A Low Divergence 2940 nm Laser System for Mass Spectrometry Ionization Sources

描述（由申请人提供）：质谱法已成为了解分子如何在样品系统（如生物组织）中发挥作用的重要工具。大量的研发投资一直致力于质谱仪的技术进步。为了增加这些投资的价值，小企业开发了附加电离源，扩展了仪器的功能。这些第三方电离源使研究人员能够从组织样本中创建质谱图像（空间分子质量图），提高灵敏度，并直接分析样本，而无需真实的实时样本制备。 基质辅助激光解吸电离（MALDI）已成为许多第三方电离源的首选电离源，特别是用于MS成像（MSI），因为激光束可以聚焦到非常小的光斑尺寸以提高空间分辨率。典型地，激光器在UV中操作并且在光吸收基质的存在下解吸/电离样品。对基质添加的需要是一个限制因素，因为基质在样品表面上的均匀分布可能是耗时的、昂贵的、不可再现的，并且需要广泛的专业知识。已经证明，中红外激光可以通过使用水作为内源性基质成功地电离组织中的生物分子。直接中红外电离已成功地用于大气压（AP）MALDI源以及用于通过电喷雾电离（ESI）和真实的时间直接分析（DART）源的二次电离的有效解吸器。光学参量振荡器（OPO）已成为产生中红外光的首选激光技术。由于OPO光束的高发散度，将激光聚焦到非常小的光斑尺寸一直是一个问题。OPO的成本和尺寸阻碍了该技术的广泛采用。该资助计划旨在开发一种中红外OPO，其发散度尽可能接近第一阶段的衍射极限。将通过创建生物组织样本的高分辨率MS图像来测试OPO，几乎没有样本制备或预处理。第二阶段将解决成本和规模问题。 公共卫生相关性：这项拨款提案的资金将提供资源，以开发一种更好的工具，用于创建组织和细胞的“生物图像”。图像将显示重要分子的位置，如代谢物和蛋白质，在生物发育的不同阶段。这些信息将帮助科学家了解生命在其原生形式下的功能，或者当药物等外来物质被引入系统时。

DESCRIPTION (provided by applicant): Mass spectrometry has become an important tool for understanding how molecules function in sample systems such as biological tissue. Large R&D investments have been dedicated to the technological progress of mass spectrometers. To add value to these investments, small businesses have developed add-on ionization sources that extend the capabilities of the instrument. These third party ionization sources have enabled researchers to create mass spectrometry images (spatial molecular mass maps) from tissue samples, improve sensitivity and directly analyze samples without sample preparation in real time. Matrix-assisted laser desorption and ionization (MALDI) has become the ionization source of choice for many of these third-party ionization sources especially for MS imaging (MSI) because a laser beam can be focused to a very small spot size to increase spatial resolution. Typically, the laser operates in the UV and desorbs/ionizes the sample in the presence of a light absorbing matrix. The need for matrix addition is a limiting factor because the even distribution of the matrix across the sample surface can be time consuming, expensive, irreproducible and require extensive expertise. It has been demonstrated that mid-IR lasers can successfully ionized biomolecules in tissue by using water as an endogenous matrix. Direct mid-IR ionization has successfully been used in atmospheric pressure (AP) MALDI sources as well as an efficient desorber for secondary ionization by Electrospray Ionization (ESI) and Direct Analysis in Real Time (DART) sources. Optical parametric oscillators (OPO) have become the laser technology of choice for generating mid-IR light. Focusing the laser light to very small spot sizes has been a problem due to the high divergence of OPO beam. Cost and size of the OPOs prevent the technology from being widely adopted. This grant proposal aims to develop a mid-IR OPO with a divergence close as possible to the diffraction limit in Phase I. The OPO will be tested by creating highly resolved MS images of biological tissue samples will little to no sample preparation or pretreatment. Phase II will address cost and size issues. PUBLIC HEALTH RELEVANCE: Funding of this grant proposal will provide the resources to develop a better tool for creating a "biological image" of tissues and cells. The image will show the location of important molecules, such as metabolites and proteins, during different stages of biological development. This information will help scientists understand how life functions in its native form or when a foreign substance such as a drug is introduced into the system.