When we read that the FDA has cleared a new absorbable suture, made from the material “isolated from bacteria modified by recombinant DNA technology,” we went ahead to check on the technology. The TephaFLEX Absorbable Suture, a product of Tepha Inc.’s genetic engineering process, is composed of designer biomaterials like no other.
The fundamental aspects of this technology is based upon new methods for producing a class of natural materials, called polyhydroxyalkanoates- or PHA polymers. These polymers are synthesized in nature by numerous microorganisms, and they have been recently recognized as the fifth class of naturally occurring biopolymers (along with the polyamino acids, polynucleic acids, polysaccharides, and polyisoprenoids). Unlike the other naturally occurring biological polymers, however, the PHA polymers are thermoplastic, i.e. they can be repeatedly softened with heat and hardened with cooling. As such, these polymers can be processed much like the plastics we use today.
Tepha’s biomaterials are produced by proprietary transgenic fermentation processes, similar in some respects to those used to produce biopharmaceuticals, but with substantially higher yields of product — often reaching 50 grams or more of biomaterial per liter. The company is able to control the composition of the biomaterial through the appropriate selection of genes, production vehicles, feedstocks, and pathway engineering methods.
Use of Tepha’s PHA polymers presents significant advantages in medical applications. Studies have shown that inside the body, the company’s biomaterials are biocompatible and non-inflammatory. They degrade by cell friendly processes into metabolites that already exist in humans (while some of the competing biomaterials, in contrast, release highly inflammatory acids that impair this process). The degradation process is particularly important for tissue engineering, where cells need an optimal environment for tissue regeneration. Typically, degradation rates of Tepha’s PHA biomaterials can range from about six weeks to over a year, allowing the Company to develop its biomaterials for products requiring prolonged strength retention, such as sutures for use in orthopedic procedures or materials for ligament repair.
Until recently, the widespread use of such biomaterials had been limited by the available production technology. However, in the 1980’s researchers at the Massachusetts Institute of Technology made a major breakthrough in the development of new biological production systems, when they successfully isolated the genes responsible for making these polymers in microorganisms. Our sister company, Metabolix, Inc. (Cambridge, MA) first took up the challenge for using this discovery to develop transgenic systems for the commercial production of such polymers, and the firm successfully developed several transgenic fermentation methods for producing different polymers.
The company is working on incorporating polyhydroxyalkanoates into a variety of implantable medical devices, such as artificial cardiac valves and vascular grafts.
Tepha Inc.’s (Cambridge, MA) website…
FDA press release…
(hat tip: Genetics and Health)