A photoactivation apparatus (200) separately delivers light to a plurality of wells of a multiwell plate (110). The device-includes a plurality of light emitting diodes (210) attached to a first surface of a substrate (220) such that when the photoactivation apparatus is positioned on the multiwell plate each of the light emitting diodes delivers light to one corresponding well. The light emitting diodes (210) may extend at least partially into the wells of the multiwell plate. A heat sink (250) and fan may be provided on the device to dissipate heat generated by the light emitting diodes. The components are preferably enclosed in a conveniently-sized housing (270). The housing may include one or more grips and air vents. The apparatus includes an interlocking lip (230) defining a recess which is sized to receive at least a portion of the multiwell plate. A power supply connected to the apparatus and configured to provide an equal voltage across each of the light emitting diodes.