Label-free leukocyte sorting and impedance-based profiling for diabetes testing

• Published in: Biosensors & bioelectronics Vol. 118; pp. 195 - 203
• Main Authors: Petchakup, Chayakorn, Tay, Hui Min, Yeap, Wei Hseun, Dalan, Rinkoo, Wong, Siew Cheng, Li, King Ho Holden, Hou, Han Wei
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 30.10.2018
• Subjects: biomarkers; Biosensing Techniques - instrumentation; Biosensing Techniques - methods; biosensors; C-reactive protein; Cell Separation; Dean flow fractionation; diabetes; Diabetes mellitus; Diabetes Mellitus, Type 2 - diagnosis; dielectric properties; Electric Impedance; electrodes; Humans; Impedance cytometry; inflammation; Leukocyte phenotyping; Leukocytes - cytology; lipids; lymphocytes; Microfluidics; monocytes; neutrophils; opacity; phenotype; risk factors; Leukocyte phenotyping; Impedance cytometry; Diabetes mellitus; Dean flow fractionation
• ISSN: 0956-5663; 1873-4235; 1873-4235
• DOI: 10.1016/j.bios.2018.07.052

Circulating leukocytes comprise of approximately 1% of all blood cells and efficient enrichment of these cells from whole blood is critical for understanding cellular heterogeneity and biological significance in health and diseases. In this work, we report a novel microfluidic strategy for rapid (< 1 h) label-free leukocyte sorting and impedance-based profiling to determine cell activation in type 2 diabetes mellitus (T2DM) using whole blood. Leukocytes were first size-fractionated into different subtypes (neutrophils, monocytes, lymphocytes) using an inertial spiral sorter prior to single-cell impedance measurement in a microfluidic device with coplanar electrode design. Significant changes in membrane dielectric properties (size and opacity) were detected between healthy and activated leukocytes (TNF-α/LPS stimulated), during monocyte differentiation and among different monocyte subsets (classical, intermediate, non-classical). As proof-of-concept for diabetes testing, neutrophil/monocyte dielectric properties in T2DM subjects (n = 8) were quantified which were associated with cardiovascular risk factors including lipid levels, C-reactive protein (CRP) and vascular functions (LnRHI) (P < 0.05) were observed. Overall, these results clearly showed that T2DM subjects have pro-inflammatory leukocyte phenotypes and suggest leukocyte impedance signature as a novel surrogate biomarker for inflammation. •A rapid and label-free leukocyte sorting and activation profiling strategy.•Enhanced impedance detection selectivity of sorted leukocyte subtypes.•Differential profiles for monocyte activation and differentiation.•Association of monocyte impedance with cardiovascular risk factors in diabetes.