Lens-free holographic microscopy for complete blood analysis on a chip

Complete Blood Count (CBC) is a routine blood test program that is often prescribed by physicians. It analyzes the values of various blood cells and can be used for detection of related diseases and infections. Flow cytometry has been one of the widely used technique to count, characterize and classify blood cells in the previous studies. However, the technique suffers from time-consuming procedure for analyzing the target cell and the bulky design of the detection platform. Hence, we propose a high-throughput lensless holographic microscopy for rapid blood analysis and imaging in large field-of-view (FOV) of 30 mm2. The holographic technique can simultaneously record the amplitude and phase of the diffraction pattern, which are different due to cell sizes and materials for further cell counting. Then the original cell images are digitally reconstructed by scalar diffraction theory and inverse Fourier transform to identify red blood cells, white blood cells and platelets. The lens-free holographic platform has compact size that makes it easy-to-handle. The lens-free design is able to analyze the blood samples on a chip by using the spatial coherence light (LED) emanating from a pinhole, and imaging on the CMOS sensor with a spatial resolution of 1.67 μm. The application of a CBC can diagnose anemia, infections, and other disorders. We believe that the lensless on-chip holographic platform will be a cost-effective tool for point-of-care cytometry.