Real-time monitoring the efficacy of 7-hydroxycoumarin to cells cultured on microfluidics in different extracellular pH environments by chip-mass spectrometry.

The extracellular microenvironments play a key role in tumor metabolism. To online dynamic monitoring the efficacy of 7-hydroxycoumarin (7-OHC) to cells cultured on microfluidics in acidic microenvironment, we developed an integrated multi-channel chip-mass spectrometry system. This system has six drug-loading units, cell culture chamber, metabolite collection, filtration, HPLC separation and MS detection. The cells in each microchannel will be incubated with continuous flow of culture medium, metabolites will be collected by the fixed card slot, automatic sampling needle will be precise positioned and sampled. Through this new system, the 7-hydroxycoumarin-sulfonate (7-OHC-sulfonate) and 7-hydroxycoumarin-glucuronide (7-OHC-glucuronide) can be determined in real-time. The results revealed that the addition of lactic acid promoted the formation of inactive 7-OHC-sulfonate and 7-OHC-glucuronide metabolites. Besides, acidic extracellular environment amplified cancer cell proliferation, indicating the anticancer effect of 7-OHC was weakened by low extracellular pH.