Inkjet printing-assisted single-cell microarray on a hydrophobic surface chip for real-time monitoring of enzyme kinetics at single-cell level

A convenient, facile, and mask-free approach assay was developed for single-cell study by using a combination of inkjet printing technology and polydimethylsiloxane (PDMS) microchip-assisted processing. The inkjet printing technology resulted in 91% of the single-cell occupancy by individually spraying MCF-7 cells on a hydrophobic substrate and enabled the control over the number of cells with precision by strictly optimizing the printing parameters. Further, the microchip containing a cell chamber and straight channels was attached to the glass slide to explore the real-time performance of the cells. To address the performance attributes, the enzyme kinetics and various parameters of the post-printed MCF-7 cells, such as the levels of cell viability, reactive oxygen species (ROS), cell apoptosis, and proliferation, are monitored in real-time. Interestingly, high activity and proliferation, low level of ROS, and cell apoptosis demonstrated that the developed method provided a new way to the study of single-cell in-depth. Finally, ATP-induced cell proliferation of different cell number were analyzed, and the results would provide another perspective for the diagnosis and medical treatment.