title: Integrating microfluidics and lensless imaging for point-of-care testing.
abstract: We demonstrate an integrated platform that merges a microfluidic chip with lensless imaging to target CD4(+) T-lymphocyte counts for HIV point-of-care testing at resource-limited settings. The chips were designed and fabricated simply with a laser cutter without using expensive cleanroom equipment. To capture CD4(+) T-lymphocytes from blood, anti-CD4 antibody was immobilized on only one side of the microfluidic chip. These captured cells were detected through an optically clear chip using a charge coupled device (CCD) sensor by lensless shadow imaging techniques. Gray scale image of the captured cells in a 24 mm x 4 mm x 50 microm microfluidic chip was obtained by the lensless imaging platform. The automatic cell counting software enumerated the captured cells in 3s. Captured cells were also imaged with a fluorescence microscope and manually counted to characterize functionality of the integrated platform. The integrated platform achieved 70.2+/-6.5% capture efficiency, 88.8+/-5.4% capture specificity for CD4(+) T-lymphocytes, 96+/-1.6% CCD efficiency, and 83.5+/-2.4% overall platform performance (n=9 devices) compared to the gold standard, i.e. flow cytometry count. The integrated system gives a CD4 count from blood within 10 min. 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.
authors.affiliation: Bio-Acoustic-MEMS in Medicine (BAMM) Laboratory, Center for Biomedical engineering, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: Sangjun
authors.initials: S
authors.lastname: Moon
authors.forename: Hasan Onur
authors.initials: HO
authors.lastname: Keles
authors.forename: Aydogan
authors.initials: A
authors.lastname: Ozcan
authors.forename: Ali
authors.initials: A
authors.lastname: Khademhosseini
authors.forename: Edward
authors.initials: E
authors.lastname: Haeggstrom
authors.forename: Daniel
authors.initials: D
authors.lastname: Kuritzkes
authors.forename: Utkan
authors.initials: U
authors.lastname: Demirci
mesh_terms: D018791:CD4 Lymphocyte Count / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000295:instrumentation*; D007909:Lenses; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D010363:Pattern Recognition, Automated / Q000379:methods*; D010783:Photometry / Q000295:instrumentation*; D019095:Point-of-Care Systems; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018511:Systems Integration