Fluorescent Imaging with LED Lamps

A blue LED headlamp (Topme, purchased from www.amazon.com, advertised as a fishing headlamp) or a multi-color LED flashlight (Lumenshooter, purchased from www.amazon.com, advertised as a tactical flashlight) was used for GFP illumination. To reduce stray light in the green and yellow wavelengths, theater stage gel lighting film (Rosco #4990, CalColor Lavender) was cut and inserted between the LED and the focusing lens of the headlamp. Rosco #14 (Medium Straw) and #312 (Canary) theater stage lighting gel film were used individually or in combination as emission filters. The LED lamp was held at approximately a 45-degree angle above and within 3–6 inches of the specimens. Emission filters were placed between the acrylic platform and the clip-on lens. For imaging of red fluorescent proteins, Rosco #88 (Light Green) and #89 (Moss Green) were used for illumination (excitation filters) along with #19 (Fire) as an emission filter. All Rosco filters were purchased from www.stagelightingstore.com or www.bhphotovideo.com. A Vernier Emissions Spectrometer (VSP-EM, www.vernier.com) was used to assess the effects of excitation filters. Vernier Spectral Analysis software (version 4.11.0–1543) was used to acquire and convert data to .csv format, which was then imported into Microsoft Excel and subsequently used to make plots using GraphPad Prism (version 7.0, GraphPad). A Vernier LabPro coupled to a light sensor (Vernier LS-BTA) was used to assess light intensity of blue LED flashlights in combination with Vernier Logger Pro 3 software (version 3.16.2). A multimeter (Amprobe 30XR-A) was used to measure the current draw between the battery and LED on the blue LED headlamp.