A Wearable Cellulose Acetate-Coated Mouthguard Biosensor for In Vivo Salivary Glucose Measurement

Abstract

In this study, a cellulose acetate (CA) membrane is formed as an interference rejection membrane on a glucose sensor to measure glucose in saliva. Glucose in saliva is successfully measured in vivo without any pretreatment of human saliva. A mouthguard (MG) glucose sensor is developed to monitor salivary glucose, which is reported to be correlated with the blood glucose level. Salivary components of ascorbic acid (AA) and uric acid (UA) hinder the accurate measurement of the glucose concentration of human saliva. CA-coated electrodes are prepared to investigate the interference rejection membrane. To measure hydrogen peroxide, which is a reaction product of glucose oxidase, effects of AA and UA are examined. Characteristics of the fabricated biosensor are examined on the basis of artificial saliva. The as-developed MG sensor can quantify the glucose concentration in the range of 1.75–10 000 μmol/L, which includes a salivary sugar concentration of 20–200 μmol/L. For the measurement of saliva samples collected from healthy subjects, the output corresponding to the concentration is confirmed; this suggests the possibility of glucose measurement. This MG glucose sensor can provide a useful method for the unrestricted and noninvasive monitoring of saliva glucose for the management of diabetes patients.

Integrated Devices for Non‐Invasive Diagnostics

“…[ 62 ] Recently mouth guard applications for the measurement of saliva glucose via well‐established glucose oxidase reaction enabling sensitive detection in the clinically relevant range have been reported. [ 63,64 ] A very similar design has also been utilized for the diagnosis of degenerative cell changes such as Alzheimer's disease. [ 65 ] One recent study has followed an alternative path by deploying a different sensing approach, which relies on the colorimetric measurement using a disposable microfluidic paper‐based sensor.…”

“…Reproduced with permission. [ 64 ] Copyright 2020, American Chemical Society. C) Wearable “in‐mouth” platform for electrochemical sodium intake monitoring toward hypertension management.…”

Colorimetric Nanoplasmonics to Spot Hyperglycemia From Saliva

“…This requires the new salivary POCs to gain a breakthrough in terms of sensitivity, while maintaining rapidity, accuracy, and clear readout. A few examples in this context have been recently reported (Elkington et al, 2014), including pioneering works on wearable devices (de Castro et al, 2019;Arakawa et al, 2020), yet many opportunities in this field remain unexplored.…”

Micro/nanodevices for assessment and treatment in stomatology and ophthalmology

“…Takahiro et al designed a glucose sensor mouthguard to analyze saliva, with a layer of cellulose acetate film wrapped on the surface to eliminate the interference of ascorbic acid (AA) and uric acid (UA) in saliva (Fig. 3b) 54 . The working electrode and counting/reference electrode (RE) of the glucose sensor consisted of a 200-nm thick Pt electrode (1.6 mm 2 in size) and a 300-nm thick Ag/AgCl electrode (16 mm 2 in size).…”

“…a Fabrication of immune electrodes for saliva-based oral cancer detection8 . b A mouthguard sensor integrated with a wireless module and battery; the schematic (bottom) shows that the glucose sensor consists of an antiinterference membrane and an enzyme membrane on Pt and Ag/AgCl electrodes54 . c Organic electrochemical transistor (OECT) based on platinum nanoparticles modified with glucose oxidase and polyvinyl alcohol (PVA) for a highly sensitive, portable glucose biosensor56 .…”