Flow cytometric analysis of the uptake of low-density lipoprotein by endothelial cells in microfluidic channels

Acceptance of microfluidic technology in everyday laboratory practice by biologists is still low. One of the reasons for this is that the technology combines poorly with standard cell biological and biochemical analysis tools. Flow cytometry is an example of a conventional analytical tool that is considered to be incompatible with microfluidic technology and its inherent small sample sizes. In this study, it is shown that properly designed microfluidic devices contain cell populations that are large enough to be analyzed by flow cytometry. To illustrate this, the uptake of fluorescent human low-density lipoprotein (LDL) by human endothelial cells that were cultured in a microfluidic channel was analyzed. It was found that the uptake of LDL by the cells increased linearly over time. Moreover, the uptake decreased when cells were pretreated with fluid shear stress inside the microfluidic devices. This study shows that microfluidic technology can be combined with conventional flow cytometry, while retaining the advantages of working with microfluidics such as low reagent use and dynamic cell culture conditions. This approach of combining microfluidic technology with conventional laboratory tools may contribute to greater acceptance of microfluidic devices in biological research.