title: Soft contact lens biosensor for in situ monitoring of tear glucose as non-invasive blood sugar assessment.
abstract: A contact lens (CL) biosensor for in situ monitoring of tear glucose was fabricated and tested. Biocompatible 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer and polydimethyl siloxane (PDMS) were employed as the biosensor material. The biosensor consists of a flexible Pt working electrode and a Ag/AgCl reference/counter electrode, which were formed by micro-electro-mechanical systems (MEMS) technique. The electrode at the sensing region was modified with glucose oxidase (GOD). The CL biosensor showed a good relationship between the output current and glucose concentration in a range of 0.03-5.0mM, with a correlation coefficient of 0.999. The calibration range covered the reported tear glucose concentrations in normal and diabetic patients. Also, the CL biosensor was applied to a rabbit for the purpose of tear glucose monitoring. The basal tear glucose was estimated to 0.11 mM. Also, the change of tear glucose induced by the change of blood sugar level was assessed by the oral glucose tolerance test. As a result, tear glucose level increased with a delay of 10 min from blood sugar level. The result showed that the CL biosensor is expected to provide further detailed information about the relationship between dynamics of blood glucose and tear glucose.
authors.affiliation: Department of Advanced Sciences and Technology for Biomedical Sensors, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
authors.forename: Ming Xing
authors.initials: MX
authors.lastname: Chu
authors.forename: Kumiko
authors.initials: K
authors.lastname: Miyajima
authors.forename: Daishi
authors.initials: D
authors.lastname: Takahashi
authors.forename: Takahiro
authors.initials: T
authors.lastname: Arakawa
authors.forename: Kenji
authors.initials: K
authors.lastname: Sano
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Sawada
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kudo
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Iwasaki
authors.forename: Kazunari
authors.initials: K
authors.lastname: Akiyoshi
authors.forename: Manabu
authors.initials: M
authors.lastname: Mochizuki
authors.forename: Kohji
authors.initials: K
authors.lastname: Mitsubayashi
mesh_terms: D000818:Animals; D015374:Biosensing Techniques / Q000379:methods*; D001786:Blood Glucose / Q000032:analysis*; D003263:Contact Lenses, Hydrophilic; D006801:Humans; D011817:Rabbits; D013666:Tears / Q000737:chemistry*
chemical_list: D001786:Blood Glucose