To jump from the first ideas to tangible solutions, we designed a complete system (hardware and software solutions) including:
- an implantation stem featuring our engineered biofilm
- a device making the bridge between the stump and a bionic prosthesis, to collect and process the signal from nerves
- a charging station, to recharge the device and synchronize data with a distant server
- an app / website, to monitor information, such as device’s battery level, health status, etc.
In order to design these solutions in a relevant, feasible and comfortable way, we payed strong attention to the device dimensions, ergonomics, assemblies, materials, colors, looks and feel, electronic parts, production process and costs. The following devices have been conceived and developed throught design and engineering knowledge. Skills and tools (McNeel Rhino 3D (Figure 1) for 3D modeling, Luxion Keyshot for 3D rendering), as well as scientific and industrial advice from experts were also used. Colors, materials and finishes have been chosen regarding our device constraints and thanks to material databases and color charts (Figure 2 and 3).
Figure 1: 3D Modeling of our device and charger
Figure 2: Color Research
Figure 3: Color Detail
Conceiving the functional stem
We designed a fully functional stem (Figure 4 and 5) composed of:
- a biocompatible tube made of titanium, to mechanically assemble the device to the user’s stump (1.). This material have been chosen instead of stainless steel 316L thanks to the mechanical modeling of the 3D representation of a humerus bone with a prosthesis (Download the mechanical modeling here)
- a porous ceramic part (2.), surrounding the metallic tube inside the amputee’s bone (3.) to durably and safely link the tube to the bone
- our engineered biofilm (4.), surrounding the metallic tube inside the amputee’s stump flesh
- a nanoporous membrane made of PEDOT: PSS (5.), to confine the biofilm within our system, to fixate nerves on it, and to allow the ionic current from nerves to be transformed into an electrical current, that would be processed and used to actuate a bionic prosthesis
- a thin structure (6.) that supports the nanoporous membrane and transmits electric current from nerves to the stem (7., 8.).
Figure 4: Diagram of the implantation system parts
Figure 5: Implantation cross section view
Conceiving the device
We designed an ergonomic and functional device (Figure 6) to link the stump to a bionic prosthesis, composed of:
- a three parts plastic case made of light-weight, heat and shock resistant injection moldable plastic (ABS - Acrylonitrile-Butadiene-Styrene), to safely enclose technical parts. Injection molding is a reliable process that permits a low cost mass production. Two removable shells (1.) surround the main structure (2.) to facilitate maintenance. An elastomer seal (3.) is placed between these parts and make the device waterproof. Moreover, plastic have been textured to make user’s daily interactions with his device easier
- a antibacterial ceramic shell (4.), placed between the stump and the device, to improve hygiene and to protect the user from friction
- electronic parts, to amplify and process the signal (5.), to charge the device (6., 7., 8.), to store (9.) and to send data (10.).
Figure 6: Exploded drawing of NeuronArch device
Conceiving the charging / synchronization station
We designed an easy to use charging / synchronization station (Figure 7), composed of:
- a plastic case (1., 2.) made of ABS, to safely enclose technical parts;
- electronic parts, to charge the device thanks to induction (3.) and a USB-C plug (4.), to send and receive data via wifi and bluetooth connection (5.), to save data via a micro SD card (6.), to demonstrate the charging and synchronization process via a LED ring (7.);
- an elastic strip (8.) placed at the back of the charging station, to store cables during transportation.
Figure 7: Exploded drawing of NeuronArch charging station
Conceiving the secured communication system between our device and the digital world
We designed an efficient system to allow our device to securely exchange data with the digital world. Thanks to integrated electronic parts and to the designed digital architecture, data from nerves signals, bionic prosthesis movements, and user’s health status can be recorded, stored and exchanged. An online algorithme would learn from the user on a daily basis, and improve future interactions. To do so, our communication system (Figure 8) is composed of:
- Bluetooth Low Energy, a very energy-efficient technology enabling heavy data transfer on short distance, to share daily stored data from the device to the charging station, and vice versa;
- Wifi connection, to exchange those data with the distant secure NeuronArch servers, and vice versa.
Figure 8: Communication system
Conceiving the app / website
Finally, we designed an app / website to create a user friendly interface. This app / website allows every NeuronArch user to store, monitor, understand, and share with a doctor his personal data. To do so, our app / website (Figure 9) is composed of:
- a personal home page (1.), to have a general overview regarding health data, charging level, and general notifications
- a personal dashboard (2.), to monitor recorded health data such as glycemia, blood pressure, etc.
- a medical appointment booking platform (3.), including registered primary doctor availabilities, prosthetists locations, etc.
- a unique QR code (4.), to securely share recorded personal data with the user’s doctors during appointments.
Figure 9: Diagram of the app principle screens
