Difference between revisions of "Microfluidics"

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(Designing Microfluidic masks)
(Assembling the chip =)
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* Fill petri dish to 5-10 mm above wafer surface
 
* Fill petri dish to 5-10 mm above wafer surface
  
= Assembling the chip ==
+
= Assembling the chip =
 
* Clean glass slide with IP and N2
 
* Clean glass slide with IP and N2
 
* Punch holes for fluid inlets
 
* Punch holes for fluid inlets
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* Place both PDMS and glass slide with clean sides up on glass plate in plasma cleaner  
 
* Place both PDMS and glass slide with clean sides up on glass plate in plasma cleaner  
 
* Follow instructions for [[Plasma treatment]]
 
* Follow instructions for [[Plasma treatment]]
 
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* 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 =
 
= Filling the chip =

Revision as of 11:03, 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
  • 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
  • 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

Water filling

Fibronectin filling

Cell filling

Running experiment