UCLA Professors Creates Smartphone Microscopes That Detects a Single Virus
Imagine your smartphone working like an industry-leading Zeiss microscope. Well, don’t think too long because it’s happening now. Aydogan Ozcan a UCLA professor of bioengineering and electrical engineering and Henry Samueli, school of engineering and Applied Science has created a portable attachment to be used with your smartphone. These sophisticated devices has the ability to test for bacteria and viruses, weigh less than half a pound. This cellphone-based imagining device can be used for specific and sensitive detection of sub-wavelength objects such as bacteria, allowing the nanotechnology door to be opened in remote and resource-limited environments.
“This cellphone-based imaging platform could be used for specific and sensitive detection of sub-wavelength objects, including bacteria and viruses and consequently, could enable the practice of nanotechnology and biomedical testing in field settings and even in isolated and resource-limited environments,” Ozcan says. “These results also constitute the first time that single nanoparticles and viruses have been detected using a cellphone-based, field-portable imaging system.”
The new research, published in the American Chemical Society’s journal ACS Nano, comes on the heels of Ozcan’s other recent creations, including a cellphone camera-enabled sensor for allergens in food products and a smartphone attachment that can conduct common kidney tests. Taking clear images of objects as tiny as a single virus or a nanoparticle is challenging because the optical signal strength and contrast are very low for objects that are smaller than the wavelength of light.
In the ACS Nano paper, Ozcan details a fluorescent microscope device fabricated by a 3-D printer that contains a color filter, an external lens, and a laser diode. The diode illuminates fluid or solid samples at a steep angle of roughly 75 degrees. This oblique illumination avoids the detection of scattered light that would otherwise inhibit with the intended fluorescent image. Using this device, which attaches directly to the camera module on a smartphone, Ozcan’s team was able to detect single human cytomegalovirus (HCMV) particles. HCMV is a common virus that can cause birth defects such as deafness and brain damage and can rush the death of adults who have received organ implants, who are infected with the HIV virus or whose immune systems otherwise have been weakened. A single HCMV particle measures about 150–300 nanometers; a human hair is roughly 100,000 nanometers thick.
In another experiment, Ozcan’s team also detected nanoparticles— specially marked fluorescent beads made of polystyrene— as small as 90 to 100 nanometers. To verify these results, researchers in Ozcan’s lab used other imaging devices, including a scanning electron microscope and a photon-counting confocal microscope. These experiments confirmed the findings made using the new cellphone-based imaging device.
Ozcan is the principal investigator on the research. The first author of ACS Nano the paper is Qingshan Wei, a postdoctoral researcher in Ozcan’s lab and at UCLA’s California NanoSystems Institute (CNSI), where Ozcan is associate director. Other co-authors include Hangfei Qi and Ting-Ting Wu of the UCLA Department of Molecular and Medical Pharmacology; Wei Luo, Derek Tseng, Zhe Wan and Zoltan Gorocs of the UCLA Electrical Engineering Department; So Jung Ki of the UCLA Department of Chemistry and Biochemistry; Laurent Bentolila of CNSI and the UCLA Department of Chemistry and Biochemistry; and Ren Sun of the UCLA Department of Molecular and Medical Pharmacology and CNSI.
