Team:Pasteur Paris/Device
We designed a global proposition, thinking of dimensions, materials, fabrication processes, always taking into consideration the industrial and medical feasibility and the user’s comfort. Our system includes an implantation stem featuring our engineered biofilm, an interface device to collect and process the signal from nerves, and also connect the future prosthesis. A charging station and an app are also part of our setup.
Implanting a functional stem
To connect our device to the user’s stump, we designed a technical piece, a fully functional stem, that is osseointegrated.
This internal device needs an extremely high precision for machining parts. Indeed, the biofilm and the membrane’s nanometric scales and necessity to extend a member leads to constraining strength and precision’s placement. Directly in contact with bone, the sintered ceramic part links the bone and the titanium stem together (Figure1). Where the stem emerges from the bone, its diameter expands, increasing from 6 mm to 10 mm. The biofilm occupies the space in the few centimeters available between the bone and skin. It is contained by a semi-permeable membrane. The latter, in PEDOT: PSS, is the surface upon which the nerves will come to fixate. This also allows the electric nerve current to transmit to an electrical current on the membrane. This membrane is placed around the tube and will conduct the signal to the outside (Figure 2).
The titanium implanted tube, which is biocompatible, has a resistance as measured by it Young’s modulo of 193 GPa, and a low density of 4510 Kg/M3 compared to biocompatible stainless steel with 114 GPa and 800 Kg/M3.
Connecting the device to the stump
Once the nerves signal is conducted by the electrical wires, it has to be treated and amplified. This is done into an interface device placed between the stump and the bionic prosthesis.
As for the NeuronArch interface device, we chose ABS (Acrylonitrile-Butadiene-Styrene) as the main material. We wanted an injection moldable plastic to reduce the cost of machining as well as it offered the most interesting properties for our project, among all the available materials.
Charging and synchronizing the interface device
In order to recharge the NeuronArch device, we designed an induction charging box, that includes a power outlet connectable USB-C plug. The compatible loading station is made of ABS and is used for patient data synchronization. It also features a small elevation on the housing that allows the NeuronArch interface device to be perfectly engaged and stable while charging and synchronizing. For storing cables during transportation we anticipated an elastic strip on the back of the station.
Consulting and monitoring data
