Group R14300 Digital Microfluidics

Group R14300 Digital MicrofluidicsPeter DunningPaulina KlimkiewiczMatthew PartaczAndrew GreeleyThomas WossnerWunna Kyaw

Problem StatementNeed for point of care medical testing devices where access to conventional tests is restrictedEx: Doctors Offices, Remote Areas, Battlefields

A solution must be portable and cheap

http://gdb.voanews.com/6C27D536-9955-4670-91C4-101E2D5A6322_w640_r1_s.jpg

Problem StatementLab-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.jpghttp://www.lionixbv.nl/technology/technology-microfluidics.html

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]

Top view of flow on a ring structure [3]

Array of electrodes which use the electrowetting effect to manipulate droplets.

Voice of the Customer

Voice of the Customer

Functional Decomposition

Much room for creativityLittle to no room for creativityMedium amt. of room for creativityProject BreakdownControl SystemFluid Delivery System FabricationAutomationUser InterfacePackagingControl System - Specs and MetricsProblem: 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 waveAmplify 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 amplifierControl System - Potential Concepts

Benchmark - Control System used in Schertzer et al

NI PXI SystemSignal GeneratorVoltage: 10Vp-pFrequency: 10kHzControllerMatrix-Switching Device (4 inputs / 32 outputs)Agilent 4288A Capacitance MeterResolution to ~0.20 pFCustom AmplifierVoltage: 90-110 VrmsControl System - Potential Concepts

- Generates a sine wave Voltage: up to 20 Vp-pFrequency: (0.1-50)kHz

Signal Generator BoardControl Board

- Controls is a shield for the Arduino Microcontroller

Switching BoardArduino Dropbot System in Fobel et al

Trek Model PZD700A High Voltage AmplifierInput Voltage: 0 to 10 VDCOutput Voltage: 0 to 700 VDC- Droplet was found to completely cover an electrode in 200ms

Arduino is open sourcefirmwarepin mappingboard schematicsKiCAD Hardware designs available for Board designs320 independent channels and is highly modular

Control System - Potential Concepts

- Controls Signal Generator Board, High Voltage Switching Board - Can estimate drop position, velocity- Software Available:Arduino firmwareC++ SoftwareMicrodrop PluginArduino Mega 2560 Microcontroller

Arduino is open sourcefirmwarepin mappingboard schematicsKiCAD Hardware designs available for Board designs320 independent channels and is highly modular

Arduino Dropbot System in Fobel et al

Control System - Feasibility

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 firmwareHardware: Microcontroller with board schematics, and pin mappingDropbot has:Software: Open source firmware, Microdrop PluginHardware: KiCAD models to create the boardsPotential Staffing NeededMechanical EngineeringElectrical EngineeringSoftware EngineeringComputer EngineeringFluid Delivery System-HOQ

Fluid Delivery System-Specs and MetricsProblem: Is there a specific delivery system so that the desired volume of fluid can be extracted within the desired time?What We NeedDroplet to be extracted between .5s and 5s.Droplet Volume must be within 3% error of desired volume.What We KnowConventional Biological Protocols have been using pipettes and SyringesDuke University have used Reservoirs in their DMF Devices.Fluid Delivery System-ConceptsSyringe .55 L .028Pipette1L 4%ReservoirVolume from User InputPlug-in CanisterDesired Volume can be extractedCombination of These

Fluid Delivery System- FeasibilitySolutionsReservoir 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 disciplineStudents in the Industrial Engineering disciplineFabrication- HOQ

[10]Fabrication: Potential ConceptsCommon Techniques:Photolithography and wet or dry etching (clean room)Solutions outside the clean room:PDMS stamp used to transfer a pattern onto a gold surfaceDesktop laser printer pattern transfer: directly onto sheet of polyimidePermanent marker electrode array outlineDielectric: Saran wrapHydrophobic coating: Rain-X

Fabrication: Feasibility Microcontact printing (microCP) [7]PDMS stamp used to deposit patterns of self assembled monolayers onto a substratedevice 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 m spacing between actuating electrodessaran wrap used a removable dielectric coatingrain-x: hydrophobic coatingable to move merge and split 1-12 L droplets

Desktop Laser Printer Pattern transfer [9]Droplet motion: comparable to performance on chips made by photolithographyultrarapid: 80 chips in 10 mins

Automation - HOQ

Automation - Specs and MetricsProblem: 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 PlanningWhat Do We Know?Many algorithm based computing solutions already exist, just must be tailored for this specific applicationAutomation - Potential Concepts

How to compute:Existing computerOn-board processorOpen-source system

Function:Inputs: state of each electrode, protocolProcess: compute necessary move, merge, mix & split instructions for a specified protocolOutputs: signals to activate control system switches, error signal to the user interface, result

Automation - FeasibilityNeeded Features:Available Solutions:Data StorageMemory Card, HD, SSD, Peripheral networking, ROM cartridgeSend SignalsAnalog signals, digital signalsReceive SignalsMany ways to process signals..ProcessorMicro-processor, multi-core processorMotion PlanningGrid based algorithm, Sampling based algorithmEach feature has many well known solutions. This project is determined to be feasible.

User Interface HOQ

User Interface - Potential Concepts-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

LabVIEW Front Panel [4]Example of lab on a chip [5]Handheld DMF device [6]User Interface - FeasibilityTechnical 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 InstrumentsStaffing RequirementsA few IE, ME, and EE students, possibly a CE as well

Packaging HOQ

Packaging-ConceptsMinimizing EvaporationHumidity sensing/controlHumidifier/hygrometer/controlsTemperature sensing/controlRefrigerator/thermometer/controlsHybrid

Packaging-FeasibilityVerify that size and weight constraints are met:

Staff required: Several ME students, several EE students, possibly IE students

Questions/Areas of Uncertainty How will environmental controls be implemented?

Chip form factor?Next Steps Confirm ERsContinue to refine HOQsExamine resource and staffing requirementsBegin PRP development [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.

ReferencesEndQuestions?

Total Estimated Time: 16 min 20 secSet-up/handout Time: 1 minTime for Questions: 2 min 40 secTotal Time: 20 min