Revision as of 12:02, 3 April 2022

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

• • Skolelisenser
  • Elev og lærerlisenser
• 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

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

Filling the chip

Water filling

Fibronectin filling

Cell filling

Running experiment