How to get the right number of crystals for data collection and soaking experiments: microseeding optimization

Microseeding is a very powerful method of accurately controlling the number of crystals in a drop. Often when microseeding is used for screening (random MMS microseeding) or optimization showers of small crystals form. To control the number of crystals you can set up dilutions of the seed stock. However, you can end up doing many rounds of seeding - how can you find the best dilution as quickly as possible?

Oryx robots have scripts to test dilutions of the seed stock systematically to find the best concentration:

The 'Cross Matrix' experiment can test up to 12 seed stocks against 8 precipitants.

The 'Additive Scatter' experiment can test up to 5 seed stocks against a 2D gradient, e.g. pH vs precipitant.

Case Study using the 'Cross Matrix' experiment: