A biomedical device comprising: a flexible or stretchable substrate (30, 35); a stretchable or flexible electronic circuit comprising an array of electronic devices, the electronic devices including: one or more flexible or stretchable light emitting diode arrays supported by said flexible or stretchable substrate (30, 35), each flexible or stretchable LED array comprising one or more inorganic LEDs having an average thickness less than or equal to 100 μm; and one or more flexible or stretchable photodetector arrays supported by said flexible or stretchable substrate (30, 35), each flexible or stretchable PD array comprising one or more inorganic semiconductor elements having an average thickness less than or equal to 100 μm; one or more barrier layers at least partially encapsulating said one or more flexible or stretchable light emitting diode arrays and said one or more flexible or stretchable photodetector arrays, wherein said barrier layer prevents water from said environment from contacting at least a portion of said inorganic LEDs of said one or more flexible or stretchable light emitting diode arrays and at least a portion of said inorganic semiconductor elements of said one or more flexible or stretchable photodetector arrays; a controller for controlling functionality of the stretchable or flexible electronic circuit, wherein the controller receives information corresponding to an intensity of electromagnetic radiation received by the photodetectors, characterized in that each LED independently produces infrared electromagnetic radiation, visible electromagnetic radiation, ultraviolet electromagnetic radiation, broadband electromagnetic radiation or narrowband electromagnetic radiation. a flexible or stretchable substrate (30, 35); a stretchable or flexible electronic circuit comprising an array of electronic devices, the electronic devices including: one or more flexible or stretchable light emitting diode arrays supported by said flexible or stretchable substrate (30, 35), each flexible or stretchable LED array comprising one or more inorganic LEDs having an average thickness less than or equal to 100 μm; and one or more flexible or stretchable photodetector arrays supported by said flexible or stretchable substrate (30, 35), each flexible or stretchable PD array comprising one or more inorganic semiconductor elements having an average thickness less than or equal to 100 μm; one or more flexible or stretchable light emitting diode arrays supported by said flexible or stretchable substrate (30, 35), each flexible or stretchable LED array comprising one or more inorganic LEDs having an average thickness less than or equal to 100 μm; and one or more flexible or stretchable photodetector arrays supported by said flexible or stretchable substrate (30, 35), each flexible or stretchable PD array comprising one or more inorganic semiconductor elements having an average thickness less than or equal to 100 μm; one or more barrier layers at least partially encapsulating said one or more flexible or stretchable light emitting diode arrays and said one or more flexible or stretchable photodetector arrays, wherein said barrier layer prevents water from said environment from contacting at least a portion of said inorganic LEDs of said one or more flexible or stretchable light emitting diode arrays and at least a portion of said inorganic semiconductor elements of said one or more flexible or stretchable photodetector arrays; a controller for controlling functionality of the stretchable or flexible electronic circuit, wherein the controller receives information corresponding to an intensity of electromagnetic radiation received by the photodetectors,