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Revision as of 12:10, 3 April 2022 by Dagkd@uio.no (talk | contribs) (Filling the chip)

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Designing Microfluidic masks

  • Stanford microfluidics foundry has a good guide for designing your own device. That includes a guide to use AutoCAD.
  • AutoCAD (a program from Autodesk) is available free.
Some microfluidic circuit designs for a 3" wafer
  • You can use Klayout but we have more support for using Autocad.
  • Mask template for placing your designs
  • This guide for designing masks has some important tips
    • All fluid pathways have to be inside one or more closed contour(s)
    • The outer contour should be drawn in one layer (Give it a name like "Flow")
    • Any obstacles inside this outer contour must be drawn in another layer. Give it a name like "Flow inner polygons")
  • Displaying your design as PDF or otherwise is not straight forward because the resolution needed. You get a fair impression using CloudConvert which is much better than AutoCads own pdf export.
  • Example of a design where white lines (in screen shot below, black lines in PDF) are contours containing flow and green lines are inner polygons. Here is a PDF version of the file and the DWG file.
  • Rounding corners on a region
    • Command EXPLODE makes region into lines
    • Command JOIN joins lines into polylines
    • Command FILLET, downarrow to get options RADIUS and POLYLINE


Photolithography procedures

PDMS casting

  • PDMS preparation
  • Bring cup with PDMS close to wafer in Petri dish
  • Pour slowly and avoid introducing air bubbles
  • Remove air bubbles by puncturing them
  • Fill petri dish to 5-10 mm above wafer surface

Assembling the chip

  • Clean glass slide with IP and N2
  • Punch holes for fluid inlets
    • For 1/16" tubes use OD?? punch
    • For thin teflon tube use OD?? punch
  • Place both PDMS and glass slide with clean sides up on glass plate in plasma cleaner
  • Follow instructions for Plasma treatment
  • Place the PDMS on top of the glass slide and watch it attach
  • If necessary, apply a gentle pressure to the PDMS

Filling the chip

For sterilizing and filling the chip with water and fibronectin you need

  • 1ml syringe with
  • 20G needle and
  • 2cm long 1/16" teflon tube on the needle.
  • small beaker
  • ethanol
  • distilled water
  • Eppendorf tube of fibronectin
  • Cells in fresh media
  • Inlet and outlet tubes
    • Measure lengths of inlet and outlet tubes and cut
    • Sterilize the tubes


  • If you want a sterile chip move each object into LAF bench once they have been sterilized
  • Spray chip with ethanol and rub off glass side
  • Assemble syringe, needle and teflon tube
  • Spray ethanol and rub outside
  • Rinse beaker in ethanol and pour in a small amount of ethanol
  • Retract syringe half way in air, and fill teflon tube with ethanol
  • Empty syringe of ethanol and air, make sure it is dry
  • Empty beaker of ethanol

Water filling

  • Fill a small amount of distilled water in beaker
  • Retract <1ml distilled water into tube/needle/syringe
  • Fit in inlet of chip and fill slowly
  • Empty syringe and needle to be ready to use for fibronectin

Fibronectin filling

  • Take one Eppendorf with 0.5 ml fibronectin form freezer
  • Thaw the fibronectin
  • Retract fibronectin into tube/needle/syringe
  • fit in inlet of chip and fill slowly
  • Attach inlet and outlet tubes
  • Incubate for 30 min in incubator
  • Rinse with PBS
    • Details?
    • Pour ~?? ml PBS in sterile beaker
    • Fill sterile ?? ml syringe+needle with PBS
    • Slowly flow PBS through chip

Cell filling

Running experiment