If I need to use micromolar concentrations in my reaction, do I need to order the 1 μM scale?
Concentrations confuse a LOT of researchers. Micromolar is micromoles per liter. Depending on how much media you bathe your cells in the 1 μM scale may or may not be enough. For example, a 25mer phosphorothioate modified oligo should give you a minimum yield of 20 ODs after purification. This would translate into about 80 nmoles. 80 nmoles in 800 μL of media would be at a concentration of 100 μM. That same 80 nmoles in 8 mL would be at a concentration of 10 μM. If you can give us an idea of how much material you need, we can better advise you as to what scale to order.