Fabrication of a gel particle array in a microfluidic device for bioassays of protein and glucose in human urine samples

Abstract

This paper describes a simple method for fabricating a series of poly(ethylene glycol) diacrylate (PEG-DA) hydrogel microstructures inside microfluidic channels as probe for proteins and glucose. In order to demonstrate the feasibility of this newly developed system, bovine serum albumin (BSA) was chosen as a model protein. PEG microcolumns were used for the parallel detection of multiple components. Using tetrabromophenol blue (TBPB) and the horseradish peroxidase/ glucose oxidase reaction system, bovine serum albumin (BSA) and glucose in human urine were detected by color changes. The color changes for BSA within a concentration range of 1-150 lM, and glucose within a range of 50 mM-2 M could be directly distinguished by eyes or precisely identified by optical microscope. To show the practicability of the gel particle array, protein and glucose concentrations of real human urine samples were determined, resulting in a good correlation with hospital analysis. Notably, only a 5 mL sample was needed for a parallel measurement of both analytes. Conveniently, no special readout equipment or power source was required during the diagnosis process, which is promising for an application in rapid point-of-care diagnosis.

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

“…Immobilization of glucose sensing reagents in the gel material is important for ensuring the operational stability of glucose biosensor response . A number of papers have reported the immobilization of glucose-sensing reagents in gel to perform glucose sensing and applied such methods to various sensing mechanisms, including electrochemical, fluorescence, , surface plasmon resonance, , luminescence, , and colorimetry , methods. Colorimetry is one of the simplest forms of detection and thus commonly used in many glucose POC diagnosis methods.…”

Three-Dimensional Paper-Based Microfluidic Analysis Device for Simultaneous Detection of Multiple Biomarkers with a Smartphone

“…For colorimetric detection of albumin, the TBPB precipitated in the detection zone, which reacts like a pH indicator. The higher the amount of albumin, the more it reacts with TBPB, causing a color change from yellow to blue as the pH increases [ 32 ]. For colorimetric detection of cholesterol, the CO and CE precipitated in the detection zone, which oxidizes cholesterol to Chol-4-en-3-one while generating hydrogen peroxide.…”

Single-step design of hydrogel-based microfluidic assays for rapid diagnostics

“…Sensors for measurements of glucose, [3][4][5] phenol, 6 organophosphates 7 and urea 8 have been presented. Hydrogels are a suitable matrix to store reagents, 9,10 proteins, 6,7,11,12 DNA, 13 and cells [14][15][16][17][18][19] on microchips without loss of activity. In contrast to paper-based microfluidics, which has been investigated for mainly colorimetric ready-to-use diagnostic devices, 20,21 hydrogel chips offer more flexibility for complex samples such as cell suspensions and for sensitive optical detection methods.…”

“…Furthermore, in situ gel assays need an additional surface modification step to improve gel adhesion to the chip. [5][6][7][8][9][10]13,16,17 The elaborate preparations and need for external operation compromise the usability of such microfluidic diagnostic tools.…”