Hayden Brady; Alex Jafek; Sean Harbertson; Raheel Samuel, University of Utah
Microfluidic chips have moved to the forefront of innovation and development in biological analytics, by reducing volume sizes, employing micro-scale physics, and incorporating many procedures into a single device. One application that is particularly well suited for microfluidics is polymerase chain reaction (PCR). PCR is the staple method used to amplify DNA, and essentially, relies on thermal cycling of a special chemical mixture. In this work, we present the optimization of hardware for performing PCR on microfluidic instruments at speeds as fast as 2 sec/cycle, which is up to 60 times faster than other applications and the fastest currently reported in the world. With the future goals of this project in mind, it became apparent that we needed to more thoroughly understand potential improvements for the fluid transport on the chip in order to increase control and replicability of results, which would then allow us to move on to more advanced testing. The design of our microfluidic chip required 8 significant iterations of channel design. The chips were judged on a performance scale in the categories of: ease of manufacture, failure rate, speed control, pressure drop, surface area, and thermal gradient. Failure rates decreased as we identified flaws in the manufacturing process and addressed new methods to avoid them. Significant changes included a new bonding and port gluing method, the introduction of rounded corners, a decreased surface area that influenced both chip adsorption and experienced pressure, and an improved method for imposing the thermal gradient across the chip. The future work of this project is very exciting: As all the aspects of this project are developed and brought together, the entire system will operate in a preconfigured manner that will eventually result in an accessible tool for while-you-wait DNA diagnostic tests.