Realizing the Potential of Commercial E-Textiles for Wearable Glucose Biosensing Application

Abstract

Advancements in wearable technology have enabled noninvasive health monitoring using biosensors. This research focuses on developing a textile-based sweat glucose sensor using commercially available conductive textiles, evading the complexity of traditional fabrication methods. A comparative analysis of three low-cost conductive textiles, Adafruit 1364, 1167, and 4762, has been conducted for electrochemical glucose detection with glucose-specific enzymes such as glucose oxidase (GOx) and glucose dehydrogenase (GDH). Adafruit 1364 outperformed others in morphological, electrochemical, and wearable properties. Cyclic voltammetry shows that Adafruit 1364 and 4762 effectively detect glucose at the potential of 0.23 and 0.08 V using glucose oxidase and 0.1 and 0.08 V using glucose dehydrogenase enzymes, respectively. Furthermore, chronoamperometry has been conducted to confirm the presence of glucose at 1 μM concentration. Differential pulse voltammetry was conducted to assess the sensitivity of the Adafruit 1364 fabric electrode using glucose solutions with concentrations of 0.05, 0.15, 0.25, and 0.5 mM. The electrode immobilized with GOx showed a sensitivity of 0.005 μA μM^-1 and a limit of detection (LOD) of 41.3 μM, while the electrode immobilized with GDH exhibited a sensitivity of 0.0019 μA μM^-1 and an LOD of 63.1 μM. The study also highlighted the reproducibility, effect of interferents, and advantageous wearable properties of these sensors.

Figure 1

Schematic illustration of (A) concept of e-textiles to be used as wearable glucose biosensors, where (i), (ii), and (iii) represent a microscopic view of Adafruit 1364, 1167, and 4762, respectively. (B) Electrode fabrication and glucose detection on the e-textile-integrated specific glucose enzymes. The authors have used an open-source platform (DALL-E) to generate the arm image used in Figure 1A.

Figure 2

(A) Scanning electron microscopy (SEM) of Adafruit 1364 (KNIT JERSEY Conductive Fabric); in situ image represents the component mapping of Adafruit 1364, where the blue region represents the presence of silver (Ag), red represents carbon (C), and yellow represents oxygen (O), (B) SEM of Adafruit 1167 (KNIT conductive fabric silver); in situ image represents the component mapping of Adafruit 1167, where the blue region represents the presence of silver (Ag), red represents carbon (C) and nitrogen (N), and yellow represents oxygen (O), and (C) SEM of Adafruit 4762 (NYLON fabric squares with conductive adhesive); in situ image represents the component mapping of Adafruit 4762, where the blue region represents the presence of nickel (Ni), red represents carbon (C) and nitrogen (N), yellow represents oxygen (O), and orange represents copper (Cu).

Figure 3

(A) Cyclic voltammetry; the in situ image represents cyclic voltammetry of Adafruit 4762. (B) Electrochemical impedance spectroscopy of Adafruit 1364, 1167, and 4762; the in situ image represents the equivalent circuit for circuit fitting.

Figure 4

(A) Optical water contact angle images of Adafruit 1364, 1167, and 4762. (B) Measured dynamic contact angle of water droplets on the surfaces for 800 s. (C) Drop in the optical contact angle with respect to time for each sample. (D) Sheet resistance of each sample before and after stretching; the in situ image represents sheet resistance before and after stretching for Adafruit 4762.

Figure 5

Chronoamperometry of all three samples (A) using glucose oxidase–Adafruit 1364: 0.23 V, Adafruit 1167: 0.22 V, and Adafruit 4762: 0.08 V and (B) using glucose dehydrogenase–Adafruit 1364: 0.1 V, Adafruit 1167: 0.16 V, and Adafruit 4762: 0.08 V. (C) Increase in current after addition of glucose; the in situ image represents chronoamperometry (A) using glucose oxidase and (B) using glucose dehydrogenase and (C) represents an increase in current for Adafruit 4762.

Figure 6

(A) Differential pulse voltammetry of GOx-immobilized Adafruit 1364 with 0, 0.05, 0.15, 0.25, and 0.5 mM glucose. (B) Calibration curve of GOx-immobilized Adafruit 1364 to calculate the sensitivity.

Figure 7

(A) Differential pulse voltammetry of GOx-immobilized Adafruit 1364 with 0.05 mM glucose at an interval of 4 and 8 h after storage at room temperature to check reproducibility. (B) Differential pulse voltammetry of GOx-immobilized Adafruit 1364 with 1 mM glucose (G), 1 mM lactic acid (LA), and 1 mM ascorbic Acid (AA) to study the interference effect.