A Gel-Based Separation-Free Point-of-Care Device for Whole Blood Glucose Detection

This article introduces a gel-based separation-free point-of-care (POC) device for whole blood glucose colorimetric detection. Enzymes and a chromogenic substrate needed for colorimetric detection of glucose were entrapped in a photopolymerized poly(ethylene) glycol diacrylate (PEG-DA) hydrogel that was cast-molded into a circular shape. Our method enables colorimetric detection without the need for preseparation of blood plasma as the nanometer-scale three-dimensional porous structure of the hydrogel allows the diffusion of small analytes such as glucose while blocking the much larger blood cells. Our method requires less enzymatic concentration and, hence, offers a cost-saving benefit. In addition, PEG-DA also acts as an enzyme stabilizer, and the shelf-life testing result shows that enzyme activity can be maintained in PEG-DA over a long period of time. The concept of this simple, cost-effective method was demonstrated by the colorimetric detection of blood glucose directly from human whole bloodthout any sample preparation steps. The results were compared with those of a spectrophotometry method and showed relative error ranging from 5 to 19%, and less than 9% when compared with a commercial glucose meter. The presented method has the potential to be broadly utilized for other whole blood biomolecule analyses in POC testing applications.