Manufacturing fibrin

There is no perfect way to produce fibrin, a protein essential to blood clotting. Making a transgenic version of the compound raises concerns over the transfer of animal viruses to humans, while cell culture methods in which fibrin is isolated from human plasma give low levels of fibrin expression and carry the risk of transferring an infectious disease such as hepatitis.

Smith & Nephew plc has bought into transgenic fibrin production, last week picking PPL Therapeutics plc as a partner in developing products for orthopedics and wound repair. PTH (Roslin, U.K.) is expressing the components of fibrin in the milk of sheep...