Oppsummering

• LowT agarose seems to be a workable starting gel for cells in 3D
  • it's easy to prepare
  • it can be mixed with collagen to give cells adhesive contacts
• filling parts of microfluidic circuits with gel
  • 25 um thick SU8 worked fine with current patterns (30 um Ø posts)
  • 25 um thick circuits became sufficiently hydrophobic after 3-4 days to keep flow within posts
  • after 10-20 mm distance into circuit the flow resistance made the gel spill through the posts and into neighbouring areas
  • => Plans/ideas
    • shorter distances
    • thicker channels, but this requires better photolitho or wider posts
    • blocking fluid
      • dissolve out unreticulated PDMS with pentane/hexane before oxidising. This will keep the PDMS hydrophilic for weeks
      • fill neighbouring channels with perfluorodecalin (this is non-polar and will have a large contact angle with hydrophilic PDMS), see https://doi.org/10.1021/ac0346712
      • fill with agar solution
      • displace perfluorodecalin with cell media
• Photolitho troubles, check out Elveflow guides
  • Systematically test different illumination doses on small patterns
  • Clean isopropanol and PMGEA
  • Clean wafers properly in acetone (or piranha) before plasma cleaning. Try corona plasma inside LAF bench in 219 to avoid exposure to dust before hot plate