Quantum dots-based immunofluorescent microfluidic chip for the analysis of glycan expression at single-cells.

Rich high-quality single-cell information from rare cell sample is very important for the quantitative systems biology description of cellular function. However, this type of data is often prohibited by the conventional analytical technology such as flow cytometry. In this paper, we described a microfluidic platform coupled with a quantum dots-based (QDs) immunofluorescence (IF) approach to measure the expression of glycans on the cell surface of single cells or cell population. Compared with conventional IF staining, the QDs-based IF probe exhibited higher brightness and stability against photobleaching. With the merits of the novel IF staining protocol and microfluidic platform, high-throughput IF staining was performed to measure the glycan expressions and the changes at single K562 cells after drug treatment. The protocol proposed here showed a high sensitivity on the glycan expression profile owing to the amplification of the signal in indirect IF staining. The size of cell sample was only 4 × 10(3) cells, which made the rare cell sample analysis accessible. This method may find widespread application for assessing cell-surface glycoprotein expression as well as analysis of the heterogeneity in cell populations in a high-throughput manner.