Evenly coating a substrate with PEG - (Sep/09/2013 )

Hi,

I am trying to use polyethylene glycol (PEG), MW 8000, to coat a tissue culture substrate to decrease cell adhesion.  The substrate is patterned similarly to the AggreWell plates from StemCell Technologies (which have little 800 um microwells or indentations that force cells to aggregate into spheres).

So my question is how to evenly coat the surfaces of these tiny microwells with a thin layer of PEG.  So far, I have tried allowing a 10% solution of PEG in dH2O to evaporate, but the deposited PEG appears to be extremely uneven (see attached photo).

Any help is appreciated!!

You could try spraying it on (e.g. similar to using a spray paint) rather than flooding with liquid.  Perhaps a surfactant would help too, but it may be hard to find one that won't also interfere with the cells.

Just wanted to update with another approach that was recommended to me: allow the solution to sit for 1 hour, then rinse off the excess.  There should be a thin layer deposited on the surface.

I see that many people use additional plasma treatment or other chemical means of adhering PEG to the substrate surface, so I'm a bit concerned about the deposited PEG re-dissolving in culture medium, but we'll see how it goes.