1. P15611: Digital Microfluidics Packaging
Design Review
P15611: Digital Microfluidics Packaging

2. Presentation Summary - 1
Background:
System Analysis:
Concept Development:
System Level Proposal:
Engineering Analysis:
Action Items:

3. Problem Statement - 2
The goal is to create an enclosure that can deliver fluid and provide a controlled environment for the DMF device.
Must allow easy camera and microscope access.
The enclosure must allow for electrical connections to the chip.
Should allow for environmental control and monitoring to maintain droplet size.
Must adhere to electrical safety and cleanliness standards.
Should allow for easy access to chip between tests.

4. Current Device - RIT - 3 Eventual goal: ELISA Assay
Will be used in the DMF Lab
Resistance Model between Plates
120 Channels
Lacks Environmental Controls
Open Chip Enclosure

5. Current Device - DropBot - 4
University of Toronto’s Wheeler Lab
320 Channels
Microdrop Graphical User Interface
Large Enclosure
Measures Position, Velocity, and Driving Force

6. Customer Requirements - 5

7. Engineering Requirements - 6

8. House of Quality - 7
Top 4: Environmental Control, Budget, Maximum Size, Test Setup Time
Size & Setup Time were more important than we expected.

9. Functional Decomposition -8

10. Morphological Chart - 9

11. Morphological Chart - 10

12. Selection Criteria-11 Cost Completion Time Set-Up Time
Ease of Chip Access
Size
Weight
Environmental Stability
Material Quality (Viewing)
Budgetary Efficiency
Ease of Use
Power
Precision/Accuracy

13. Concepts - 12 Concept I: Minimal Design Concept III: Alternate Design
Concept II: Dream Machine Concept IV: Selected Design

14. Pugh Charts - 13 Concepts III & IV are both are similar in scope
Concept I offers few features and does not make most efficient use of budget

15. Concept Sketch - 14

16. Concept Sketch - 15

17. Systems Architecture - 16

18. Systems Architecture - 17

19. Feasibility - Humidity/Temperature - 18
Relationship between humidity and temperature
Warm air holds more moisture than cool air
Approximate relationship:
20 degree F increase decreases humidity by 1/2
Temperature
40 degree F
60 degree F
80 degree F
Relative Humidity
100%
50%
25%

20. Feasibility - Humidity/Temperature - 19
Relative Humidity = Partial Pressure/Equilibrium Vapor Pressure
We are attempting to put the system to its equilibrium point
Vapor Pressure of water only interacts with water (Dalton’s Law)
Lowering temperature lowers equilibrium vapor pressure of all reagents

21. Feasibility - Temperature Monitoring- 20
Thermocouple costs range from a few dollars all the way up to 30 dollars per couple.
More expensive couples are electrically insulated.
The thermocouples leads can be as small as inches.
Standard couple calibrations allow for versatility.

22. Feasibility - Humidity Monitoring - 21
Digital measurement of the Humidity can done using either capacitive or resistive sensors.
The cost for the individual sensors range from a few dollars up to 100 dollars.
The actual size of a capacitive sensor is a 3x3 millimeter squared.

23. Feasibility - Viewing access - 22

24. Feasibility - Fluid Delivery - 23
Sandia National Laboratories:
Microfluidics hub with capillary tubes as fluid delivery medium.
An applied pressure source is used to form a droplet on the surface of the chip.
DMF actuation separates the droplet from the capillary tubing.
Kim, Hanyoup, Michael S. Bartsch, Ronald F. Renzi, Jim He, Jim Van De Vreugde, Mark R. Claudnic, and Kamlesh D. Patel. "AUTOMATED SAMPLE PREPARATION PLATFORM FOR NEXT GENERATION DNA SEQUENCING USING A DIGITAL MICROFLUIDIC HUB." (n.d.): n. pag. Sandia National Laboratories, United States of America. Web. <

25. Feasibility Peer Review - 24
Look into pressure controls
Consider material for enclosure
Preference towards plastic for insulation and electrical safety
Glass to prevent autofluorescence effects when using a microscope

26. Engineering Analysis Needed - 25
Virtual Model Analysis
Determine Compartment Volume
Position capillary tubing, sensors, etc
Ensure correct sizing of system components
Calculate temperature requirement for desired relative humidity.
Calculate pressure required to dispense the desired volume of fluid.

27. Test Plan - 26 Test Capillary Function Verify fluid delivery
Test Humidity and Temperature Sensors
Verify sensor accuracy
Test Microscope Compatibility
Verify fluorescence compatibility
Verify microscope can focus

28. Project Plan-Subsystems Design - 27

29. Projected Budget - 28

30. Risk Assessment - 29

31. Questions?

32. Extra Slide