Antifibrotic Coatings

Overcoming fibrotic encapsulation of implantable medical devices

All materials and medical devices implanted in the body generate a foreign body response (FBR). The FBR results in the formation of a collagenous capsule developing around the material in a process called fibrotic encapsulation. For numerous implantable medical devices – including blood glucose sensors, cochlear implants and peripheral nerve repair guides – fibrotic encapsulation can adversely affect the device function and can lead to failure. For peripheral nerve repair in particular, fibrotic encapsulation results in the formation of a neuroma impenetrable to the regrowing nerve ends. Our antifibrotic technology has demonstrated the ability to significantly reduce fibrotic encapsulation around a subcutaneous model implant in mice after 6 weeks in vivo.

During the conduct of this project, we were able to demonstrate that the antifibrotic peptide, which is the basis of our technology, can be incorporated into a polymer (PLGA) suitable for application to medical devices, and that upon release from that coating it maintains its activity.  Using an implanted osmotic minipump in an in vivo murine model information on the amount of peptide required to achieve a significant reduction in the thickness of the fibrotic capsule was obtained, along with the length of release time required to achieve the effect. Additionally, a slot-die coating method was developed to apply patterned coatings of polymer (using 65% w/v PLGA in DMF) to collagen nerve guidance conduit sheets suitable for the controlled release of the peptide.

For further information please contact Helmut Thissen, CSIRO