A Python Module for Calculating Large-Scale Combinatorial Acoustic Liquid Handler Transfer Lists

The introduction of acoustic liquid handling into our laboratory in recent years has enabled a diversity of new screening modes. Combination screens have benefited most from our transition to acoustic liquid handling as the contactless transfers do not suffer from carryover effects or cross contamination that were an ever-present problem when using Pintool devices. We find that constructing transfer lists outside the instrument software is sometimes more efficient than manually creating combinatorial transfer protocols. If the number of compounds we plan to combine grows to more than a handful, even building the transfer lists without some type of script is cumbersome and error prone. We set out to build a Python module to assist with constructing combinatorial transfer lists for an arbitrary number of compounds and any number of components per combination. Here, we present a module that can be used to build a liquid handling transfer list for combinatorial assays. The module uses the source plate map to detect compounds, constructs all non-redundant permutations, calculates transfer volume to achieve the desired concentration, normalizes solvent volume, and outputs the transfer list as a CSV file. Though the module was conceived for combinatorial compound screens, we anticipate it could be useful for any combinatorial application that utilizes acoustic liquid handling.