Low Cost Microfluidic Device for Assaying Blood Glucose

Abstract

Herein, gravitational force based low cost colorimetric microfluidic device is developed for diagnostic purpose. Microfluidic system is developed by using discarded pen refills. Refill is filled with three layers of polymer. Bottom of the refill is filled with the polymer polyvinyl chloride (PVC). Second layer from the bottom i.e the layer above PVC layer is filled with silica gel immobilized with horse radish peroxidase (HRP), glucose oxidase (GOD) and o- dianisidine (dye). Whereas, third and the top most layer is filled with untreated silica gel. One drop of blood is poured at the inlet of microfluidic device. Without applying any external power, blood moves through the silica packed region by gravitational pull and capillary action of silica gel. Serum separation started within 30 seconds and subsequently within 2 min., serum successfully separates from blood by pure silica gel. The separated serum then comes in contact with the silica gel immobilized with enzymes and dye. The colour of the silica beads immobilized with enzymes and dye changes from white to orange when comes in contact with glucose in serum. Determination of the glucose in the blood is carried out on a desktop scanner. The developed microfluidic device do not require (i) pump or device to propel the fluid (ii) any type of special mesh or sieve to separate the serum from the blood. Microfluidic device developed is cheap and suitable for low cost setting areas.