Leukocyte counting from a small amount of whole blood using a size‐controlled microcavity array

Abstract

Absolute counting of total leukocytes or specific subsets within small amounts of whole blood is difficult due to a lack of techniques that enable separation of all leukocytes from limited amounts of whole blood. In this study, a microfluidic device equipped with a size-controlled microcavity array for highly efficient separation of leukocytes from submicroliters of whole blood was developed. The microcavity array can separate leukocytes from whole blood based on differences in the size and deformability between leukocytes and other blood cells. Leukocytes recovered on aligned microcavities were continuously processed for image-based immunophenotypic analysis. Our device successfully recovered over 90% of leukocytes in 1 µL of whole blood without pretreatment such as density gradient centrifugation or erythrocyte lysis. In addition, the proposed system successfully performed absolute enumeration of human CD4(+) and CD8(+) leukocytes from 1 µL of whole blood, and the obtained data showed good correlation with conventional flow cytometric analysis. Our microfluidic device has great potential as a tool for a point-of-care leukocyte analysis system.

Oil Accumulation by the Oleaginous Diatom Fistulifera solaris as Revealed by the Genome and Transcriptome

“…The device was microfabricated as described (Hosokawa et al, 2009(Hosokawa et al, , 2012. In brief, a poly(ethylene terephthalate) plate (20 3 20 mm, thickness = 38 µm) was used as the substrate.…”

Deformability based Cell Sorting using Microfluidic Ratchets Enabling Phenotypic Separation of Leukocytes Directly from Whole Blood

“…Since RBCs can deform through openings (1–2 µm) much smaller than their diameter (~8 µm), while circulating leukocytes are spherical with diameters 6–8 μm 22 , microfilters consisting of pillars 23, 24 , weirs 23, 25, 26 , and membrane pores 23, 27 have been developed to separate these leukocytes from RBCs. A key limitation in directly processing whole blood using microfiltration is the potential for cells to clog and foul the filter microstructures.…”

Simple and rapid CD4 testing based on large-field imaging system composed of microcavity array and two-dimensional photosensor

“…Diluted blood samples (200 μL containing 1 μL of whole blood) were applied to the microcavity array at the flow rate of 200 μL/min. Under these conditions, 97.17 4.7% of leukocytes were recovered on the surface of the microcavity array (Hosokawa et al, 2012). Light with a wavelength of 464.5-499.5 nm was used for cell imaging.…”

“…Our research group has demonstrated a novel microfluidic device equipped with a size-controlled microcavity array for CD4 testing (Hosokawa et al, 2012(Hosokawa et al, , 2013. The microcavity array can separate leukocytes from a few microliters of whole blood as small as those obtained by a finger prick based on differences in the size of leukocytes and other blood cells.…”