Low-cost and rapid prototyping of elecrochemical microfludic biosensors

Abstract

Electrochemical microfluidic biosensor is a widely used category of bioanalytical microdevices, with applications ranging from home-use glucometers to advanced blood analysis devices. They enable powerful microscale analyses in biology, physics and chemistry. Conventionally, the methods to fabricate these devices are either screen-printing, inkjet printing, or cleanroom-based photolithography. All these methods have slow iteration times, and cleanroom facilities are especially expensive and are limited in access to researchers in low-and-middle-income (LMIC) countries. In this thesis, a low-cost, accessible and rapid fabrication process of electrochemical microfluidic biosensors has been developed. This work leverages the accessibility of consumer-grade electronic craft cutters as the primary tool for patterning of sensor electrodes and microfluidic circuits, while commodity materials such as gold leaf, conductive silver ink, double-sided tape, vinyl sticker, plastic transparency films, and fabric adhesives are used as its base structural materials. The process enables fabrication of gold electrodes with dimensions as small as 450 µm and gaps of 110 µm, silver electrodes with dimensions as small as 600 µm, and fluid microchannels as small as 300 µm. Micro-volume hydrogen peroxide concentration measurements were performed as validation of biosensor performance, which achieved a limit of detection of 0.713 mM and sensitivity of 82.002 µA mM-1 cm-2 from 2 µL samples. The rapid process allows an iterative design-build-test cycle in less than 2 hours. This method is applicable in typical university laboratories and costs less than RM2100 to set up, enabling lower access barriers into the biosensor field for academic and industry researchers in low-resource settings.