General Competition (November 1993)

Structurally New Biopolymers Derived from Alpha-L-Amino Acids

Sponsor: Integra LifeSciences Corporation

• Project Performance Period: 1/1/1994 - 12/31/1996
• Total project (est.): $2,467,804.00
• Requested ATP funds: $1,998,879.00

ILC proposes a three-phase program to bring a new class of bioabsorbable polymers from the laboratory to the point where practical implant materials and orthopedic devices could be designed. The basic concept of polymerizing biological molecules -- rather like building artificial proteins -- to produce strong, plastic-like materials that would be gradually absorbed and replaced by the body as it heals is not new. Since the 1970s several such polymers based on amino acids have been studied, but all are insoluble, expensive, and difficult to process. Glyoxylic acid, glycolic acid and lactic acid all have been polymerized and developed into commercial surgical products -- bioabsorbable sutures, for example. These materials are not without drawbacks, however. A key issue in bioabsorbable materials is the toxicity of the degradation products of the polymer -- the acids produced by the breakdown of existing bioabsorbable polymers has been implicated in severe post-surgery inflammation in some cases. In addition, there are currently no effective bioabsorbable materials for cartilage, meniscal (knee joint) and tendon/ligament repair -- potentially a $500 million market. Research at Rutgers University has produced a new "pseudo-polyamino acid" based on a novel synthesis of tyrosine that avoids the material problems associated with amino acid polymers and shows great promise as a bioabsorbable material. It also is expected to avoid the problem of producing excessive acid as a breakdown product. Rutgers will continue the development of this class of polymers to improve their physical and chemical characteristics. Working with Rutgers and the Hospital for Joint Diseases, ILC will conduct in vitro tests to correlate the new polymer's physical properties to its chemical structure, study the interaction between candidate polymer formulations and living cells, including tissue compatibility, inflammatory response, bone growth and hard tissue response, and develop prototype devices including pins, screws, fibers, tubes and matrices suitable for advanced applications including cartilage, meniscal and tendon repair.

For project information:

Dr. George L. Brode, (609) 683-0900

ATP Project Manager

Mrunal Chapekar, (301) 975-6846
mrunal.chapekar@nist.gov