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!
Physics and the search for fundamental laws: Is physics turning into biology?
3 hours ago in The Curious Wavefunction