title: A Disposable Tear Glucose Biosensor-Part 4: Preliminary Animal Model Study Assessing Efficacy, Safety, and Feasibility.
abstract: OBJECTIVE
  A prototype tear glucose (TG) sensor was tested in New Zealand white rabbits to assess eye irritation, blood glucose (BG) and TG lag time, and correlation with BG.
  
  
  METHODS
  A total of 4 animals were used. Eye irritation was monitored by Lissamine green dye and analyzed using image analysis software. Lag time was correlated with an oral glucose load while recording TG and BG readings. Correlation between TG and BG were plotted against one another to form a correlation diagram, using a Yellow Springs Instrument (YSI) and self-monitoring of blood glucose as the reference measurements. Finally, TG levels were calculated using analytically derived expressions.
  
  
  RESULTS
  From repeated testing carried over the course of 12 months, little to no eye irritation was detected. TG fluctuations over time visually appeared to trace the same pattern as BG with an average lag times of 13 minutes. TG levels calculated from the device current measurements ranged from 4 to 20 mg/dL and correlated linearly with BG levels of 75-160 mg/dL (TG = 0.1723 BG = 7.9448 mg/dL; R2= .7544).
  
  
  CONCLUSIONS
  The first steps were taken toward preliminary development of a sensor for self-monitoring of tear glucose (SMTG). No conjunctival irritation in any of the animals was noted. Lag time between TG and BG was found to be noticeable, but a quantitative modeling to correlate lag time in this study is unnecessary. Measured currents from the sensors and the calculated TG showed promising correlation to BG levels. Previous analytical bench marking showed BG and TG levels consistent with other literature.
authors.affiliation: Biodesign Institute, Arizona State University, Tempe, AZ, USA Harrington Program of Biomedical Engineering, School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, USA jeffrey.labelle@asu.edu.
authors.forename: Jeffrey T
authors.initials: JT
authors.lastname: La Belle
authors.affiliation: Biodesign Institute, Arizona State University, Tempe, AZ, USA Harrington Program of Biomedical Engineering, School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, USA.
authors.forename: Erica
authors.initials: E
authors.lastname: Engelschall
authors.affiliation: Biodesign Institute, Arizona State University, Tempe, AZ, USA Harrington Program of Biomedical Engineering, School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, USA.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Lan
authors.affiliation: Biodesign Institute, Arizona State University, Tempe, AZ, USA Harrington Program of Biomedical Engineering, School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, USA.
authors.forename: Pankti
authors.initials: P
authors.lastname: Shah
authors.affiliation: Biodesign Institute, Arizona State University, Tempe, AZ, USA Harrington Program of Biomedical Engineering, School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, USA.
authors.forename: Neil
authors.initials: N
authors.lastname: Saez
authors.affiliation: Biodesign Institute, Arizona State University, Tempe, AZ, USA Harrington Program of Biomedical Engineering, School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, USA.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Maxwell
authors.affiliation: Biodesign Institute, Arizona State University, Tempe, AZ, USA Harrington Program of Biomedical Engineering, School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, USA.
authors.forename: Teagan
authors.initials: T
authors.lastname: Adamson
authors.affiliation: Biodesign Institute, Arizona State University, Tempe, AZ, USA Harrington Program of Biomedical Engineering, School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, USA.
authors.forename: Michelle
authors.initials: M
authors.lastname: Abou-Eid
authors.affiliation: Biodesign Institute, Arizona State University, Tempe, AZ, USA Harrington Program of Biomedical Engineering, School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, USA.
authors.forename: Kenyon
authors.initials: K
authors.lastname: McAferty
authors.affiliation: Department of Ophthalmology, Mayo Clinic, Scottsdale, AZ, USA.
authors.forename: Dharmendra R
authors.initials: DR
authors.lastname: Patel
authors.affiliation: Divisions of Endocrinology and of Preventive, Occupational, and Aerospace Medicine, Mayo Clinic, Scottsdale, AZ, USA.
authors.forename: Curtiss B
authors.initials: CB
authors.lastname: Cook
keywords: biosensor; diabetes mellitus; power analysis; sample size determination; tear glucose monitoring