Ziya Baghmanli

PEDOT electrochemical polymerization improves electrode fidelity and sensitivity.

Background: The goal of the authors is to restore fine motor control and sensation for high-arm amputees. They developed a regenerative peripheral nerve interface with the aim of attaining closed loop neural control by integrating directly with the amputees residual motor and sensory peripheral nerves. PEDOT, poly(3,4-ethylenedioxythiophene), has both electrical and ionic conduction characteristics. This hybrid character could help bridge the salutatory conduction of the nervous system to an electrode. The purpose of this study was to determine whether electrodes polymerized with PEDOT have improved ability to both record and stimulate peripheral nerve action potentials. Methods: Impedance spectroscopy and cyclic voltammetry were performed on electrodes before and after polymerization to measure electrode impedance and charge capacity. Both recording needle and bipolar stimulating electrodes were polymerized with PEDOT. Plain and PEDOT electrodes were tested using rat (n = 18) in situ nerve conduction studies. The peroneal nerve was stimulated using a bipolar electrode at multiple locations along the nerve. Action potentials were measured in the extensor digitorum longus muscle. Results: Bench testing showed PEDOT electrodes had a higher charge capacity and lower impedance than plain electrodes, indicating significantly improved electrode fidelity. Nerve conduction testing indicated a significant reduction in the stimulus threshold for both PEDOT recording and PEDOT stimulatory electrodes when compared with plain electrodes, indicating an increase in sensitivity. Conclusions: PEDOT electrochemical polymerization improves electrode fidelity. Electrodes that have been electropolymerized with PEDOT show improved sensitivity when recording or stimulating action potentials at the tissue–electrode interface.

Biological and Electrophysiologic Effects of Poly(3,4-ethylenedioxythiophene) on Regenerating Peripheral Nerve Fibers

Background: Uninjured peripheral nerves in upper-limb amputees represent attractive sites for connectivity with neuroprostheses because their predictable internal topography allows for precise sorting of motor and sensory signals. The inclusion of poly(3,4-ethylenedioxythiophene) reduces impedance and improves charge transfer at the biotic-abiotic interface. This study evaluates the in vivo performance of poly(3,4-ethylenedioxythiophene)–coated interpositional decellularized nerve grafts across a critical nerve conduction gap, and examines the long-term effects of two different poly(3,4-ethylenedioxythiophene) formulations on regenerating peripheral nerve fibers. Methods: In 48 rats, a 15-mm gap in the common peroneal nerve was repaired using a nerve graft of equivalent length, including (1) decellularized nerve chemically polymerized with poly(3,4-ethylenedioxythiophene) (dry); (2) decellularized nerve electrochemically polymerized with poly(3,4-ethylenedioxythiophene) (wet); (3) intact nerve; (4) autogenous nerve graft; (5) decellularized nerve alone; and (6) unrepaired nerve gap controls. All groups underwent electrophysiologic characterization at 3 months, and nerves were harvested for histomorphometric analysis. Results: Conduction velocity was significantly faster in the dry poly(3,4-ethylenedioxythiophene) group compared with the sham, decellularized nerve, and wet poly(3,4-ethylenedioxythiophene) groups. Maximum specific force for the dry poly(3,4-ethylenedioxythiophene) group was more similar to sham than were decellularized nerve controls. Evident neural regeneration was demonstrated in both dry and wet poly(3,4-ethylenedioxythiophene) groups by the presence of normal regenerating axons on histologic cross-section. Conclusions: Both poly(3,4-ethylenedioxythiophene) formulations were compatible with peripheral nerve regeneration at 3 months. This study supports poly(3,4-ethylenedioxythiophene) as a promising adjunct for peripheral nerve interfaces for prosthetic control and other biomedical applications because of its recognized ionic-to-electronic coupling potential.

Prosthetic Material Properties Affect Neuroma Formation: A 6-Month Study

IntroductIon: Improvement in survival and patient outcomes following regionalization of trauma care services has been demonstrated by strong evidence. The implementation of integrated regional trauma care systems has involved changes aimed at combining all services within a region in a coordinated network assuring that patients are treated at appropriate facilities by experienced personnel. This has led to the development of specialized trauma centres within regional trauma systems. The purpose of the study was to measure: 1) short-term survival, 2) post-operative complications, and 3) immediate re-intervention rates of digital replantation surgeries following the implementation of a regionalized program aimed at covering the Quebec population.

Abstract P3: A Ceiling Effect Exists for the Number of Nerves That Will Neurotize a Regenerative Peripheral Nerve Interface Device

M arch 7 – 9, 2014 findings support the novel use of partial muscles in the construction of bio-artificial interfaces necessary for the surgical integration of robotic devices with the residual limbs of amputees. As this was a short-term pilot study, longer-term studies with larger sample sizes are warranted to determine how the effects of muscle cut and anchoring can be used for signal optimization in prosthetic control.

Effect of Polymerization Methods on Peripheral Nerve Regeneration

concluSIon: Seprafilm decreased periprosthetic capsular thickness in the rat model without undue inflammation. Clinically, the application of Seprafilm resulted in no adhesion formation between the delayed flap and surrounding tissues, which facilitated reoperation. We speculate that Seprafilm serves as a barrier to fibrotic healing, and thereby may enhance the development of preferential blood supply of a delayed flap.

70A: IMPACT OF PEDOT ON PERIPHERAL NERVE REGENERATION AND MUSCLE REINNERVATION

Introduction: Our ultimate goal is to innervate a living interface for electrically connecting amputated limbs to prostheses. The purpose of this study is to characterize the impact of an electrically conductive polymer poly (3,4-ethylenedioxythiophene) (PEDOT) on peripheral nerve regeneration and muscle reinnervation. PEDOT reduces electrode impedance at sites where bioelectric signals are transduced to electronic signals such as at the interface between neural tissue and microelectrodes. We test the null hypotheses that the presence of PEDOT at the site of nerve regeneration has no impact on peripheral nerve regeneration or subsequent end organ function.