This work provides a simple framework to optimize the design of self penetrating neural interfaces. First, an assessment of interactions between electrodes and peripheral nerves is provided and related to the instantaneous elasticity of the tissue. Then, the elastic instability of electrodes is considered, because it is the main cause of failure of implants. The connection between the previous two sections, integrated with an assessment of a safety coefficient for in-vivo implants, allows to predict some important parameters of a reliable electrode: its maximum slenderness ratio (SR) and the minimum Young modulus of its main shaft
