<p>The severity of damage done to a peripheral nerve can range from the inhibition of fine motor movements to the complete loss of feeling and function in the affected extremity. The current standard for nerve repair is the surgical implantation of either an allograft or autograft, however, issues such as the minimal recovery of function have led to continued research into a more efficient and rapid nerve regeneration method using manufactured conduits and scaffolds. Nerve guide conduits (NGC) are a popular alternative treatment in nerve regeneration and repair, specifically in the case of large nerve gaps (30mm), where the rate of regeneration and repair is significantly limited. Research has moved into the functionalization and design of these NGCs, combining several aspects, such as topographical designs for optimal growth, increasing axonal regeneration rate, and the combination and specific release delivery system for drugs and growth factors that could assist in repair. The conductivity of these NGCs is also a highly desirable property, as slight electrical stimulation enhances regular body functions such as muscle contractions. Electrical stimulation has been shown to improve the growth time of regenerating nerves. In addition, the need for biocompatible and biodegradable conductive polymers has progressed rapidly. Aerosol jet printing is a popular manufacturing method for the production of sensors and offers the capabilities to direct-write, small scale printing and while this technology has largely focused on printing metal inks, the use in effective printing of biomaterials has been limited. Polycaprolactone (PCL) is an FDA-approved polymer for use in biomedical applications and has been studied using electrohydrodynamic printing technology. Research into this polymer has shown that it shows little to no biological response in tissues, limiting inflammation and reaction, and has been described as a good candidate material in the use for biomedical applications. To date, PCL/ polypyrrole (PPy) copolymers have been used in bioprinting scaffolds for tissue engineering, specifically in peripheral nerve injury, but have yet to be printed using an aerosol jet printer. Therefore, the feasibility of printing a PCL/PPy bio conductive polymer blend using an aerosol jet printer will be studied. Different formulations will then be compared which consist of PPy-b-PCL 0.5, 1, and2% v/v. Conductivity will be measured using a conductivity meter and compared to values obtained from electrohydrodynamic printer. Given successful implementation of an electrically stimulating layer to a nerve guide conduit has the potential to increase the regeneration rate of peripheral nerves that have been damaged, decreasing the likelihood of loss of function.</p>

Printability and Functionality Study of Polycaprolactone and Polypyrrole Copolymers for Nerve Guide Conduits Using Aerosol Jet Printing

Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2021/volume/85543

ASME 2021 International Mechanical Engineering Congress and Exposition (IMECE2021)

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