Isolate, prepare and image your own cheek cells at home with just a smartphone, webcam lens and a few other bits and pieces.
Step 1: Build Your #cellfie Station
The #cellfie station a very simple DIY microscope powerful enough to image human cheek cells with a smartphone. It is based on the awesome $10 smartphone microscope stage, but with some slight tweaks to the specimen stage and the higher-magnification-lens from a cheap webcam, as used in Hackteria's DIY Microscope – thanks to Marc Dusseiller for the advice (and for the original webcam lens!). All credit goes to the hacks which inspired it.
- 3 x carriage bolts (M8x150mm)
- 11 x nuts (M8)
- 12 x washers (M8)
- 1 x knurled round nut or wing nut (M8)
- plastic or plywood base (10-20mm x 200 x 200mm)
- 2 sheets of plexiglass (3 x 200 x 200mm) -- for the camera stage (top) & specimen stage (middle)
- Lens from a cheap webcam (instructions for removing the lens can be found here)
- LED click light (often just bright daylight will work)
Carefully drill matching holes into the base, and both sheets of plexiglass in the positions shown in the diagram (for tips on how to do this you can follow the awesome instructions from the $10 smartphone microscope). Make an additional hole in the center of the plexiglass camera stage as shown, just big enough to fit your webcam lens. Fit it into the hole so that the end with the wider curved lens is flush with the top of the stage.
Assemble the parts of the stage as in the picture. The specimen stage is held down by an elastic band and can be raised or lowered to adjust focus by turning just the front knurled round nut (or, if you can't find one of those, a wing nut will do). The camera stage sits above the specimen stage and should remain fixed in position.
Step 2: Prepare and Image Your Cheek Cell Sample
Next you need to prepare your cheek cell sample. You can find instructions for doing this all over the internet (I didn't invent it). Methylene blue is a dye that was developed for use in the textile industry in the late 19th century, then later found to have medicinal properties and work well as a histological stain. You can easily find it in pet shops selling aquarium supplies where it is sold as a disinfectant and anti-fungal/-parasitic for treating sick fish. You should be able to find microscope slides and coverslips on ebay.
- clean cotton buds
- glass microscope slides
- glass coverslips
- methylene blue (diluted with water)
- pipette or dropper
Take a look at the video for an overview of how to prepare and image your cheek cell sample. More details can be found below.
- Use a cotton bud to scrape some cells from the inside of your cheek
- Smear the cells onto a microscope slide
- Gently lay a coverslip over the part of the slide you just smeared
- Add a drop or 2 of diluted methylene blue to one edge of the coverslip and let capillary action suck it underneath
- Turn on your smartphone's camera and position it on the camera stage over the webcam lens
- Put your slide on the specimen stage. Move it around and adjust the focus until you find some nice cells. The cytoplasm should be stained pale blue, the nucleii somewhat darker.
- TIP: Use a piece of folded white paper to reflect some light from the LED torch beneath your specimen (I find that shining the torch directly at the specimen is too bright).
Take a #cellfie!