This invention relates to a substrate layer structure adapted to carry electronic device, or components, or electro-mechanical, or electro-chemical sensors, or a combination thereof, and adapted to be attached to a surface of a human or
animal body or
biological species. The surface of the flexible substrate layer structure is a patterned structure of pre-fixed geometry-formed by one or more slits, but this geometry being selected such that the stretchability of the substrate layer structure becomes adapted to the geometry of the
body surface under it.