The B. subtilis cells stuck nicely to coverslips spotted with various concentrations of poly-L-lysine. Unfortunately (but not unexpectedly) so did the polystyrene beads.
This morning I'll test whether briefly soaking the coverslip in a solution of the protein bovine serum albumin (BSA) will prevent the beads from sticking. BSA is widely used as a general 'blocking' agent - by sticking to surfaces it occupies all the sites that a valuable molecule or particle might otherwise stick to. And because it's just a protein with no significant biological activity, it shouldn't harm the cells or interfere with their interaction with DNA. We probably even have a BSA stock in the freezer.
If this works, then I can test whether some of the cells in the competent cell prep that are already stuck on the coverslip will bind to the beads. I hope to see that no cells bind to the streptavidin-coated beads, but that some cells do bind to beads that have been incubated with DNA and then washed.
And then I'm going snowshoeing on one of the local mountains!
6 hours ago in Variety of Life