September 2, 2011
Portable Microscope Detects Bacteria Using Holograms
Engineers at UCLA have developed an inexpensive, portable, lensless microscope. This microscope may find its use in improving health care and sanitation in areas where sophisticated equipment is unavailable or unusable. The details of the microscope were published in the open-source journal Biomedical Optics Express.
BBC News reports that the microscope uses lasers and sophisticated mathematics, instead of lenses, to develop a holographic image that identifies bacteria or pathogens in food, water or even blood. These holographic images can then be uploaded into a computer for further analysis.
The device has two modes of operation. Transmission mode allows the device to scan larger volumes of blood or water, and reflection mode allows it to scan denser more opaque samples. According to Marketwatch, the spatial resolution of the device is less than two micrometers, comparable to bulkier microscopes with low- to medium-power lenses.
Dr. Karl Ryder of Leicester University´s Advanced Microscopy Center told BBC News, “Transmission mode is great for looking at optically transparent things like cells or very thin slices. However, if you want to look at more solid surfaces, you can´t use transmission mode, because the light wouldn´t get through.”
He then explained that in reflection mode, “You take a laser and you split the beam in two using a mirror. Then you use one of these beams to illuminate your sample. You can then recombine these two beams using clever mathematics to build a 3D image of your object.”
The miracle of the device is its light weight and low cost. The weight in the device is kept down by removing the lenses. The cost, around $100 according to BBC News, is maintained by using off the shelf components. The imaging components are the same ones used in iPhones or Blackberries, and cost less than $15 per chip. The laser light is the same as those found in laser pointer pens and costs less than $5. The whole system runs on AA batteries, according to a press release.
Aydogan Ozcan, an associate professor of electrical engineering and bioengineering at UCLA and senior author of the paper says the next step is commercializing the device. He has founded a company to develop the technology to healthcare professionals and hobbyists alike.
Ozcan said, “Global health is a big field that requires better diagnostic tools, because resource-poor countries don´t have the infrastructure for conducting essentially accurate diagnostic tests. There are so many problems that innovative solutions [like this microscope] would impact.”
Image Caption: This photograph shows the microscope in transmission mode. In this mode, the holographic microscope has a wider field of view than in reflection mode. While in this orientation, the device can be used to search for pathogens in large volumes of see-through materials, such as blood or water. (Photo: Ozcan BioPhotonics Group at UCLA/Biomedical Optics Express)
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