A device for manipulating microdroplets using optically-mediated electrowetting consisting essentially of • a first composite wall comprised of: • a first transparent substrate • a first transparent conductor layer on the substrate having a thickness in the range 70 to 250nm; • a photoactive layer activated by electromagnetic radiation in the wavelength range 400-1000nm on the conductor layer having a thickness in the range 300-1000nm and • a first dielectric layer on the conductor layer having a thickness in the range 120 to 160nm; • a second composite wall comprised of: • a second substrate; • a second conductor layer on the substrate having a thickness in the range 70 to 250nm and • a second dielectric layer on the conductor layer having a thickness in the range 120 to 160nm wherein the exposed surfaces of the first and second dielectric layers are disposed less than 10μm apart to define a microfluidic space adapted to contain microdroplets; • an A/C source to provide a voltage of between 10V and 50V across the first and second composite walls connecting the first and second conductor layers; • at least one source of electromagnetic radiation having an energy higher than the bandgap of the photoexcitable layer adapted to impinge on the photoactive layer to induce corresponding ephemeral electrowetting locations on the surface of the first dielectric layer and • means for manipulating the points of impingement of the electromagnetic radiation on the photoactive layer so as to vary the disposition of the ephemeral electrowetting locations thereby creating at least one electrowetting pathway along which the microdroplets may be caused to move; and wherein the device is configured to perform chemical analyses carried out on multiple analytes simultaneously. • a first composite wall comprised of: • a first transparent substrate • a first transparent conductor layer on the substrate having a thickness in the range 70 to 250nm; • a photoactive layer activated by electromagnetic radiation in the wavelength range 400-1000nm on the conductor layer having a thickness in the range 300-1000nm and • a first dielectric layer on the conductor layer having a thickness in the range 120 to 160nm; • a first transparent substrate • a first transparent conductor layer on the substrate having a thickness in the range 70 to 250nm; • a photoactive layer activated by electromagnetic radiation in the wavelength range 400-1000nm on the conductor layer having a thickness in the range 300-1000nm and • a first dielectric layer on the conductor layer having a thickness in the range 120 to 160nm; • a second composite wall comprised of: • a second substrate; • a second conductor layer on the substrate having a thickness in the range 70 to 250nm and • a second dielectric layer on the conductor layer having a thickness in the range 120 to 160nm • a second substrate; • a second conductor layer on the substrate having a thickness in the range 70 to 250nm and • a second dielectric layer on the conductor layer having a thickness in the range 120 to 160nm wherein the exposed surfaces of the first and second dielectric layers are disposed less than 10μm apart to define a microfluidic space adapted to contain microdroplets; • an A/C source to provide a voltage of between 10V and 50V across the first and second composite walls connecting the first and second conductor layers; • at least one source of electromagnetic radiation having an energy higher than the bandgap of the photoexcitable layer adapted to impinge on the photoactive layer to induce corresponding ephemeral electrowetting locations on the surface of the first dielectric layer and • means for manipulating the points of impingement of the electromagnetic radiation on the photoactive layer so as to vary the disposition of the ephemeral electrowetting locations thereby creating at least one electrowetting pathway along which the microdroplets may be caused to move; and • an A/C source to provide a voltage of between 10V and 50V across the first and second composite walls connecting the first and second conductor layers; • at least one source of electromagnetic radiation having an energy higher than the bandgap of the photoexcitable layer adapted to impinge on the photoactive layer to induce corresponding ephemeral electrowetting locations on the surface of the first dielectric layer and • means for manipulating the points of impingement of the electromagnetic radiation on the photoactive layer so as to vary the disposition of the ephemeral electrowetting locations thereby creating at least one electrowetting pathway along which the microdroplets may be caused to move; and wherein the device is configured to perform chemical analyses carried out on multiple analytes simultaneously.