Surface-printed microdot array chips coupled with matrix-assisted laser desorption/ionization mass spectrometry for high-throughput single-cell patterning and phospholipid analysis

RATIONALE: Single-cell analysis is very important in several research fields for the heterogeneity of individual cells, which has been well accepted. However, restricted by the size and low content of a single cell, current studies have encountered challenges in high-throughput, high-space resolution and sensitivity, and multicomponent analysis. A methodology of a surface-printed microdot array chip coupled with matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) is presented in this study for high-throughput single-cell patterning and phospholipid analysis. METHODS: The poly-L-lysine (PLL) used as ink molecule was printed on an oxygen plasma processed indium tin oxide (ITO)-coated glass slide to form a microdot array by micro-contact printing technology. The cell array was then formed on the PLL microarray through electrostatic adsorption force. 9-Aminoacridine (9-AA) matrix was applied on the cell array before it was analyzed by MALDI-TOF MS. MALDI mass spectrometry imaging (MALDI-MSI) was then used for high-throughput, quick measurement, and multicomponent analysis of the cell array. RESULTS: The single-cell capture efficiency of the cell array formed on the PLL microarray was about 40%. Twelve phospholipids were detected at the single-cell level, and the structures were further confirmed by MS/MS. The MALDI-MSI of selected ions showed a conformity with the cell array. The relative signal intensity data of selected ions were extracted from every pixel in the image within several minutes. The heterogeneity between individual cells was revealed from the relative signal intensity of phospholipids in 1-3 cells. CONCLUSIONS: Compared to the existing related approaches, high-throughput, quick measurement, and multicomponent single-cell analysis have been realized by our method. Through different ink molecules used for micro-contact printing, the established platform could have the potential to capture and analyze specific cells. Copyright (C) 2016 John Wiley & Sons, Ltd.