title: Edge-plane microwire electrodes for highly sensitive H₂O₂ and glucose detection.
abstract: The promise of implantable electrochemical sensors is often undermined by the critical requirement of device miniaturization that inadvertently degrades sensor performance in terms of sensitivity and selectivity. Herein, we report a novel miniaturized and flexible amperometric sensor grown at the 'edge plane' of a 25-μm gold wire. Such geometry affords extreme miniaturization along with ease of fabrication, minimal iR drop and 3-D diffusion for effective mass transfer. This together with electrochemical rebuilding of the Au working electrode and subsequent Pt nanoparticles deposition resulted in the highest H2O2 sensitivity (33 mA mM(-1) cm(-2)), reported thus far. Concurrent electrodeposition of o-phenylenediamine with glucose oxidase afforded glucose detection at these edge-plane microsensors with a six fold improvement in sensitivity (1.2 mA mM(-1) cm(-2)) over previous reports. In addition, these sensors exhibit low operation potential (0.3 V), high selectivity (more than 95%) against in vivo interferences, and an apparent Michealis-Menten constant (K(m)(app)) of 17 and 75 mM of glucose in the absence and presence of an outer polyurethane coating, respectively. These features render the edge-plane sensor architecture as a powerful platform for next-generation implantable biosensors.
authors.affiliation: Nanomaterials Optoelectronics Laboratory, Polymer Program, Institute of Materials Science, University of Connecticut, Storrs, CT 06269, United States.
authors.forename: Liangliang
authors.initials: L
authors.lastname: Qiang
authors.affiliation: Nanomaterials Optoelectronics Laboratory, Polymer Program, Institute of Materials Science, University of Connecticut, Storrs, CT 06269, United States; Biorasis Inc., 23 Fellen Road, Storrs, CT 06268, United States.
authors.forename: Santhisagar
authors.initials: S
authors.lastname: Vaddiraju
authors.affiliation: Nanomaterials Optoelectronics Laboratory, Polymer Program, Institute of Materials Science, University of Connecticut, Storrs, CT 06269, United States.
authors.forename: Dipesh
authors.initials: D
authors.lastname: Patel
authors.affiliation: Nanomaterials Optoelectronics Laboratory, Polymer Program, Institute of Materials Science, University of Connecticut, Storrs, CT 06269, United States; Department of Chemistry, University of Connecticut, Storrs, CT 06269, United States.
authors.forename: Fotios
authors.initials: F
authors.lastname: Papadimitrakopoulos
mesh_terms: D015374:Biosensing Techniques; D055664:Electrochemical Techniques; D004800:Enzymes, Immobilized / Q000737:chemistry; D005947:Glucose / Q000737:chemistry / Q000302:isolation & purification*; D005949:Glucose Oxidase / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry / Q000302:isolation & purification*; D011140:Polyurethanes / Q000737:chemistry
chemical_list: D004800:Enzymes, Immobilized; D011140:Polyurethanes; D006046:Gold; D006861:Hydrogen Peroxide; D005949:Glucose Oxidase; D005947:Glucose