Facile Fabrication of Stable Enzyme-Based Colorimetric Glucose Biosensor on Cotton Using Polymer Entrapment

Abstract

Easy and rapid analyte detection can be democratised using fabric-based colorimetric sensor, which can be readily incorporated into everyday clothing or accessories, and digitally imaged by non-expert users using pervasive smartphones. However, fabricating colorimetric arrays, particularly enzyme-based sensors, on fabrics is nontrivial because enzyme activity cannot be guaranteed upon solid-state immobilisation on textiles, and because textiles present a highly-textured surface that could cause interference during digital imaging and reduce the limit of detection of known sensing formulations. Here, an enzyme-based multilayer sensor is fabricated on selected fabrics via physical adsorption and drop-casting, and utilised for proof-of-concept colorimetric detection of glucose on textiles. Substrates like cotton, cotton lycra, and filter paper are compared for colour uniformity and potential interference during digital imaging. Colour development on cotton achieved optimal homogeneity and reproducibility. The entrapment of enzymes with polyvinyl alcohol is demonstrated to enhance linear dynamic range, water fastness, and storage stability under different conditions. An image-processing algorithm is developed in OpenCV to automatically detect the colour spot and aid in quantitative analysis of glucose concentration. The present study suggests a facile strategy to fabricate a robust biosensor on textile that can achieve noninvasive monitoring of glucose in human biological fluid.