Kathryn Rose Verfaillie with Dr. Nivedita Gupta and Brian Zukas Microfluid Mass Transfer and Bringing Microfluidics to the High School Chemistry Lab Kathryn Rose Verfaillie with Dr. Nivedita Gupta and Brian Zukas Figure 2. Time to pH change at reaction completion vs overall flow rate Figure 1. Tube length to pH change at reaction completion vs overall flow rate Syringe 1 – 0.083 M HCl with Methyl Orange Syringe 2 – Pure 1-Octonol Syringe 3 – 0.1 M NaOH in 1-Octonol Chip made of PDMS with channels created using syringe tips submerged in PSMD while curing See images 3-7 for set up. Pumps run at different intervals of a rate ratio of 5:1. 75:15 μL up to 225:45 μL Increased in intervals of 0.5 The length to color change was recorded for each interval This length was converted to time Length and time versus flow rate were graphed to show the trend of mass transfer versus flow rates See Figures 1-2 Research Level Procedure To learn about and gain understanding of the uses of microfluidics To find ways to make the science more cost effective and accessible To test existing methods of high school accessible microfluidics and find ways of improving those methods Focus and Purpose High School Acid-base chemistry fundamentals Laminar flow Polymers The design process Microscale science Cutting edge modern science Professional mass transfer Precise control of fluids for research Manipulating chemicals and cells at new sizes Fluid physics Cell biology Drug discovery Life science and biotechnologies Professional vs High School Uses Syringe 1 Microfluidics2 “the science of manipulating and controlling fluids, in the range of micro- to picoliters” “Using a network of channels with dimensions from tens to hundreds of micrometers”2 Decreases sample and reagent use Shorter experiment time Reduces overall cost Improves precision Lowers limits of detection Run multiple analyses simultaneously Microfluidic Chip3 Set of micro-channels that are etched or molded into a material (often PDMS). Channels are connected and arranged to achieve features like mix, pump, sort, or control an environment Input and output pierced into the chip – interface What is Microfluidics / Microfluidic Chips Chip templates are printed on Skrinky Dink paper using a laser printer 150 °C vegetable oil is used to shrink the plastic The templates are adhered to a petri dish and covered in PDMS and baked overnight at 60 °C to cure the PDMS The chips are cut and removed from the template and inlet and outlet holes cut See images 8-12 Tubing is attached to the outlet holes and the samples are pulled form the inlet holes with a syringe Color change observed High School Level Procedure1 There were regular struggles in drawing the samples through the channels made with the Shrinky Dink templates The best results were with the designs that had the longest distance of combined tracks The trouble to draw through may have been due to a lack of depth of the channels Some solutions: Try printing the template multiple times to make a thicker template to cause deeper channels Possibly using a tape that isn’t woven so that it doesn’t settle into the channels and block them Changes and Improvements for Future Use/Study The method of using Shrinky dinks does in fact make the study of microfluidics more accessible and a bit cheaper However the process of degassing the PMDS requires a degassing oven which is expensive and not readily available in a high school classroom There are also some complications in the functionality of the chips that needs to be further explored Conclusion for High School Accessibility Shrunken Templates Procedure for both experiments Scientific uses of shrink dinks What can be studied with the cells I created What needs improvement Conclusion Discussion Syringe 2 Syringe 3 Original Template Microfluidic Chip Shrunken Template being flattened Syringe 2 Syringe 3 Syringe 2 Entrance Syringe 1 Entrance Templates in PDMS prepared to be cured in the oven Syringe 3 Entrance Syringe 2 Entrance Syringe 1 Entrance Chip Chips imprinted with channels and punched inlets and outlets and adhered to glass slides with tape Syringe 3 Entrance Syringe 3 Entrance HCl droplets Contained in 1-Octonol Chip with samples Outlet tube and syringe to draw samples through the chip Waste Sample Track where color change is measured Chip with samples drawn through Sources Hemling, Melissa, et al. “Microfluidics for High School Chemistry Students.”Journal of Chemical Education, no. 91, ser. 1, 9 Dec. 2013, pp. 112–115.ACS, pubs.acs.org/doi/abs/10.1021/ed4003018. “Microfluidic Definitions and Advantages.” Fluigent.com, www.fluigent.com/expertises/microfluidic-definitions-advantages/. “Microfluidics and Microfluidic Devices: Review.” ElveFlow.com, ElveFlow, www.elveflow.com/microfluidic-tutorials/microfluidic-reviews-and-tutorials/microfluidics-and-microfluidic-device-a-review/.