Easily Fabricated Microfluidic Devices Using Permanent Marker Inks for Enzyme Assays.

Coreen Gallibu,Chrisha Gallibu,Frank Gomez,Ani Avoundjian

doi:10.3390/mi7010006

Coreen Gallibu, Chrisha Gallibu + Show 2 more

Open Access

https://doi.org/10.3390/mi7010006

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Journal: Micromachines	Publication Date: Jan 12, 2016
Citations: 25	License type: CC BY 4.0

Affiliation: California State University Los Angeles

Abstract

In this communication, we describe microfluidic paper analytical devices (μPADs) easily fabricated from commercially available Sharpie ink permanent markers on chromatography paper to colorimetrically detect glucose using glucose oxidase (GOx). Here, solutions of horseradish peroxidase (HRP), GOx, and potassium iodide (KI)were directly spotted onto the center of the μPAD and flowed into samples of glucose that were separately spotted on the μPAD. Using an XY plotter (Roland DGA Corporation, Irvine, CA USA), several ink marks drawn in the paper act as the hydrophobic barriers, thereby, defining the hydrophilic fluid flow paths of the solutions. Two paper devices are described that act as independent assay zones. The glucose assay is based on the enzymatic oxidation of iodide to iodine whereby a color change from clear to brownish-yellow is associated with the presence of glucose. In these experiments, two designs are highlighted that consist of circular paper test regions fabricated for colorimetric and subsequent quantification detection of glucose. The use of permanent markers for paper patterning is inexpensive and rapid and does not require special laboratory equipment or technical skill.

Highlights

Microfluidics is an exciting technology that has shown considerable promise for producing practical devices, in particular for the analysis of proteins of medical significance
To demonstrate the efficacy of the Sharpie permanent marker μPADs, we examined the enzymatic oxidation of iodide to iodine
Glucose is oxidized by glucose oxidase (GOx) forming hydrogen peroxide that is subsequently reduced to water by Horseradish peroxidase (HRP) concomitant with the oxidation of iodide to iodine

Summary

Introduction

Microfluidics is an exciting technology that has shown considerable promise for producing practical devices, in particular for the analysis of proteins of medical significance. While there have been a number of reports detailing versatile and successfully applied in a number of applications including screening of antibiotics and inexpensive fabrication methods for POC devices, there is an ever-increasing need in resource-limited pharmaceuticals [33], DNA detection [34], chemical screening in multilayer 3D cell cultures [35], areas for accessing quality diagnostic testing [27,28,29,30,31,32]. We describe the design and development of μPADs fabricated from Sharpie ink permanent oxidase GOx. Using a low-cost XY plotter, several ink marks drawn in the paper act as the markers on chromatography paper to colorimetrically detect glucose using glucose oxidase GOx. Using hydrophobic barriers that define the hydrophilic fluid flow paths of the solutions. More expensive microfluidic-based patterning techniques for point-of-care (POC) diagnostic devices

Experimental Section

Device Fabrication

Results and Discussion

Conclusions