Phone camera becomes mini-microscope for diagnostics

Microscopy is relatively easy to perform and at low cost, which makes it a universal diagnostic method for most globally important parasitic infections. But many methods are limited to well-equipped laboratories and are difficult to maintain at the basic levels of health care due to lack of resources and adequately trained personnel.

Researchers at the Institute for Molecular Medicine Finland (FIMM) at the University of Helsinki and at the Karolinska Institute in Sweden recently showed that new techniques for high-resolution imaging and image transfer over data networks may be utilized to solve these diagnostic problems.

A test sample is placed directly on the exposed surface of the image sensor chip after removal of the optics. The resolution of such mini-microscopes is dependent on the pixel size of the sensor, but sufficient for identification of several pathogenic parasites. Photo by Heli Vilmi; courtesy of Johan Lundin Lab.

A team led by Dr. Johan Lundin of FIMM and Dr. Ewert Linder of the Karolinska Institute modified inexpensive imaging devices – €10 webcams and mobile phone cameras – to turn them into mini-microscopes. They placed test samples directly on the exposed surface of the image sensor chip after removal of the optics. The resolution of the devices depended on the sensor’s pixel size but was sufficient to identify several pathogenic parasites.

In their study, published in PLOS Neglected Tropical Diseases (doi: 10.1371/journal.pntd.0002547), the researchers used the mini-microscopes they constructed to yield images of parasitic worm eggs present in urine and stools of infected individuals. They first used this novel approach to detect urinary schistosomiasis, a severely underdiagnosed infection affecting hundreds of millions, primarily in sub-Saharan Africa. For point-of-care diagnostics, they developed a highly specific pattern-recognition algorithm to analyze the image from the mini-microscope and automatically detect parasite eggs.

“The results can be exploited for constructing simple imaging devices for low-cost diagnostics of urogenital schistosomiasis and other neglected tropical infectious diseases,” Lundin said. “With the proliferation of mobile phones, data transfer networks and digital microscopy applications, the stage is set for alternatives to conventional microscopy in endemic areas.”