QuickXL: An Open-source Ultraviolet Irradiation Device with Programmable Exposure and Active Cooling for Nucleic Acid Crosslinking

Accessible and reproducible ultraviolet (UV) exposure is important for psoralen-mediated RNA photocrosslinking. We describe an open-source laboratory irradiation device based on 24 nominally 365–370 nm light-emitting diode modules arranged as two selectable 12-emitter series arrays with separate drivers. A Nano-compatible microcontroller, four pushbuttons and an OLED display provide user-programmable light-on and light-off intervals and an elapsed-time limit. The arrays share a fan-cooled aluminum heatsink and sample chamber, and the device can operate inside a 4 °C refrigerator to limit sample warming. A 3D-printed enclosure incorporates a sliding cover and interchangeable tube and microplate configurations with an approximately 10 mm emitter-to-sample spacing. The design supports inexpensive, configurable irradiation for nucleic-acid sample preparation, and can be adapted for other light-triggered activation of biological samples.