title: Electrochemical endotoxin sensors based on TLR4/MD-2 complexes immobilized on gold electrodes.
abstract: Even low concentrations of endotoxins can be life-threatening. As such, continuous effort has been directed toward the development of sensitive and specific endotoxin detection systems. In this paper, we report the design and fabrication of a new electrochemical endotoxin sensor based on a human recombinant toll-like receptor 4 (rhTLR4) and myeloid differentiation-2 (MD-2) complex. The rhTLR4/MD-2 complex, which specifically binds to endotoxin, was immobilized on gold electrodes through a self-assembled monolayer (SAM) technique involving the use of dithiobis(succinimidyl undecanoate) (DSU). The surface topography of the electrodes at each fabrication stage was characterized with a nanosurface profiler and atomic force microscope (AFM). The electrochemical signals generated from interactions between the rhTLR4/MD-2 complex and the endotoxin were characterized by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). A linear relationship between the peak current and endotoxin concentration was obtained in the range of 0.0005 to 5 EU/mL with a correlation coefficient (R(2)) of 0.978. The estimated limit of detection (LOD) was fairly low, 0.0002 EU/mL. The rhTLR4/MD-2 based sensors exhibited no current responses to dipalmitoylphosphatidylcholine (DPPC) bearing two lipid chains, which is structurally similar to endotoxin, indicating the high specificity of the sensors to endotoxin.
authors.affiliation: Department of Chemical Engineering, Hanyang University, 1271 Sa-3 dong, Sangnok-gu, Ansan, Gyeonggi-do 426-791, Republic of Korea.
authors.forename: Tae Yun
authors.initials: TY
authors.lastname: Yeo
authors.forename: Ji Suk
authors.initials: JS
authors.lastname: Choi
authors.forename: Byung Kook
authors.initials: BK
authors.lastname: Lee
authors.forename: Beob Soo
authors.initials: BS
authors.lastname: Kim
authors.forename: Hwa In
authors.initials: HI
authors.lastname: Yoon
authors.forename: Hyeong Yun
authors.initials: HY
authors.lastname: Lee
authors.forename: Yong Woo
authors.initials: YW
authors.lastname: Cho
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D055664:Electrochemical Techniques / Q000379:methods*; D004566:Electrodes; D004731:Endotoxins / Q000032:analysis*; D006046:Gold / Q000737:chemistry; D051218:Lymphocyte Antigen 96 / Q000737:chemistry*; D012680:Sensitivity and Specificity; D051197:Toll-Like Receptor 4 / Q000737:chemistry*
chemical_list: D004731:Endotoxins; C495377:LY96 protein, human; D051218:Lymphocyte Antigen 96; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4; D006046:Gold