>>40671968

there’s a bioluminescent jellyfish which is the natural host of a protein called gfp (green fluorescent protein). you can transform e. coli k12 with the gfp plasmid using kits from a website known as the odin.

this will cause the bacteria to exhibit fluorescence. if you breed protozoa or ciliates and feed them the transformed bacteria, they can also exhibit fluorescence. you can use a 490nm led to excite the fluorescence.

unfortunately, leds produce a wide, divergent beam like a flashlight. using an aspheric lens, you can collimate the led into a parallel beam. then, if you add a excitation filter specifically a bandpass filter, you can trim the LED’s output to a specific wavelength (in this case 490 nm)

then, if you use a dichroic mirror you can reflect that filtered, collimated beam through the objective lenses onto the microscope slide, exciting the fluorophores in the sample resulting in really cool images.

here's a good video that goes into fluorescence microscopy in general:

https://www.youtube.com/watch?v=-ypA5fSVUlE