A self-driven microfluidic chip through a rapid surface modification of PDMS and its application for digital loop-mediated amplification (LAMP)

Digital loop-mediated amplification (LAMP) is an isothermal, quantitative DNA amplification approach which has high sensitivity and specificity and could be used to analyze extremely low amount of DNA within a short period of time. In this study, an integrated self-driven microfluidic chip was proposed herein for performing a digital LAMP process for vancomycin-resistant Enterococcus (VRE) diagnosis. The entire bacterial diagnosis could be automatically performed by capillary forces through the new polydimethylsiloxane (PDMS) surface treatment without using external pumps. Moreover, digitized droplets could be separated from each other by normally-close valves such that it could be quantitated. The contact angle of the treated PDMS surface was measured to be only 24°, which was the lowest value in literatures. This is the first time that a rapid (within 1 hour), simple, and hydrophilic PDMS surface modification method has been reported, which could be used in self-driven microfluidic devices for digital LAMP. This device may become a promising tool for clinical diagnosis and point-of-care applications.