Group R14300 – Digital Microfluidics

1. Group R14300 – Digital Microfluidics Peter Dunning Paulina Klimkiewicz Matthew Partacz Andrew Greeley Thomas Wossner Wunna Kyaw

2. Problem Statement • Need for point of care medical testing devices where access to conventional tests is restricted • Ex: Doctor’s Offices, Remote Areas, Battlefields • A solution must be portable and cheap http://gdb.voanews.com/6C27D536-9955-4670-91C4-101E2D5A6322_w640_r1_s.jpg

3. Problem Statement • Lab-on-a-chip devices are capable of miniaturizing and automating biological protocols. • Devices suited for commercial use have just started to be developed. http://2.imimg.com/data2/GK/EX/MY-920622/micro-biological-testing-250x250.jpg http://www.lionixbv.nl/technology/technology-microfluidics.html

4. Digital Microfluidic Devices - Electro-wetting Cross-section view of Digital Microfluidic device. Dotted line indicates the shape of the meniscus before actuation. Modified from [2] • Array of electrodes which use the electrowetting effect to manipulate droplets. “Top view of flow on a ring structure” [3]

5. Voice of the Customer

6. Voice of the Customer

7. Functional Decomposition Much room for creativity Little to no room for creativity Medium amt. of room for creativity

8. Project Breakdown • Control System • Fluid Delivery System • Fabrication • Automation • User Interface • Packaging

9. Control System - Specs and Metrics Problem: Can an Arduino board be used to control a DMF device to the same or better accuracy as a NI PXI control system? What Do We Need? • Generate a sine wave • Amplify the wave to a large voltage (~90-110 Vrms) • Measure capacitance with a good resolution (~0.2pF) • Complete the protocol quickly (~30min) • Move/Merge droplets quickly (~100ms) • Split droplets quickly (~500ms) What Do We Know? • Benchmark: Dr. Schertzer completed these protocols at the University of Toronto using a National Instruments (NI) control system, a signal generator, and an amplifier

10. Control System - Potential Concepts Benchmark - Control System used in Schertzer et al • NI PXI System • Signal Generator • Voltage: 10Vp-p • Frequency: 10kHz • Controller • Matrix-Switching Device (4 inputs / 32 outputs) • Agilent 4288A Capacitance Meter • Resolution to ~0.20 pF • Custom Amplifier • Voltage: 90-110 Vrms

11. Signal Generator Board Control Board - Controls is a shield for the Arduino Microcontroller Switching Board Trek Model PZD700A High Voltage Amplifier Input Voltage: 0 to ±10 VDC Output Voltage: 0 to ±700 VDC - Droplet was found to completely cover an electrode in 200ms Arduino is open source firmware pin mapping board schematics KiCAD Hardware designs available for Board designs 320 independent channels and is highly modular Control System - Potential Concepts Arduino Dropbot System in Fobel et al - Generates a sine wave • Voltage: up to 20 Vp-p • Frequency: (0.1-50)kHz

12. Arduino is open source firmware pin mapping board schematics KiCAD Hardware designs available for Board designs 320 independent channels and is highly modular Control System - Potential Concepts Arduino Dropbot System in Fobel et al Arduino Mega 2560 Microcontroller - Controls Signal Generator Board, High Voltage Switching Board - Can estimate drop position, velocity - Software Available: • Arduino firmware • C++ Software • Microdrop Plugin

13. Control System - Feasibility Potential Staffing Needed • Mechanical Engineering • Electrical Engineering • Software Engineering • Computer Engineering • The Arduino Dropbot system used in Fobel et al paper was able to instantaneously measure droplet velocity, capacitance, and impedance in real time. • Arduino has: • Software: C++ software, Open source firmware • Hardware: Microcontroller with board schematics, and pin mapping • Dropbot has: • Software: Open source firmware, Microdrop Plugin • Hardware: KiCAD models to create the boards

14. Fluid Delivery System-HOQ

15. Fluid Delivery System-Specs and Metrics Problem: Is there a specific delivery system so that the desired volume of fluid can be extracted within the desired time? What We Need • Droplet to be extracted between .5s and 5s. • Droplet Volume must be within 3% error of desired volume. What We Know • Conventional Biological Protocols have been using pipettes and Syringes • Duke University have used Reservoirs in their DMF Devices.

