Enzymatically amplified electrochemical detection for lipopolysaccharide using ferrocene-attached polymyxin B and its analogue.
Ferrocene-attached polymyxin B (PMB-Fc) was prepared by the reaction of polymyxin B with ferrocenoyl chloride in a toluene/pyridine mixture. An electrochemical detection of lipopolysaccharide (LPS) was carried out using a combination of PMB-Fc and an enzyme-modified electrode constructed from a glassy carbon electrode modified with a bovine serum albumin membrane containing glucose oxidase. The ferrocene units of the PMB-Fc molecules were oxidized on the electrode, and then reduced to the original neutral form by a glucose oxidase-catalyzed reaction in the presence of D-glucose. The consumption/regeneration cycle for PMB-Fc resulted in a chemically amplified current response. The current response for PMB-Fc decreased in association with its complexation with LPS, and the magnitude of this current decrease caused by LPS was also amplified by the recycling process. The enzyme-modified electrode exhibited a rapid response of 5 min for LPS with the detection limit as low as 50 ng ml(-1). Further, the addition of D-solbitol or poly(vinyl alcohol) of high concentration over 1 mg ml(-1) substantially induced no response, and three kinds of LPS from different strains exhibited similar magnitudes of current response for the same concentrations; these results suggest the advantages of this detection system for practical applications. Ferrocene-attached colistin, an analogue of PMB-Fc, was also effective for the LPS detection using the glucose oxidase-modified electrode.
National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan. s.iijima@aist.go.jp
Seiichiro
S
Iijima
Dai
D
Kato
Soichi
S
Yabuki
Osamu
O
Niwa
Fumio
F
Mizutani
D015374:Biosensing Techniques / Q000295:instrumentation*; D003217:Conductometry / Q000295:instrumentation*; D004566:Electrodes; D004789:Enzyme Activation; D004800:Enzymes, Immobilized; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005296:Ferrous Compounds / Q000737:chemistry*; D005949:Glucose Oxidase / Q000737:chemistry*; D008070:Lipopolysaccharides / Q000032:analysis*; D000075163:Metallocenes; D011112:Polymyxin B / Q000737:chemistry*; D011485:Protein Binding
D004800:Enzymes, Immobilized; D005296:Ferrous Compounds; D008070:Lipopolysaccharides; D000075163:Metallocenes; D005949:Glucose Oxidase; D011112:Polymyxin B; C004998:ferrocene