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 six weeks in vivo.

The project described herein has two components. In the first phase, we will determine the maximum effectiveness of our technology in regard to reducing fibrotic encapsulation in vivo, highlighting the effective dose and requirements related to drug delivery duration. This will be conducted in a murine model where an implantable minipump will enable us to administer controlled doses at the implant site. In the second phase, the optimised parameters will then be directly translated to endow the current generation of peripheral nerve repair guides with antifibrotic properties. A head-to-head comparison between the standard and modified guides will be conducted in an established large animal model for peripheral nerve damage. A successful outcome will demonstrate a reduction of the fibrotic capsule by at least fifty per cent, increased nerve conductance by at least ten per cent, improved nerve regrowth parameters (axon quantification relative to fibrotic tissue infiltration) and functional limb recovery observed ten per cent earlier than the control guide.

For further information please contact Helmut Thissen, CSIRO.