Paper-Based Colorimetric Biosensor for Tear Glucose Measurements

Abstract

This paper describes a paper-based colorimetric biosensor for measuring glucose concentration levels in human tear samples. Colorimetric biosensors were wax printed on paper platforms and modified with chitosan previously prepared in acetic acid. The proposed device was explored to measure the glucose levels in human tear samples using 3,3′,5,5′-tetramethylbenzydine (TMB) as the chromogenic reagent. The paper-based colorimetric biosensor exhibited a linear behavior for the glucose concentration range between 0.1 and 1.0 mM. The achieved analytical sensitivity and limit of detection (LOD) were 84 AU/mM and 50 µM, respectively. Moreover, the device provided analytical reliability and no statistical difference when compared to the data recorded with a commercial glucometer. The proof-of-concept of our device was successfully demonstrated by measuring the glucose levels in six tear samples from nondiabetic subjects. In general, the results showed that the colorimetric biosensor has noticeable potential to be used as a powerful tool for tear glucose monitoring, since this fluid offers lower potential interferences, non-invasive sample collection and is pain-free. Furthermore, the proposed device could facilitate the treatment of diabetic patients who need constant control of glucose levels and cannot tolerate multiple finger sticks per day.

Disposable Sensors in Diagnostics, Food, and Environmental Monitoring

“…Especially, since the introduction of µPADs in 2007, a large number of µPADs for on‐site diagnostics have been reported . Paper‐based detection can be colorimetric and may require no instrumentation for operation (signal readout by the naked eye), which in turns reduces overall cost and complexity at the expense of sensitivity. The sensitivity, however, can be improved by the use of additional instruments, such as cameras (including smartphones), flatbed scanners (in the case of colorimetric detection) or potentiostats (for electrochemical µPADs) .…”

Microfluidics Based Point‐of‐Care Diagnostics

“…This four‐chambered multi‐analytes system had the ability to differentiate different concentration of glucose, lactate, chloride ions as well as pH of the sweat . Efforts have also been made to distinguish diabetic from non‐diabetic patients by investigating the glucose level in saliva, urine, and tear samples . Chitosan modified paper‐based MF colorimetric biosensor was fabricated that could efficiently detect glucose in tears (2 μL) .…”

“…Efforts have also been made to distinguish diabetic from non‐diabetic patients by investigating the glucose level in saliva, urine, and tear samples . Chitosan modified paper‐based MF colorimetric biosensor was fabricated that could efficiently detect glucose in tears (2 μL) . Ji et al fabricated MF integrated organic electrochemical transistors biosensor for multi‐analytes (glucose and lactate) detection in saliva biofluid .…”

A silver metal complex as a luminescent probe for enzymatic sensing of glucose in blood plasma and urine

“…As shown in Figure 4(a), the intensity of the characteristic peak at 530 nm and response curve increased when the concentration of glucose increased, and the response time (i.e., oxygen exhausting) was less than 10 s, which represents a fast response as compared with other optical glucose sensors (Table 2). 13,28,[34][35][36][37][38][39][40][41][42][43][44] Table 2), the proposed method provides a wider sensing range, faster response, and good sensitivity. Additionally, the Michaelis-Menten constant (K m ) of GOx in hydrogel was calculated by using a Lineweaver−Burke plot with glucose concentrations in the range of 3-35 mM.…”