High-throughput screening of large volumes of whole blood using structured illumination and fluorescent on-chip imaging

Electrical Engineering Department, University of California, Los Angeles, CA 90095, USA. .
Lab on a Chip (Impact Factor: 6.12). 10/2012; 12(23). DOI: 10.1039/c2lc40894e
Source: PubMed


Undiluted blood samples are difficult to image in large volumes since blood constitutes a highly absorbing and scattering medium. As a result of this limitation, optical imaging of rare cells (e.g., circulating tumour cells) within unprocessed whole blood remains a challenge, demanding the use of special microfluidic technologies. Here we demonstrate a new fluorescent on-chip imaging modality that can rapidly screen large volumes of absorbing and scattering media, such as undiluted whole blood samples, for detection of fluorescent micro-objects at low concentrations (for example ≤50-100 particles/mL). In this high-throughput imaging modality, a large area microfluidic device (e.g., 7-18 cm(2)), which contains for example ∼0.3-0.7 mL of undiluted whole blood sample, is directly positioned onto a wide-field opto-electronic sensor-array such that the fluorescent emission within the microchannel can be detected without the use of any imaging lenses. This microfluidic device is then illuminated and laterally scanned with an array of Gaussian excitation spots, which is generated through a spatial light modulator. For each scanning position of this excitation array, a lensfree fluorescent image of the blood sample is captured using the opto-electronic sensor-array, resulting in a sequence of images (e.g., 144 lensfree frames captured in ∼36 s) for the same sample chip. Digitally merging these lensfree fluorescent images based on a maximum intensity projection (MIP) algorithm enabled us to significantly boost the signal-to-noise ratio (SNR) and contrast of the fluorescent micro-objects within whole blood, which normally remain undetected (i.e., hidden) using conventional uniform excitation schemes, involving plane wave illumination. This high-throughput on-chip imaging platform based on structured excitation could be useful for rare cell research by enabling rapid screening of large volume microfluidic devices that process whole blood and other optically dense media.

Download full-text


Available from: Ahmet F Coskun,
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Here we report a low-cost and simple wide field-of-view (FOV) on-chip fluorescence-imaging platform, termed fluorescence Talbot microscopy (FTM), which utilizes the Talbot self-imaging effect to enable efficient fluorescence imaging over a large and directly scalable FOV. The FTM prototype has a resolution of 1.2 μm and an FOV of 3.9  mm×3.5  mm. We demonstrate the imaging capability of FTM on fluorescently labeled breast cancer cells (SK-BR-3) and human embryonic kidney 293 (HEK) cells expressing green fluorescent protein.
    Optics Letters 12/2012; 37(23):5018-20. DOI:10.1364/OL.37.005018 · 3.29 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Time-lapse or longitudinal fluorescence microscopy is broadly used in cell biology. However, current available time-lapse fluorescence microscopy systems are bulky and costly. The limited field-of-view (FOV) associated with microscope objective necessitates mechanical scanning if a larger FOV is required. Here we demonstrate a wide FOV time-lapse fluorescence self-imaging Petri dish system, termed the Talbot Fluorescence ePetri, which addresses these issues. This system's imaging is accomplished through the use of the Fluorescence Talbot Microscopy (FTM). By incorporating a microfluidic perfusion sub-system onto the platform, we can image cell cultures directly from within an incubator. Our prototype has a resolution limit of 1.2 μm and an FOV of 13 mm(2). As demonstration, we obtained time-lapse images of HeLa cells expressing H2B-eGFP. We also employed the system to analyze the cells' dynamic response to an anticancer drug, camptothecin (CPT). This method can provide a compact and simple solution for automated fluorescence imaging of cell cultures in incubators.
    Analytical Chemistry 01/2013; 85(4). DOI:10.1021/ac303356v · 5.64 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We review our progress on the development of computational lensfree on-chip microscopy and tomography techniques for biomedical imaging, microanalysis and telemedicine applications.
    SPIE Optical Metrology 2013; 05/2013
Show more