Toray Industries, Inc. (head office: Chuo-ku, Tokyo; President: Akihiro Nikkaku; hereinafter referred to as "Toray") today announced that it has succeeded in creating a novel bioabsorbable polymer with skin-like flexibility that recovers to its original shape even after being stretched 10 times the original length by utilizing its proprietary functional polymer design technology. Moreover, it has also identified a technology to improve the degradation speed of the polymer by 10 times through hydrolysis. The company will accelerate the development of polymers based on this technology for regenerative medicine and other medical uses and expand its applications into various industrial uses.
Originally, polylactic acid and polyglycolic acid, which are bio-absorbable polymers, tended to form crystals (crystallinity) and become hard, which made it difficult to provide both flexibility and rupture resistance properties.
Toray developed a special copolymerization method using lactide, dimers of lactic acid, and caprolactone, and realized both flexibility and rupture resistance enabling recovery without rupture even after being stretched 10 times the original length. Further, by highly controlling the hydrolysis of this polymer, it created a bioabsorbable polymer with the decomposition speed improved 10 times.
The technology is expected to be applied to tissue reconstruction treatment such as regenerative medicine, where flexibility and rupture resistance to follow the movements of organs and biological tissues are required. For example, polymer-based medical materials temporarily compensate as a scaffolding for injured flexible tissues to regenerate. The materials have advantages; there is no concern of residual and repeated surgery is also available as necessary, because the materials degrade after they complete the role. As they are considered to be highly versatile, they are expected to be applied to a wide range of fields in addition to the medical use. The key points of the technologies are described below.
1. Technology to modify the bioabsorbable and mechanical characteristics
From early, Toray has focused on improving the mechanical characteristics of bio-absorbable polymers and has been creating bio-absorbable polymers, boasting flexibility and restoration property upon being compressed, by combining units of lactic acid, polyglycolic acid, caproic acid and ethylene glycol. In this research, the company succeeded in developing bio-absorbable polymer that has all of flexibility, rupture resistance and restoration property by significantly reducing its crystallinity using an unprecedented, special copolymerization method born from further developing the above conventional technologies.
2. Technology to control hydrolysis
The copolymer of lactide and caprolactone takes time for hydrolysis because it is highly hydrophobic and it repels water. Toray, by controlling the amount of the ethylene glycol unit, improved the degradability by 10 fold without impacting the aforementioned mechanical characteristics.
When this developed product was coated on the outer surface of a 3mm diameter artificial vascular graft made from polyester fiber, in a desk study it didn’t buckle even when bent, and flexibly followed the movement of the vascular graft. Further, in animal experiments, we successfully demonstrated that the vascular graft was patent after six months implantation due to vascular cell migration into from around the vascular graft as the developed material degraded, and subsequent vascular tissue regeneration on the scaffold of the graft.
Toray will pursue further development of this bio-absorbable polymer as a scaffolding material in regenerative medicine that would regenerate the flexible organizations and tissues of not only blood vessels but also skin, digestive and urinary organs as well as muscles.
Toray, in the Toray Group Sustainability Vision announced in July 2018, has declared contributing to better medical care and hygiene as one of the tasks that the Group should undertake leveraging its innovative technologies and advanced materials. The Group will continue to aim for sustainable growth expansion along with making social contribution by realizing the Corporate Philosophy of “contributing to society through the creation of new values” through the promotion of development of high value-added medical materials utilizing its advanced materials technologies.
