Development of rapid and portable detection devices for point-of-care application is an important aspect of the modern diagnostic industry for effective diagnosis of many diseases. Current nucleic acid amplification-based (real time PCR) detection systems designed for portability are far from reality due to their complex protocol, difficulty of use and high costs limiting their widespread use among first responders, military and public health officials. The Chang lab envisions the development of a push-button, sample-to-answer, low-cost, self-powered and portable instrument with a slot where an integrated microfluidic chip can be inserted for detection of any target pathogen of interest [Fig. (A and B)].
We have developed a low-cost polymer based integrated chip capable of processing real sample to isolate and detect target nucleic acid in 30 min with two mismatch specificity and 10 fM sensitivity (Fig. C). The biosensor works on the principle that the flow of current through an anion-selective nanomembrane (functionalized with target specific probes) changes after hybridization of target nucleic acids (RNA or DNA). The hybridization changes the surface charge of the positively charged membrane and thereby affects the ion conductance across the membrane-solution interface due to depletion of ions near the surface (Fig. D). The sensing platform has been successfully tested against pathogens such as dengue virus, E.coli, Brucella, heterogeneous sample, and oral and pancreatic cancer.
Read more about ongoing Bioengineering projects in the Department of Chemical and Biomolecular Engineering by visiting http://cbe.nd.edu/faculty-research/bioengineering