Technology: Low-cost smartphone fluorescence microscope developed

A device that can convert a smartphone or tablet into a fluorescence microscope for less than US $50 is presented in a proof-of-principle study in Scientific Reports. The authors suggest that the device — which they have named a glowscope — could be used to image cells, tissues, and organisms under low magnification in schools, science outreach settings, and some research labs.

Fluorescence microscopes are used to study specimens labelled with fluorescent stains or expressing fluorescent proteins, such as those tagged with green fluorescent protein. However, as these microscopes usually cost at least several thousand US dollars, their use is typically limited to well-funded research labs.

The glowscope, devised by Jacob Hines and colleagues, is made of a plexiglass and plywood frame, a clip-on camera lens, an LED torch, and theatre stage lighting filters. The frame is used to position a smartphone or tablet above a specimen and the lens is clipped onto the phone or tablet camera to enable magnification. The specimen is illuminated by the LED torch and a lighting filter is placed over the lens to filter out unwanted wavelengths of light and allow visualisation of fluorescent light emitted by the specimen.

The authors demonstrated the abilities of the glowscope by using it to image live zebrafish embryos — which are between two and three millimetres long — expressing fluorescent proteins in either the spinal cord, cardiac tissue, or hindbrain. They found that the clip-on lens provided approximately five-fold magnification and was capable of imaging green and red fluorescent tissues with up to ten micrometre resolution — sufficient to view individual pigment cells. The authors used the glowscope to measure the heart rates of embryos and, after enhancing the clarity of videos recorded using free software, the movements of individual heart chambers.

As the materials for a glowscope cost between US $30 and $50, the authors propose that they could be used by school students to study anatomy, behaviour, physiology, development, and genetic inheritance in small organisms expressing fluorescent proteins, which could be obtained from laboratories. Several glowscopes and smartphones could also be used simultaneously to acquire video data in research labs that do not have access to multiple fluorescence microscopes, they add.

A complete description of the parts and instructions needed to assemble a glowscope is available in the supplementary information of the paper.