20210326 3Dcell labnotes

Pressure control of gel

Set up gel preparation for small amounts of agarose gel (~0.5 ml)
For other gels this can work with even smaller amounts of fluid
When gel is ready the pressure input (needle) and fluid output (tube) is glued to gas tighten with UV glue
Small ID tubing assures little waste of gel
Even 3 mbar is enough to flow gel through chip.
Changing which channel has higher pressure (by 2-3 mbar) reverses the flow of gelling fluid
Nice control and it will work when circuit is more hydrophobic!
Main problems:
- I had forgotten to sharpen tube (since hole was very small)
- Difficult to know how long it takes for fluid to reach chip. Fill tube before plugging in chip to have control of when it happens
- Accidental fluid into chip when I pressed tube in. Go to 0 pressure (and perhaps 3 mbar counterpressure) to avoid accidentaly filling
- Circuit was not sufficiently hydrophobic
- There should have been 2-3 posts at end of lamellae to make the difference in capillary pressure greater and avoid breaking through to the wrong side