A flexible and wearable biosensor for tear glucose measurement

Abstract

A flexible and wearable amperometoric glucose sensor was fabricated and tested. Also, the sensor was utilized to tear glucose monitoring. The sensor was constructed by immobilizing GOD onto a flexible oxygen electrode (Pt working electrode and Ag/AgCl counter/reference electrode), which was fabricated using "Soft-MEMS" techniques onto a functional polymer membrane. In purpose of bioinstrumentation, adhesive agents were not used for constructing the flexible biosensor. Linear relationship between glucose concentration and output current was obtained in a range of 0.025-1.475 mmol/l, with a correlation coefficient of 0.998. Current dependences on pH and temperature were also evaluated. The current was largest at pH 7.0 and the current increased when temperature increased. This indicates that the output current depends on enzyme activity. Based on the basic characteristics investigation, the glucose sensor was applied to measurement of glucose in tear fluids on an eye site of a Japan white rabbit. The change of tear glucose level induced by oral-administration of glucose was monitored as a current change of the sensor attached on the eye site. In this investigation, the tear glucose level varied from 0.16 to 0.46 mmol/l. Although there was a delay of several tens of minutes towards blood sugar level, it is considered to be possible that non-invasive continuous glucose monitoring can be realized using the flexible biosensor.

Blood, sweat, and tears: developing clinically relevant protein biosensors for integrated body fluid analysis

“…119 There are several potential solutions which have been explored such as minimally invasive capillary collection at the corner of the eye 120 to calibration with a continuous monitoring device such as an electrode embedded contact lens. 121 Many groups have turned to contact lenses ( Fig. 2A) because a significant amount of research has already been carried out on the fabrication, biocompatibility and fouling mechanisms on these surfaces, 122 as discussed in a recent review.…”

Wearable Flexible Sensors: A Review

“…[110] would require the sensors to be subtle and sensitive. Another application of WFS is as glucose sensors via different mediums like tear [111], immobilization of glucose oxidase [112,113], etc. Electronic skins or e-skins [114,115] are another categories which was developed to mimic the functions like that of a natural skin and determine the changes in temperature, pressure or even your health conditions.…”

Wireless power transmission for medical applications

“…The feasibility studies and development of the integrated system brought forth with power allocation and distribution (PAD) concept in conjunction with power control circuits [8][9]. Recently, there have been many scientific researches for developing bio-sensors in medical applications [10][11][12] such as measurement of glucose level in human body or health-monitoring sensors. However, these researches have not addressed power requirements for microsensors in practical applications.…”