1. Lab-on-Chip Workshop March 25, 2016 Eric Johnston Soft Lithography Manager Quattrone Nanofabrication Facility

2. What is “Lab-on-a-Chip”?

3. We will cover:  Designing a mask (I can help with this)  Negative resist characteristics  Surface preparation  Spin coating  Exposing through mask  Post exposure bake  PDMS casting  Punch holes  PDMS Bonding  Filling

4. Design a Mask 1.Free software:  Layout Editor  DraftSight 2.Shapes to be closed polygons. 3.Polymask vendors (10um+): a)outputcity.com b)fineline-imaging.com c)photoplotstore.com 4.Chrome masks with Heidelberg

5. Layout Editor

6. DraftSight

7. Photoresists  SU8-2000 series photosensitive epoxy  SU8-3000 series  KMPR-1000 series  QNF supplies SU8-2050, KMPR 1050

8. Photoresists

9. Making a Master 200C100C

10. Photoresist Spin Coating, Baking

11. Photoresist Exposure ABM Mask Aligner: Calculate from data sheet Intensity is updated in SOP binder for each interface MA6 Mask Aligner: Simply enter dose required If using 360LP filter, must account for the attenuation

12. Photoresist Exposure

13. ABM Mask Aligner

14. Result: Delamination Exposure Problems: Short Exposure

15. Exposure Problems: Film Masks with Thin Features Chrome mask, 5um high features Film mask, 5um high features

16. Solution: 360nm long pass filter Exposure Problems: Long Exposure Result: T-Topping

17. Exposure Problems: Long Exposure

18. Post Exposure Bake (PEB)

19. PEB Problems: Thermal Stress Stress cracks due to sudden temperature changes

20. PEB Problems: High Aspect Ratio Features Delamination of high features with small footprints (related to thermal stress)

21. PDMS Casting degas

22. Polymeric Casting: The Miracle of PDMS o Inexpensive 2-Part silicone elastomer o Hydrophobic native state o Surface of PDMS can be rendered hydrophilic with oxygen plasma o Treatment last approximately 30 minutes o Allows bonding to glass or to PDMS o Allows functionalization of PDMS surface with hydrophilic molecules. o Gas permeable o Generally biocompatible, Food grade o Transparent in UV down to 240nm, ideal for fluorescence imaging www.cchem.berkeley.edu brandinside.d eu

23. Punch Holes (before bonding!)

24. Plasma Treatment for PDMS Bonding PDMS-Glass: 50sccm O 2, 30W, 30s PDMS-PDMS: 50sccm O 2, 30W, 60s

25. Tubing

26. Filling  Priming the device soon after plasma bonding (within 3 hours) yields better results.  Fully submerging the device inside a vacuum chamber for 20 minutes yielded the best results.

27. Soft Lithography Examples o Microfluidics o Stamping o Force Measurement

28. Soft Lithography Examples o Microfluidics o Stamping o Force Measurement

29. Soft Lithography Examples Particle Separation

30. Soft Lithography Examples Gradient Generator

31. Soft Lithography Examples Cell Culture Sugiura et al., Biotechnol. Bioeng. 100, 1156–1165 (2008)

32. Soft Lithography Examples o Microfluidics o Stamping o Force Measurement

33. Arrayed Stamping Example: Protein Deposition Chen et al (1997) Science, 276:1425 DOI: 10.1126/science.276.5317.1425 Kamat et al (2013) Small, 9:2272 DOI: 10.1002/smll.201202627 Forced Cell Morphology Vesicle Adhesion

34. Arrayed Stamping Method Schematic by Steven Henry

35. Soft Lithography Examples o Microfluidics o Stamping o Force Measurement

36. Force Measurement Example: PDMS cantilevered force transducers Tan et al (2002) PNAS, 100:1484 DOI: 10.1073pnas.0235407100

37. Preview of Hands-On Lab Work