Computational and Systems Medicine, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, Sir Alexander Fleming Building, South Kensington, London, SW7 2AZ, UK.
NiCE-MSI, National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UK.
J Am Soc Mass Spectrom. 2017 Oct;28(10):2090-2098. doi: 10.1007/s13361-017-1714-z. Epub 2017 Jun 15.
A new, more robust sprayer for desorption electrospray ionization (DESI) mass spectrometry imaging is presented. The main source of variability in DESI is thought to be the uncontrolled variability of various geometric parameters of the sprayer, primarily the position of the solvent capillary, or more specifically, its positioning within the gas capillary or nozzle. If the solvent capillary is off-center, the sprayer becomes asymmetrical, making the geometry difficult to control and compromising reproducibility. If the stiffness, tip quality, and positioning of the capillary are improved, sprayer reproducibility can be improved by an order of magnitude. The quality of the improved sprayer and its potential for high spatial resolution imaging are demonstrated on human colorectal tissue samples by acquisition of images at pixel sizes of 100, 50, and 20 μm, which corresponds to a lateral resolution of 40-60 μm, similar to the best values published in the literature. The high sensitivity of the sprayer also allows combination with a fast scanning quadrupole time-of-flight mass spectrometer. This provides up to 30 times faster DESI acquisition, reducing the overall acquisition time for a 10 mm × 10 mm rat brain sample to approximately 1 h. Although some spectral information is lost with increasing analysis speed, the resulting data can still be used to classify tissue types on the basis of a previously constructed model. This is particularly interesting for clinical applications, where fast, reliable diagnosis is required. Graphical Abstract ᅟ.
一种新的、更强大的解吸电喷雾电离（DESI）质谱成像喷雾器被提出。DESI 的主要变异性来源被认为是喷雾器各种几何参数的不可控变异性，主要是溶剂毛细管的位置，或者更具体地说，是其在气体毛细管或喷嘴内的定位。如果溶剂毛细管不在中心，喷雾器就会变得不对称，使得几何形状难以控制，从而影响重现性。如果改善毛细管的刚度、尖端质量和定位，则可以将喷雾器的重现性提高一个数量级。通过在像素尺寸为 100、50 和 20 μm 下获取图像，在人结直肠组织样本上展示了改进后的喷雾器的质量及其用于高空间分辨率成像的潜力，这对应于 40-60 μm 的横向分辨率，类似于文献中公布的最佳值。喷雾器的高灵敏度还允许与快速扫描四极杆飞行时间质谱仪结合使用。这提供了高达 30 倍的 DESI 采集速度，将 10mm×10mm 大鼠脑样本的总采集时间缩短到大约 1 小时。尽管随着分析速度的增加会丢失一些光谱信息，但仍然可以使用这些数据根据之前构建的模型对组织类型进行分类。这对于临床应用特别有趣，因为需要快速、可靠的诊断。
