A Constriction Channel Based Microfluidic Flow Cytometry Enabling High-Throughput Quantification of Multiple Types of Intracellular Proteins in Single Cells

This paper presents a constriction channel based microfluidic flow cytometry enabling high-throughput quantification of multiple types of intracellular proteins in single cells. Cells stained with fluorescent labelled antibodies were aspirated into the constriction channel with excited fluorescent signals detected and translated into copy numbers of proteins based on calibration curves formed by flushing gradient solutions of fluorescent labeled antibodies into constriction channels. As a demonstration, single-cell β-actins and α-tubulins were quantified as 1.51±1.00×10⁶ and 2.19±2.08×10⁵ (A549, N_cell =1707), 8.02±5.49×10⁵ and 2.97±3.15×10⁵ (Hep G2, N_cell =2625), and 6.40±4.68×10⁵ and 0.73±0.69×10⁵ (PC3, N_cell=1794), respectively. Cell-type classification rates increased from 71.5±4.7% (β-actin) and 74.8±9.0% (α-tubulin) to 84.9±5.3% (β-actin+α-tubulin), confirming the effectiveness of this approach.