This article illustrates the development and preliminary results of SELINE, a self-opening neural interface. The advantages of this innovative neural interface are: higher selectivity due to its three-dimensional structure and efficient anchorage system to the nervous tissue. The device is made of polyimide that is a lightweight, flexible and biocompatible polymer. The electrode has been microfabricated using lithographic techniques; electrical and mechanical tests have been performed to evaluate the integrity of the device. Successful results have been obtained in the development of the electrode with excellent mechanical and electrical properties.