A device for interfacing with an internal biological tissue , the device comprising: a flexible and stretchable substrate having an inner surface and an external surface , wherein the inner surface defines an enclosure to enclose the internal biological tissue ; a flexible and stretchable electronic device or device component comprising one or more sensors , actuators or both supported by the inner surface of the flexible or stretchable substrate ; the sensors , the actuators or both comprising one or more inorganic semiconductor components, one or more metallic components, or one or more inorganic semiconductor components and one or more metallic components; wherein at least a portion of the inorganic semiconductor components, the metallic components or both have a thickness less than or equal to 500 microns; and wherein the flexible and stretchable substrate and the electronic device or device component provide a net bending stiffness of the system low enough such that the inner surface of the substrate is capable of establishing conformal contact with at least 70% of an outer surface of the internal biological tissue , wherein the flexible and stretchable substrate and the electronic device or device component generates a contact force generated by an elastic force of the enclosure in an expanded state wherein the contact force corresponds to a contact pressure that is sufficiently low to avoid an adverse physiological response from the internal biological tissue and remains sufficiently high to maintain said conformal contact ; wherein the contact pressure is greater than or equal to 10 Pa and less than or equal to 1 kPa and is substantially uniformly distributed over an outer surface of the internal biological tissue in conformal contact with the flexible and stretchable substrate ; wherein a peak pressure is less than or equal to 3 times the contact pressure averaged over the outer surface of the internal biological tissue in conformal contact with the flexible and stretchable substrate . a flexible and stretchable substrate having an inner surface and an external surface , wherein the inner surface defines an enclosure to enclose the internal biological tissue ; a flexible and stretchable electronic device or device component comprising one or more sensors , actuators or both supported by the inner surface of the flexible or stretchable substrate ; the sensors , the actuators or both comprising one or more inorganic semiconductor components, one or more metallic components, or one or more inorganic semiconductor components and one or more metallic components; wherein at least a portion of the inorganic semiconductor components, the metallic components or both have a thickness less than or equal to 500 microns; and wherein the flexible and stretchable substrate and the electronic device or device component provide a net bending stiffness of the system low enough such that the inner surface of the substrate is capable of establishing conformal contact with at least 70% of an outer surface of the internal biological tissue , wherein the flexible and stretchable substrate and the electronic device or device component generates a contact force generated by an elastic force of the enclosure in an expanded state wherein the contact force corresponds to a contact pressure that is sufficiently low to avoid an adverse physiological response from the internal biological tissue and remains sufficiently high to maintain said conformal contact ; wherein the contact pressure is greater than or equal to 10 Pa and less than or equal to 1 kPa and is substantially uniformly distributed over an outer surface of the internal biological tissue in conformal contact with the flexible and stretchable substrate ; wherein a peak pressure is less than or equal to 3 times the contact pressure averaged over the outer surface of the internal biological tissue in conformal contact with the flexible and stretchable substrate . <EOS>