Bidirectional bionic limbs: a perspective bridging technology and physiology.

Precise control of bionic limbs relies on robust decoding of motor commands from nerves or muscles signals and sensory feedback from artificial limbs to the nervous system by interfacing the afferent nerve pathways. Implantable devices for bidirectional communication with bionic limbs have been developed in parallel with research on physiological alterations caused by an amputation. In this perspective article, we question whether increasing our effort on bridging these technologies with a deeper understanding of amputation pathophysiology and human motor control may help to overcome pressing stalls in the next generation of bionic limbs.

Design of Experiment Evaluation of a 2.5D Printing Process for Implantable PDMS-based Neural Interfaces.

Current laser fabrication processes for PDMS-based neural interfaces are associated with excessive costs, due to time-consuming manual handling and expensive machinery. The products of this process, specifically embedded metallic electrical tracks, are prone to breakage under mechanical loading, as well as delamination from their surrounding PDMS substrates. In this work, we develop an alternative 2.5D printing process, using electrically conductive PDMS material for the tracks. The entire electrode was fabricated in a custom-made printing setup, which features the possibility of rapid prototyping. The printing performance of the selected materials was evaluated with the aid of statistical methods for experimental design. We found optimal printing parameters for conductive and non-conductive PDMS which allows the fabrication of flexible and stretchable neural interfaces, while simultaneously minimizing the track resistivity.Clinical Relevance- 2.5D printing processes pave the way for individualized neural interfaces to suit the specific needs of every single patient.

Design of experiment evaluation of sputtered thin film platinum surface metallization on alumina substrate for implantable conductive structures.

Reliability and reproducibility of implants and their fabrication are highly depending on the assembly and packaging procedures. Individual fabrication skills like soldering introduce inaccuracies and should be avoided as much as possible. Screen printing is often utilized for the metallization of ceramics. Using platinum/gold (Pt/Au) paste liquidus diffusion leads to a low adhesion strength of the Pt/Au pads after soldering. As an alternative, sputtering of thin film surface metallization was investigated. However, this alternative comes with a huge amount of different layer and parameter setups. In order to keep the amount of experiments and data acquisition in a reasonable magnitude, the Design of Experiment (DoE) evaluation displays a powerful tool. We found an optimal layer setup that maximizes the adhesion strength of the layer, while simultaneously minimizing the sheet resistance and removing the dependency of soldering time.