Pollen (left) and plant stems (middle, right) are shown from an expensive microscope (top) and with an inexpensive add-on lens for an iPhone (bottom). (Source: University of California, Davis)
Medical and scientific measurements of all types are done with optical microscopes, which snap photos of blood samples that are then evaluated by screening technicians who refer suspect images to full-fledged doctors.
Researchers at University of California (Davis) have demonstrated an under-$50 close-up lens for the iPhone that can do the same thing--namely screen photos of blood samples, then refer suspect images to remotely located doctors using its 3G Internet connection. The team’s proposed add-on for the iPhone will be described in detail this month at the Optical Society of America's (OSA) Annual Meeting called "Frontiers in Optics (FiO) 2011" (San Jose, Calif. Oct. 16-20, 2011).
With all the sophisticated medical diagnosis techniques available today, optical microscopes are still the workhorse technology, with sales of over $3 billion in 2011 and growing at a rate of about five percent, according to BCC Research LLC. The group predicts the optical microscope market will exceed $4 billion by 2016.
Pollen (left) and plant stems (middle, right) are shown from an expensive microscope (top) and with an inexpensive add-on lens for an iPhone (bottom). (Source: University of California, Davis)
Today microscopy depends on "micron range" optical photography of blood and other patient samples, which can be achieved with a humble iPhone, according to Sebastian Wachsmann-Hogiu, a physicist with UC Davis' Department of Pathology and Laboratory Medicine at the Center for Biophotonics, Science and Technology. The 1.7 micron pixel size of the iPhone's camera combined with an inexpensive 5X magnification lens, gives the iPhone a microscope function in just the micron-range resolution needed to diagnose patient samples.
For developing nations an add-on microscope to smartphones could enable them to send in photos of patient samples for doctors to remotely diagnose. In fact, there are other smartphones with integrated microscopes and medical diagnostic apps, such as the LifeLens project to identify malaria in the field with a Window-based smartphone microscope. But the UC Davis team's aim was to demonstrate how inexpensively a bare-bones system could be made.
The first generation prototype was set up to not need any additional hardware at all--just a drop of water atop the iPhone camera lens which magnified the images as well as the ball lens that was finally chosen for the team's prototype.
"The water formed a meniscus, and its curved surface acted like a magnifying lens," said Wachsmann-Hogiu. "It worked fine, but the water evaporated too fast."
A one-millimeter ground glass ball lens--an under-$50 sphere that acts as magnifying glass--was used in the prototype constructed by Kaiqin Chu, a post-doctoral researcher at UC Davis. The ball lens was mounted in rubber surround that was fitted over the iPhone’s own camera lens.
The images were not as high-resolution as the laboratory microscope, but the doctors at the UC Davis Medical Center were still able to diagnose blood by counting cells and by noting the shapes of cells, such as in the banana-shape typical of sickle cell anemia.
Next the team wants to improve its lens resolution further, for making diagnoses of other samples such as skin, as well as develop apps for automatic screening, such as counting the number of red- and white-blood cells in a sample. They are also developing an inexpensive spectrometer add-on that could potentially identify the chemical signatures of substances by their spectra, such as reading out how much oxygen is in a patient's blood.
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