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The cell has a three-dimensional (3D) structure and its spatial arrangement is often very important to molecular mechanisms essential for life. In order to visualize 3D morphologies of cells, confocal laser imaging was developed. 1 The method is, however, only applicable to fluorescence-probed molecules, 2 which limits the observable number of molecules, and such artificial probing sometime perturbs normal molecular mechanisms. Cotte et al. applied holographic and tomographic irradiation to microscopy and finally innovated a threedimensional computed holographic and tomographic (HT) laser microscope. 3 The laser beam that penetrates the cell at an angle experiences a delay in the phase of its beam, which is magnified and overlayed with reference beam to make a holographic image. The holograms at various angles then deconvoluted by tomographic algorithms to create a precise 3D cell image. The 3D-HT microscope can visualize 3D morphological aspects by contrasting refractive indexes observed by the laser monochromatic wavelength, making staining unnecessary.We have developed live single-cell mass spectrometry, 4-7 in which the contents of a single cell, usually picoliter level or less, are sucked by a nanospray tip (a sort of glass capillary needle) and fed directly into a mass spectrometer after the addition of an ionization solvent to the rear end of the tip. In this method, the exact amount sucked is unclear because it is such a tiny volume. Furthermore, 3D spatial location and identity of the contents are also ambiguous. Through the combination of these two techniques, 3D-HT microscopy and live single-cell mass spectrometry, greater 3D spatial resolution (X-Y-axis 0.18 μm and Z-axis 0.33 μm) and improved quantitative single-cell analysis is expected. The first trial of this combination and its results are documented in this paper, and we think nextgeneration live single-cell mass spectrometry is quite promising.Human hepatocellular carcinoma cell line (HepG2) was cultured in Dulbecco's modified Eagle medium in addition to 10% fetal calf serum (FBS), 100 mg/mL penicillin, and 100 mg/mL streptomycin G in 35 mm glass bottom dishes at 37 C and 5% CO2. HepG2 cells were positioned under the HT laser microscope, and the HT scan took 2 s to acquire one 3D image. Figure 1 shows the schematic principle of the HT laser microscope (3D Cell Explorer, Nanolive, SA, Switzerland). Fig. 1 Schematic of live single-cell mass spectrometry with quantitation by holographic and tomographic laser microscopy. The laser beam is split into a reference beam (going down to the CCD camera) and an observation beam that irradiates the cell at 45 degree angle. A micromanipulator was setup next to microscope to allow precise suction with a nanospray tip. The sucked cellular matter was then blasted through the mass spectrometer.

The dynamics of a cell is always changing. Cells move, divide, communicate, adapt, and are always reacting to their surroundings non-synchronously. Currently, single-cell metabolomics has become the leading field in understanding the phenotypical variations between them, but sample volumes, low analyte concentrations, and validating gentle sample techniques have proven great barriers toward achieving accurate and complete metabolomics profiling. Certainly, advanced technologies such as nanodevices and microfluidic arrays are making great progress, and analytical techniques, such as matrix-assisted laser desorption ionization (MALDI), are gaining popularity with high-throughput methodology. Nevertheless, live single-cell mass spectrometry (LCSMS) values the sample quality and precision, turning once theoretical speculation into present-day applications in a variety of fields, including those of medicine, pharmaceutical, and agricultural industries. While there is still room for much improvement, it is clear that the metabolomics field is progressing toward analysis and discoveries at the single-cell level.

A supramolecular complex of syn-(methyl,methyl)bimane (1) and β-cyclodextrin demonstrates a sensitive (limit of detection = 0.60 nM) and selective fluorescence turn-off response in the presence of cobalt in aqueous media,...

The incidence of cancer is increasing worldwide as well as in the United Arab Emirates (UAE). Currently, researchers are advocating not only for prevention programs but also for early detection. In this study, we aimed to assess the general awareness of cancer among the UAE population, with a focus on environmental risk factors. A descriptive cross-sectional design was employed, and a structured questionnaire was used to collect data from 385 participants. A total of 91.2% of the study population identified cancer as the leading cause of death, while 64.6% of the subjects were able to identify the key causes of cancer. A total of 87.3% and 70.5% of the participants were able to define tobacco and alcohol, respectively, as cancer-causing agents. Most of the study population failed to identify cancer-related infectious agents and incense smoke as carcinogens. Respondents in the medical professions had the highest knowledge score when compared with respondents with a non-medical profession and unemployed participants (p < 0.0005). To fill the gaps in cancer-related knowledge, participants were asked about their preferred method for cancer education, and 83.9% of the participants favored the media as a source of information. Conclusively, our findings indicated a gap in cancer knowledge among UAE residents, which highlights the importance of educational campaigns by health authorities; a follow-up study evaluating the success of educational campaigns is also warranted.