This paper describes a flexible microplasma jet device using a Tygon^® S-54-HL tube as a biocompatible tube and its potential in developing cancer therapies. The optical and physical properties of the plasma jets and preliminary apoptosis data of cultured murine tumor cells and nontumor fibroblast cells treated with these plasma jets are presented. Microplasma jets were observed to induce apoptosis in cultured murine cells in a dose-dependent manner. The murine melanoma tumor cells were more sensitive to plasma treatment than fibroblast cells. These features allow the direct and precise application of this microplasma jet device to tumor cells.

We report a high spatial resolution mass spectrometry (MS) system that allows us to image live hippocampal tissue slices under open-air atmospheric pressure (AP) and ambient temperature conditions at the subcellular level. The method is based on an efficient desorption process by femtosecond (fs) laser assisted with nanoparticles and a subsequent ionization step by applying nonthermal plasma, termed AP nanoparticle and plasma assisted laser desorption ionization (AP-nanoPALDI) MS method. Combining the AP-nanoPALDI with microscopic sample scanning, MS imaging with spatial resolution of 2.9 µm was obtained. The observed AP-nanoPALDI MS imaging clearly revealed the differences of molecular composition between the apical and basal dendrite regions of a hippocampal tissue. In addition, the AP-nanoPALDI MS imaging showed the decrease of cholesterol in hippocampus by treating with methyl β-cyclodextrin, which exemplifies the potential of AP-nanoPALDI for live tissue imaging for various biomedical applications without any chemical pretreatment and/or labeling process.