Parallel probing of drug uptake of single cancer cells on a microfluidic device.

Drug resistance is frequently developing during treatment of cancer patients. Intracellular drug uptake is one of the important characteristics to understand mechanism of drug resistance. However, the heterogeneity of cancer cells requires the investigation of drug uptake at the single cell level. Here, we developed a microfluidic device for parallel probing of drug uptake. We combined a v-type valve and peristaltic pumping to select individual cells from a pool of prostate cancer cells (PC3) and place them successively in separate cell chambers in which they were exposed to the drug. Six different concentrations of doxorubicin, a naturally fluorescent anti-cancer drug, were created in loop-shaped reactors and exposed to the cell in closed 2 nL volume chambers. Monitoring every single cell over time in 18 parallel chambers revealed increased intracellular fluorescence intensity according to the dose of doxorubicin, as well as nuclear localization of the fluorescent drug after 2 h of incubation. The herein proposed technology demonstrated a first series of proof of concept experiments and it shows high potential to use for probing drug sensitivity of single cancer cell.