Materials for protein delivery in tissue engineering.

The ability of protein agents to modulate cellular behaviors, such as motility, proliferation, adhesion and function, is the subject of intense research; new therapies involving proteins will likely result. Unfortunately, many proteins have short half-lives and the potential for toxicity after systemic delivery, so traditional routes of administration are not appropriate. Alternate methods for sustained delivery of these agents to the desired cells and tissues in biologically active conformations and concentrations are necessary. Techniques similar to those long used in the controlled delivery of drugs have been used to administer certain growth factors to cells and tissues; although clinical success has been limited to date, studies in animal models suggest the potential for tremendous advances in the near future. This review outlines the basic technology of controlled protein delivery using polymeric materials, and discusses some of the techniques under investigation for the efficient administration of proteins in tissue engineering.