A programmable LED device that illuminates multiple spatial locations (termed wells) with user-defined light patterns whose intensity can be modulated as a function of space and time. The devices are used for optogenetic stimulation of tissue culture plates (24-well and 96-well) kept in a heated and humidified tissue culture incubator, as well as photopatterning of hydrogels. In brief, light from LEDs passes through optical elements that ensure uniform illumination of each well. Parameters of the optical system, such as LED configuration, optical diffuser elements, materials, and geometry, were modeled and optimized using the optical ray tracing software Zemax OpticStudio. An electronics subsystem allows programmed control of illumination intensity and temporal sequences, with independent control of each well. Spatial precision is conveyed through a photomask attached to the culture plate. The hardware design also includes a cooling system and vibration isolation to reduce heating and damage to the sample. Lastly, a graphical user interface (GUI) was used to wirelessly program the illumination intensity and temporal sequences for each well. The devices can thus illuminate 24 independent channels with visible, NIR, or UV light with intensity ranges of 0 to 20-100 microwatts per millimeter-squared with 16-bit intensity resolution, and a temporal resolution of 1 millisecond and spatial resolution of 100 microns. In summary, the device allows uniform illumination of multiple wells for multiplexed photoactivation or photopolymerization of various substrates (light-responsive bacterial or mammalian cells grown in tissue culture, hydrogels, dyes, etc) with user-defined patterns. The device can be combined with a robotic handler, microscope, spectrometer, etc, to enable high-throughput illumination and simultaneous recording of the sample.
Can be used to illuminate any desired substrate with continuous light, pulsed light, or arbitrary spatial and temporal patterns of light. The proposed applications include optogenetic control of developmental signaling in embryonic stem cells (with blue light) and photopatterning of hydrogels to control stiffness (with UV light). Can be generally used for photostimulation of endogenous light-responsive proteins or molecules to control phototropic growth, phototoxicity, or signaling. Various organisms, such as algae cyanobacteria and plants, are responsive to light and such devices can be used to control their growth, migration, behavior, molecular signaling, and death. The device can be used to activate exogenously expressed optogenetic systems or light-activated sensors in bacteria, yeast, plants/seeds, or mammalian cell cultures, both in 2D culture, 3D gels, or small bioreactors. Can also be used for UV curing of photopolymers at defined light dosages. Given the multiplexed, 24-channel capability of the board (which can be further extended by chaining multiple LED drivers), can enable high-throughput studies with applications in drug screening, genetic or transcriptomic screens, directed evolution of sensors or fluorescent proteins, and photoxicity screens. The device can be combined with a robotic handler, microscope, spectrometer, etc, to enable high-throughput illumination and simultaneous recording. Further improvements in mask manufacturing resolution can also enable higher resolution patterning and grayscale modulation.