important considerations when preparing projectiles

 Basically when coating particles we need to pay careful attention to:

1. pH: This is most important!
2. Timing of incubation
3. Temperature of incubation
4. Salt concentration
5. Size of particles
6. Freshness of Spermidine (0.1M)
7. 2.5 M CaCl2 is filter sterilized and aliquots prepared ready to use.
8. Purity and concentration of DNA
9. Keeping particles suspended in the buffer solution while adding the spermidine and CaCL2
10. We have seen problems with particles sticking to the 1.5 Ml centrifuge tubes. DNA Lo-Bind tubes should work better.