New aspects of biocompatibility testing: where should it be going?

In vitro tests that employ permanent cell lines represent a necessary, but primitive, first step in biocompatibility testing. Progress needs to be made in biofunctionality testing with respect to the final host, the human organism. This article looks at the principles and possibilities of in vitro test systems. Existing methods of cell and molecular biology are essential steps towards reducing animal experimentation. The potential of new in vivo models, such as genetically engineered animals, is also evaluated as a bridge between in vitro testing and the final application in the human body.