Development of Droplet Microfluidics Enabling Quantitative Measurements of Multiple Proteions at Single-Cell Level

This paper presents a microfluidic platform to measure three types of proteins of single cells where individual cells stained with fluorescence labelled antibodies were co-encapsulated with proteinase K, which stripped bound antibodies to generate even distributions of fluorescence within droplets. Based on the equivalent volume of the detection region formed by constriction microchannels, fluorescent measurements of droplets encapsulating single cells and pure antibody solutions were correlated with each other. Based on this approach, expressions of β-actin, α-tubulin and β-tubulin of CAL 27 cells were quantified as 1.15±0.53×10
⁶
, 2.43±1.39×10
⁵
and 2.29±0.98×10
⁵
(
$N$
cell
=2 869), providing a new perspective for single-cell analysis.