抄録
Direct tissue analysis and ion imaging using mass spectrometry extract significant information directly from complex biological samples. In this paper, we introduce a method for the direct analysis of cultured cells. To analyze cultured cells by direct mass spectrometry (MS), we incubated HEK293T cells directly on an indium-tin-oxide layer on polyethylene terephthalate film. After fixation of cells on the film, matrix application was performed by spray-droplet method, which is a two-step matrix application method to improve the ionization efficiency of biological tissue samples. By direct MS of HEK293T cells, we obtained mass spectra of approximately 350 protein signals with good quality. Furthermore, we profiled proteins as digested products and identified major signals by applying an on-tissue digestion direct MS/MS method, which is the procedure for enzymatic protein digestion of biological tissue samples. This new approach enables proteomic analysis directly from the cell culture system.
