Integrating microfluidics and lensless imaging for point-of-care testing

An integrated platform that merges a microfluidic chip with lens-less imaging to target CD4⁺ T-lymphocyte counts for point-of-care testing at resource-limited settings. We demonstrate an integrated platform that merges a microfluidic chip with lens-less imaging to target CD4⁺ T-lymphocyte counts for point-of-care testing at resource-limited settings. The chips were designed and fabricated simply with a laser cutter instead of using expensive cleanroom equipment. To capture CD4⁺ T lymphocytes, anti-CD4 antibody was immobilized on one side of the microfluidic chip. These captured cells were detected through an optically clear chip using a charge coupled device (CCD) sensor by lens-less shadow imaging techniques. Gray scale image of the captured cells in the 24 mm times 4 mm times 50 mum microfluidic chip was obtained by the platform. The automatic cell counting software enumerated the captured cells in three seconds. Captured cells were also imaged with a fluorescence microscope and manually counted to characterize functionality of the integrated platform. We achieved 70.2 plusmn 6.5% capturing efficiency, 88.8 plusmn 5.4% capturing specificity for CD4⁺ T-lymphocytes, 96 plusmn 1.6% CCD efficiency, and 83.5 plusmn 2.4% overall platform performance (n = 9 devices). The integrated platform points a promising direction for point-of-care testing (POCT) to rapidly capture, image and count subpopulations of cells from blood samples in an automated matter.