16. Fluid Delivery System-Concepts • Syringe • .55 L ± .028 • Pipette • 1µL ± 4% • Reservoir • Volume from User Input • Plug-in Canister • Desired Volume can be extracted • Combination of These

17. Fluid Delivery System- Feasibility • Solutions • Reservoir system will allow us to easily dispense the fluids to the DMF device. • Using together with Pipettes will allow us to accurately dispense the desired droplet volume. • Plug-in Canister can be programmed to dispense the right amount while easily detachable and portable. • Staffing Required: • Students in the Mechanical Engineering discipline • Students in the Industrial Engineering discipline

18. Fabrication- HOQ [10]

19. Fabrication: Potential Concepts Common Techniques:Photolithography and wet or dry etching (clean room) Solutions outside the clean room: • PDMS stamp used to transfer a pattern onto a gold surface • Desktop laser printer pattern transfer: directly onto sheet of polyimide • Permanent marker electrode array outline Dielectric: Saran wrap Hydrophobic coating: Rain-X

20. Fabrication: Feasibility Microcontact printing (microCP) [7] • PDMS stamp used to deposit patterns of self assembled monolayers onto a substrate • device capable of full range of operations: dispensing, merging, motion and splitting Formed from circuit board substrates and gold compact disks using rapid marker masking [8] • procedure capable of producing devices with 50-60 μm spacing between actuating electrodes • saran wrap used a removable dielectric coating • rain-x: hydrophobic coating • able to move merge and split 1-12 μL droplets Desktop Laser Printer Pattern transfer [9] • Droplet motion: comparable to performance on chips made by photolithography • ultrarapid: 80 chips in 10 mins

21. Automation - HOQ

22. Automation - Specs and Metrics Problem: Can a protocol be automated using existing computing methods and hardware? What Do We Need? • Data Storage (~0.5GB) • Send Signal • Receive Signals • Processor (>10kHz, ~0.5GB) • Motion Planning What Do We Know? • Many algorithm based computing solutions already exist, just must be tailored for this specific application

23. Automation - Potential Concepts How to compute: • Existing computer • On-board processor • Open-source system Function: • Inputs: state of each electrode, protocol • Process: compute necessary move, merge, mix & split instructions for a specified protocol • Outputs: signals to activate control system switches, error signal to the user interface, result

24. Automation - Feasibility Each feature has many well known solutions. This project is determined to be feasible.

25. User Interface HOQ

26. User Interface - Potential Concepts LabVIEW Front Panel [4] -Computer program w/ visual display (i.e. LabVIEW VI) -Touchpad -Manual input (i.e. turn dials) -Remote communication (i.e. email) -LED indicators -Combination of these Example of “lab on a chip” [5] Handheld DMF device [6]

27. User Interface - Feasibility Technical Feasibility -Concepts for the user interface exist in many forms -Many existing DMF devices are able to accept instructions and output results via a user interface. -Example: RIT currently uses LabVIEW interface provided by National Instruments Staffing Requirements A few IE, ME, and EE students, possibly a CE as well

28. Packaging HOQ

29. Packaging-Concepts Minimizing Evaporation • Humidity sensing/control • Humidifier/hygrometer/controls • Temperature sensing/control • Refrigerator/thermometer/controls • Hybrid

30. Packaging-Feasibility Verify that size and weight constraints are met: Staff required: Several ME students, several EE students, possibly IE students

31. Questions/Areas of Uncertainty • How will environmental controls be implemented? • Chip form factor?

32. Next Steps • Confirm ER’s • Continue to refine HOQs • Examine resource and staffing requirements • Begin PRP development

33. References • [1] Mark, D., Haeberle, S., Roth, G., Von Stetten, F., and Zengerle, R., 2010, "Microfluidic Lab-on-a-Chip Platforms: Requirements, Characteristics and Applications," Chemical Society Reviews, 39(3), pp. 1153-1182. • [2] Cho, S. K., Moon, H. J., and Kim, C. J., 2003, "Creating, Transporting, Cutting, and Merging Liquid Droplets by Electrowetting-Based Actuation for Digital Microfluidic Circuits," Journal of Microelectromechanical Systems, 12(1), pp. 70-80. • [3] Fair, R., The Electrowetting Effect (in Air), February 1, http://microfluidics.ee.duke.edu/ • [4] http://www.mstarlabs.com/software/labview.html • [5] http://www.inc.com/magazine/201111/innovation-a-blood-test- on-a-chip.html • [6] http://doktori.bme.hu/bme_palyazat/2011/tudomanyos_muhely/ szenzorlabor_en.htm • [7] Watson, Michael W. L., Mohamed Abdelgawad, George Ye, Neal Yonson, Justin Trottier, and Aaron R. Wheeler. "Microcontact Printing-Based Fabrication of Digital Microfluidic Devices." Analytical Chemistry 78.22 (2006): 7877-885. Print. • [8] Abdelgawad, Mohamed, and Aaron R. Wheeler. "Low-cost, Rapid-prototyping of Digital Microfluidics Devices." Microfluidics and Nanofluidics 4.4 (2008): 349-55. Print. • [9] Abdelgawad, M., and A. R. Wheeler. "Rapid Prototyping in Copper Substrates for Digital Microfluidics." Advanced Materials 19.1 (2007): 133-37. Print. • [10] Schertzer, M. J., R. Ben-Mrad, and Pierre E. Sullivan. "Mechanical Filtration of Particles in Electrowetting on Dielectric Devices." Journal of Microelectromechanical Systems 20.4 (2011): 1010-015. Print.

34. End Questions?