Medical grade adhesive used in microchannel array in prosthetics
Researchers at MIT used Master Bond epoxy EP3HTSMed in the construction of an implantable microarray device.
Researchers at Massachusetts Institute of Technology sought to devise and test a novel microchannel array to assess the extent of nerve regeneration in a prosthetic device. The devices constructed utilised Master Bond EP3HTSMed, a USP Class VI certified, highly conductive epoxy for use in medical device assembly. Developed for rigorous bonding and sealing in demanding manufacturing applications, this epoxy system features a rapid cure schedule and a tensile shear strength exceeding 1,000 psi. It is a silver-filled epoxy adhesive/sealant with a volume resistivity less than 0.001 ohm cm. Serviceable over the wide temperature range of -60°F to 400°F, EP3HTSMed is resistant to severe thermal cycling and many chemicals including water, fuels, oil, and most organic solvents.
Adhesives and sealants used in the construction of implantable medical devices must meet strict biocompatibility and toxicity requirements. The United States Pharmacopeia, USP, maintains rigorous protocols that must be undergone prior to the use of any plastic, rubber, adhesive or sealant in a medical device—depending on the nature of the product, different requirements must be met. Of the USP’s requirements, Class VI certification is the most rigorous and requires tests to assure that the material or its leachates will impart no systemic toxicity to the subject.
Recent advances in robotics have been used to improve the functionality and utility of prosthetic devices for persons with amputations. Despite the advancements, the integration of upper and lower limb prostheses still faces many challenges in enabling truly biomimetic functionality between the user and the prosthetic device. An ideal prosthesis would possess bidirectional neural communication—existing neural signals from the user could be interpreted and sent to the device resulting in actuation while sensors present on the device itself would send signals back to the user’s nervous system providing sensory feedback. Long-term efficacy also requires that the device have a high biocompatibility, enable nerve regeneration, and impart limited pathology to the remaining nerve fibres and surrounding tissues.
Five months after implantation of the devices into the test animals, the authors conducted tests to ascertain the extent of nerve regeneration within the channels using EMG recordings and immunofluorescence. To download the full case study, its application, key parameters, requirements and results, please click here.