Cellular Dynamics International has raised $40.6 million, according to a filing with the U.S. Securities and Exchange Commission. It had previously announced an $18 million round in late 2008. Click here to read a Milwaukee Journal-Sentinel story.

The company specializes in pluripotent stem cells, which can differentiate into any cell type for use in drug development. Dr. James Thomson of the UW-Madison is among its founders.

In December 2009, Cellular Dynamics launched its first product, iCell Cardiomyocytes, human heart cells designed to aid drug discovery and improve the predictability of drug compounds. The company takes cells from a patient’s own blood or other tissue and chemically reverses them back to a pluripotent state.

Researchers can use the cells to study a range of areas, including toxicity of new or existing drugs, to the electrodynamics of both healthy and diseased cardiac cells.