Application of blue–green and ultraviolet micro-LEDs to biological imaging and detection

This paper reviews authors' laboratory's work on the development of nitride-based blue–green and ultraviolet microscale LED devices with particular classes of imaging and spectroscopic applications in cellular level biology. Starting from neuroscience, we illustrate the utility of blue–green micro-LEDs for voltage-sensitive dye imaging of individual neural cells, as well as their ultraviolet counterparts for photostimulation of neurons. Arrays of micro-LEDs are also shown to be useful in projecting spatiotemporal patterns of photoexcitation to study the visual system development in living animals. As another illustration of the utility of the emerging nitride microdevice technology, we demonstrate the application of UV micro-LED arrays in bio-sensing technology as the core of a real-time fluorescence spectroscopy biowarning system.