Making pharmaceutically relevant chemical libraries remains an important bottleneck in drug discovery. Two DNA-directed chemistry companies that were founded in the past two years are creating very different kinds of libraries that serve different purposes.

Both Ensemble Discovery Corp. and Vipergen ApS are using DNA-based chemistry to catalyze reactions and synthesize compounds, which allows for more complex molecules to be assembled in less time and with greater control than conventional chemistry methods allow.

Ensemble has created small, focused libraries of about 20,000 complex molecules, called macrocycles. Vipergen is betting that the fidelity of its technique will allow it to build bigger and bigger libraries - up to 1012 compounds - that will yield greater chemical diversity without sacrificing quality.