title: A self-powered amperometric lactate biosensor based on lactate oxidase immobilized in dimethylferrocene-modified LPEI.
abstract: Lactate is an important biomarker due to its excessive production by the body during anerobic metabolism. Existing methods for electrochemical lactate detection require the use of an external power source to supply a positive potential to the working electrode of a given device. Herein we describe a self-powered amperometric lactate biosensor that utilizes a dimethylferrocene-modified linear poly(ethylenimine) (FcMe2-LPEI) hydrogel to simultaneously immobilize and mediate electron transfer from lactate oxidase (LOx) at the anode and a previously described enzymatic cathode. Operating as a half-cell, the FcMe2-LPEI electrode material generates a jmax of 1.51 ± 0.13 mAcm(-2) with a KM of 1.6 ± 0.1 mM and a sensitivity of 400 ± 20 μAcm(-2)mM(-1) while operating with an applied potential of 0.3 V vs. SCE. When coupled with an enzymatic biocathode, the self-powered biosensor has a detection range between 0mM and 5mM lactate with a sensitivity of 45 ± 6 μAcm(-2)mM(-1). Additionally, the FcMe2-LPEI/LOx-based self-powered sensor is capable of generating a power density of 122 ± 5 μWcm(-2) with a current density of 657 ± 17 μAcm(-2) and an open circuit potential of 0.57 ± 0.01 V, which is sufficient to act as a supplemental power source for additional small electronic devices.
authors.affiliation: Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, UT 84112, United States.
authors.forename: David P
authors.initials: DP
authors.lastname: Hickey
authors.affiliation: Department of Mechanical Engineering, University of Utah, 315 South 1400 East, Salt Lake City, UT 84112, United States.
authors.forename: Russell C
authors.initials: RC
authors.lastname: Reid
authors.affiliation: Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, UT 84112, United States.
authors.forename: Ross D
authors.initials: RD
authors.lastname: Milton
authors.affiliation: Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, UT 84112, United States. Electronic address: minteer@chem.utah.edu.
authors.forename: Shelley D
authors.initials: SD
authors.lastname: Minteer
mesh_terms: D015374:Biosensing Techniques; D003217:Conductometry / Q000295:instrumentation*; D011211:Electric Power Supplies; D004800:Enzymes, Immobilized / Q000737:chemistry; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005296:Ferrous Compounds / Q000737:chemistry*; D019344:Lactic Acid / Q000032:analysis* / Q000737:chemistry; D000075163:Metallocenes; D006899:Mixed Function Oxygenases / Q000737:chemistry*; D011094:Polyethyleneimine / Q000737:chemistry
chemical_list: D004800:Enzymes, Immobilized; D005296:Ferrous Compounds; D000075163:Metallocenes; D019344:Lactic Acid; D011094:Polyethyleneimine; D006899:Mixed Function Oxygenases; C021497:lactate 2-monooxygenase; C004998:ferrocene
keywords: Biofuel cell; Biosensor; Lactate; Self-powered sensor