Love:Plasma cleaning

Organic extraction	 of PDMS			SOP #6 Craig Story 1/9/06

A certain amount of monomer/short polymer and catalyst may remain within the cured PDMS. The degree to which these molecules interfere with cell health has not yet been rigorously tested. The following steps can be taken to remove these molecules from PDMS prior to using the grids with cells. Be careful working with such large volumes of flammable liquids.

1. Place PDMS grids in a large excess volume (600-800 ml) of hexanes for 10-12 h. Stir with magnetic stir plate. A 1000 ml beaker with a “tripod” plastic tube holder and stir bar can be used, and may be found left in the hood in room 339. Keep covered with foil.

Note: Significant expansion of the grids will occur during the procedure, so leave room for expansion in the beaker.

2. Exchange hexanes, repeat the extraction for another 10-12 hours.

3. Replace hexanes with acetone, for 10-12 hours.

4. Exchange with fresh acetone for a final 10-12 hours.

5. Place grids in 100-150 degree oven 10 hours (overnight). The oven in the lab used for this is found below the bench near the sink in the chemistry room.