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. 2014 Feb 26;9(2):e89712.
doi: 10.1371/journal.pone.0089712. eCollection 2014.

Imaging and identification of waterborne parasites using a chip-scale microscope

Seung Ah Lee  1 , Jessey Erath  2 , Guoan Zheng  3 , Xiaoze Ou  1 , Phil Willems  4 , Daniel Eichinger  2 , Ana Rodriguez  2 , Changhuei Yang  5
Affiliations

Imaging and identification of waterborne parasites using a chip-scale microscope

Seung Ah Lee et al. PLoS One. .

Abstract

We demonstrate a compact portable imaging system for the detection of waterborne parasites in resource-limited settings. The previously demonstrated sub-pixel sweeping microscopy (SPSM) technique is a lens-less imaging scheme that can achieve high-resolution (<1 µm) bright-field imaging over a large field-of-view (5.7 mm×4.3 mm). A chip-scale microscope system, based on the SPSM technique, can be used for automated and high-throughput imaging of protozoan parasite cysts for the effective diagnosis of waterborne enteric parasite infection. We successfully imaged and identified three major types of enteric parasite cysts, Giardia, Cryptosporidium, and Entamoeba, which can be found in fecal samples from infected patients. We believe that this compact imaging system can serve well as a diagnostic device in challenging environments, such as rural settings or emergency outbreaks.

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Conflict of interest statement

Competing Interests: Guoan Zheng is the ePetri Inc. company President, and owns shares in ePetri Inc. Phil Willems is the ePetri Inc. company CEO, and owns shares in ePetri Inc. Changhuei Yang is the company founder and owns shares in ePetri Inc., and is also a paid consultant for ePetri Inc. Seung Ah Lee, Xiaoze Ou and the California Institute of Technology own shares in ePetri Inc. Some of the work described in this paper is covered by patent applications owned and filed by the California Institute of Technology and licensed to ePetri Inc. Authors Yang, Zheng, Lee and Willems, as named inventors on said patent applications, may receive royalty payments relating to such licensing, pursuant to Caltech’s patent policy. Patent details are as follows: E-Petri Dishes, Devices, and Systems Inventors: Zheng, Guoan; Yang, Samuel; Yang, Changhuei; Lee, Seung Ah; Pang, Shuo Serial number : 13/411,302 Status : Filed, Licensed. E-Petri Dishes, Devices, and Systems Inventors: Zheng, Guoan; Lee, Seung Ah; Yang, Changhuei; Yang, Samuel; Judkewitz, Benjamin; Pang, Shuo; Wu, Jigang Serial number: 201280003668.0 Status: Filed, Licensed. E-Petri Dishes, Devices, and Systems Inventors: Zheng, Guoan; Lee, Seung Ah; Yang, Changhuei; Yang, Samuel; Pang, Shuo Serial Number: 12752493.2 Status: Filed, Licensed. Self-Imaging Petri Dish for Microscopic Viral Plaque Assay Inventors: Willems, Phil; Zheng, Guoan; Judkewitz, Benjamin; Han, Chao; Yang, Changhuei Serial Number: 61/738,931 Status: Filed, Licensed. There are no further patents, products in development or marketed products to declare. This does not alter the authors' adherence to all the PLOS ONE policies on sharing data and materials, as detailed online in the guide for authors.

Figures

Figure 1
Figure 1. (a) Lens-less SPSM imaging system prototype.
(b) A CMOS image sensor with a microfluidic chamber mounted on the sensor surface for sample loading. (c) A sample slide can be made directly on the image sensor.
Figure 2
Figure 2. Schematic of the working principle of SPSM color imaging.
(a) While the target objects rest on the surface of the image sensor, we sequentially turn on each LED in the RGB LED array illumination above and take sequences of low-resolution images. (b) Each low-resolution sequence is reconstructed into three monochromatic high-resolution images using the pixel super-resolution algorithm. The red, green, and blue channels are then combined into a single color image.
Figure 3
Figure 3. Full field-of-view (5.7 mm×4.3 mm) of E. invadens cysts with iodine staining.
The inset shows a part of the reconstructed image.
Figure 4
Figure 4. SPSM and 20× objective microscope images of Giardia, Cryptosporidium, and Entamoeba cysts.
We imaged unstained cysts, iodine-stained, and methylene blue-stained cysts.
Figure 5
Figure 5. Digitally refocused images of parasite cysts.
Entamoeba (blue), giardia (red), and cryptosporidium (black) can be found in different z-planes.
See this image and copyright information in PMC

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