title: An Amperometric Glucose Sensor Integrated into an Insulin Delivery Cannula: In Vitro and In Vivo Evaluation.
abstract: Labeling prohibits delivery of insulin at the site of subcutaneous continuous glucose monitoring (CGM). Integration of the sensing and insulin delivery functions into a single device would likely increase the usage of CGM in persons with type 1 diabetes.
  
  
  
  To understand the nature of such interference, we measured glucose at the site of bolus insulin delivery in swine using a flexible electrode strip that was laminated to the outer wall of an insulin delivery cannula. In terms of sensing design, we compared H2O2-measuring sensors biased at 600 mV with redox mediator-type sensors biased at 175 mV.
  
  
  
  In H2O2-measuring sensors, but not in sensors with redox-mediated chemistry, a spurious rise in current was seen after insulin lis-pro boluses. This prolonged artifact was accompanied by electrode poisoning. In redox-mediated sensors, the patterns of sensor signals acquired during delivery of saline and without any liquid delivery were similar to those acquired during insulin delivery.
  
  
  
  Considering in vitro and in vivo findings together, it became clear that the mechanism of interference is the oxidation, at high bias potentials, of phenolic preservatives present in insulin formulations. This effect can be avoided by the use of redox mediator chemistry using a low bias potential.
authors.affiliation: 1 Pacific Diabetes Technologies, Inc. , Portland, Oregon.
authors.forename: W Kenneth
authors.initials: WK
authors.lastname: Ward
authors.affiliation: 1 Pacific Diabetes Technologies, Inc. , Portland, Oregon.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Heinrich
authors.affiliation: 1 Pacific Diabetes Technologies, Inc. , Portland, Oregon.
authors.forename: Matthew
authors.initials: M
authors.lastname: Breen
authors.affiliation: 1 Pacific Diabetes Technologies, Inc. , Portland, Oregon.
authors.forename: Sheila
authors.initials: S
authors.lastname: Benware
authors.affiliation: 1 Pacific Diabetes Technologies, Inc. , Portland, Oregon.
authors.forename: Nicole
authors.initials: N
authors.lastname: Vollum
authors.affiliation: 1 Pacific Diabetes Technologies, Inc. , Portland, Oregon.
authors.forename: Kristin
authors.initials: K
authors.lastname: Morris
authors.affiliation: 1 Pacific Diabetes Technologies, Inc. , Portland, Oregon.
authors.forename: Chad
authors.initials: C
authors.lastname: Knutsen
authors.affiliation: 1 Pacific Diabetes Technologies, Inc. , Portland, Oregon.
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Kowalski
authors.affiliation: 1 Pacific Diabetes Technologies, Inc. , Portland, Oregon.
authors.forename: Scott
authors.initials: S
authors.lastname: Campbell
authors.affiliation: 1 Pacific Diabetes Technologies, Inc. , Portland, Oregon.
authors.forename: Jerry
authors.initials: J
authors.lastname: Biehler
authors.affiliation: 1 Pacific Diabetes Technologies, Inc. , Portland, Oregon.
authors.forename: Mark S
authors.initials: MS
authors.lastname: Vreeke
authors.affiliation: 1 Pacific Diabetes Technologies, Inc. , Portland, Oregon.
authors.forename: Scott M
authors.initials: SM
authors.lastname: Vanderwerf
authors.affiliation: 2 Division of Endocrinology, Diabetes and Nutrition, Oregon Health and Science University , Portland, Oregon.
authors.forename: Jessica R
authors.initials: JR
authors.lastname: Castle
authors.affiliation: 1 Pacific Diabetes Technologies, Inc. , Portland, Oregon.
authors.forename: Robert S
authors.initials: RS
authors.lastname: Cargill
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000032:analysis*; D015190:Blood Glucose Self-Monitoring / Q000295:instrumentation*; D005260:Female; D006801:Humans; D006861:Hydrogen Peroxide; D007004:Hypoglycemic Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D007328:Insulin / Q000008:administration & dosage / Q000627:therapeutic use*; D007332:Insulin Infusion Systems; D013552:Swine
chemical_list: D001786:Blood Glucose; D007004:Hypoglycemic Agents; D007328:Insulin; D006861:Hydrogen Peroxide
keywords: Continuous glucose monitoring; Continuous subcutaneous insulin infusion; Insulin delivery; Insulin delivery cannula.; Type 1 diabetes