamic range up to 0.405 mM with a low detection limit of 4 μM (S/N=3) and a high sensitivity of 1.07 log(A) log(M)(-1) cm(-2). The apparent Michaelis-Menten constant (Km, app) was estimated to be as low as 1.35 mM. Due to the extremely small dimension and low working potential, Hb/SWCNTs/CFUME could give directly amperometric in vivo monitoring of H2O2 in aloe leaves with salt stress for 19.5h without the requirement of complex data processing and extra surface coatings to avoid interferences. The sharp increase of H2O2 level in aloe leaves with salt stress was clearly observed using Hb/SWCNTs/CFUME from 12.5 h, while in the aloe without salt stress, H2O2 level remained stable in the whole measurement. For further confirming the in vivo response of Hb/SWCNTs/CFUME, catalase (CAT) was injected into the spot adjacent to the sensor and caused rapid current decrease, which suggests the scavenging of H2O2. These results indicate that Hb/SWCNTs/CFUME can be a powerful tool for in vivo investigation of ROS.
authors.affiliation: Britton Chance Center for Biomedical Photonics at Wuhan National Laboratory for Optoelectronics-Hubei Bioinformatics and Molecular Imaging Key Laboratory, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, P.R. China.
authors.forename: Qiong-Qiong
authors.initials: QQ
authors.lastname: Ren
authors.forename: Xiao-Jun
authors.initials: XJ
authors.lastname: Yuan
authors.forename: Xiao-Rong
authors.initials: XR
authors.lastname: Huang
authors.forename: Wei
authors.initials: W
authors.lastname: Wen
authors.forename: Yuan-Di
authors.initials: YD
authors.lastname: Zhao
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
mesh_terms: D000504:Aloe / Q000737:chemistry / Q000502:physiology*; D015374:Biosensing Techniques / Q000295:instrumentation*; D002244:Carbon / Q000737:chemistry*; D000077482:Carbon Fiber; D006454:Hemoglobins / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000032:analysis* / Q000378:metabolism; D008839:Microelectrodes; D037742:Nanotubes, Carbon / Q000737:chemistry*; D009997:Osmotic Pressure; D018515:Plant Leaves / Q000737:chemistry / Q000502:physiology; D054712:Salinity; D013312:Stress, Physiological
chemical_list: D000077482:Carbon Fiber; D006454:Hemoglobins; D037742:Nanotubes, Carbon; D002244:Carbon; D006861:Hydrogen Peroxide
keywords: Carbon fiber; Hemoglobin; Hydrogen peroxide; In vivo monitoring; Single-walled carbon nanotubes