![]() ![]() ![]() The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Ĭompeting interests: The authors of this manuscript have read the journal’s policy and have the following competing interests: The authors have filed a patent for the microfluidic platform device. George Korir acknowledges support from Howard Hughes Medical Institute International Student Predoctoral Fellowship, Stanford University’s Dean’s Doctoral Diversity Fellowship, Ric Weiland Fellowship and the His-Fong Ho Engineering Graduate Fellowship. Manu Prakash acknowledges support from Spectrum Foundation (NIH CTSA UL1 TR000093), Coulter Foundation, Pew Foundation, Society for Science and the Public (SPARK) and Moore Foundation. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are creditedĭata Availability: All relevant data are within the paper and its Supporting Information files.įunding: The project was funded by C-IDEA grant (National Institutes of Health grant RC4 TW008781-01). Received: SeptemAccepted: DecemPublished: March 4, 2015Ĭopyright: © 2015 Korir, Prakash. Eddington, University of Illinois at Chicago, UNITED STATES With its portable and robust design, low cost and ease-of-use, we envision punch card programmable microfluidics will bring complex control of microfluidic chips into field-based applications in low-resource settings and in the hands of children around the world.Ĭitation: Korir G, Prakash M (2015) Punch Card Programmable Microfluidics. Multiplexing is demonstrated by implementing an example colorimetric water quality assays for pH, ammonia, nitrite and nitrate content in different water samples. We demonstrate robustness of operation by encoding a string of characters representing the word “PUNCHCARD MICROFLUIDICS” using the droplet generator. Enabled by the complexity of codes that can be represented by a series of holes in punched paper tapes, we demonstrate independent control of 15 on-chip pumps with enhanced mixing, normally-closed valves and a novel on-demand impact-based droplet generator. A mechanical reader/actuator reads these paper tapes and correspondingly executes operations onto a microfluidic chip coupled to the platform in a plug-and-play fashion. A paper tape encodes information as a series of punched holes. Combining the idea of punch card programming with arbitrary fluid control, here we describe a self-contained, hand-crank powered, multiplex and robust programmable microfluidic platform. Incorporating multiple pumps, mixers and discrete valve based control of nanoliter fluids and droplets in an integrated, programmable manner without additional required external components has remained elusive. However multiple barriers exist towards low-cost field deployment of programmable microfluidics. ![]() The power regulation circuitry (U1) also has two protection diodes where the Schottky diode (D2) provides reverse power protection while the 1N4148 diode (D1) provides EMF spike protection for the regulator.Small volume fluid handling in single and multiphase microfluidics provides a promising strategy for efficient bio-chemical assays, low-cost point-of-care diagnostics and new approaches to scientific discoveries. The motor circuit is a BJT transistor with a protection diode to prevent EMF spikes in the motor from damaging the transistor. In this example, copper is being used for demonstration only. For a long-lasting device, the baseplate should be made from a corrosive material such as stainless steel. It is important that the paper clips are not under too much stress, otherwise, the paper clips will permanently deform and lose their flexibility. The card reader consists of 9 paper clips pushed into a conductive base plate. ![]() At this point, the microcontroller reads the byte from the card reader and then transmits that over UART. The motor stays on until a new clock signal is generated by the card reader. The microcontroller also has a UART receive line to receive the “read character” instruction which starts the motor when executed. This serial connection can be connected to either a computer or other microcontroller so that system can read the punched card. How Does the Punch Card Reader Work? The circuit uses a microcontroller to read parallel data from the card reader and then stream this data over a UART connection (via TX). ![]()
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