IDBR: TYPE A Ultrahigh Spatial Resolution Sub-organelle Molecular Mass Spectrometry Imaging Using Liquid Metal Ion Beam Desorption and Radiofrequency Ionization

贝勒大学获得了开发超高空间分辨率质谱成像（MSI）仪器的奖项。这项研究的潜在影响是深远的，因为目前还没有技术可以解决高空间分辨率MSI的现有缺点。这项最先进技术的直接受益者将包括学生、研究人员和整个社会。这项工作预计将为各种技术转让机会和潜在的工业合作打开大门，与大学进行大规模生产，将产生显著的经济和社会效益。将从贝勒大学外展项目的代表性不足的群体中招募两名合格的本科生，以获得高质量的研究经验。此外，两名研究生和一名科学家将在MSI接受研究活动和专业知识的培训，以扩大他们的科学知识。项目中所有学员的研究成果和报告将在年度高级仪器研讨会上重点介绍，该研讨会针对来自历史上黑人学院和大学以及德克萨斯州和附近州的西班牙裔服务机构的本科生和教师导师。虚拟科学网络将用于传播研究成果和促进新的合作。这些NSF支持的活动将用于扩大未被充分代表的学生群体参与未来的生物MSI研究。这项研究将允许建造一个尖端的分子成像仪器，该仪器将被贝勒大学的教师和学生使用，并用于教授高级仪器课程和促进机构间的合作。这项研究的成果将通过出版物和会议报告进行传播，以促进新的超高空间分辨率MSI的更广泛使用。质谱成像（MSI）提供了表面形态的信息，但也产生了不同样品组分的特定分子特性的高度期望的细节。在传统的MSI中，主激光或解吸光束在样品表面光栅解吸，随后分析生物组织的不同成分，以构建三维图像。因此，MSI中的空间分辨率受到解吸光束的尺寸（或激光足迹）和从表面解吸足够数量的底物分子以进行后续电离和质量分析所需的能量阈值的限制。此外，低电离效率会严重限制灵敏度和空间分辨率（通常为几微米），以表征细胞成分。本研究的目的是在分子水平上为细胞器的高度特异性和敏感性表征提供新的分析能力。该项目将通过将聚焦离子束（FIB）中性解吸与新发现的高效射频电离（RFI）相结合，在MSI领域开创一个新的前沿。亚细胞MSI的持续挑战包括实现足够的检测灵敏度，克服电离偏置，在分析过程中最大限度地减少底物成分的潜在迁移，以及提高空间分辨率。当前的MSI策略通常以牺牲另一个挑战为代价来解决其中一个挑战。为了改善目前MSI的权衡，RFI源的几何结构将被优化，以电离比目前可能的更大比例的解吸中性羽流。RFI无与伦比的灵敏度有望降低液态金属离子源（LMIS）的主光束功率要求，从而使x-y（表面）和z（深度）维度的成像分辨率支持分子水平表征。它将有可能记录3D图像，并以前所未有的细节水平描述细胞结构和成分，其空间分辨率比当前的MSI方法好一个数量级。

An award is made to Baylor University to develop an ultrahigh spatial resolution mass spectrometry imaging (MSI) instrument. The potential impact of this research is far-reaching because no current technology is available to address the existing shortcomings in high spatial resolution MSI. The direct beneficiaries of this state-of-the-art technology will include students, researchers, and the society as a whole. This work is expected to open the door for a variety of technology transfer opportunities and potential industry collaborations with the university for mass production that will yield significant economic and societal benefits. Two qualified undergraduate students from underrepresented groups from Baylor outreach programs will be recruited to gain quality research experience. Moreover, two graduate students and a scientist will be trained in research activities and develop expertise in MSI to broaden their scientific knowledge. Research findings and presentations of all mentees in the project will be highlighted in annual Advanced Instrumentation Workshops that target undergraduate students and faculty mentors from Historically Black Colleges and Universities and Hispanic-serving institutions in Texas and nearby states. Virtual scientific networks will be used to disseminate research findings and promote new collaborations. These NSF supported activities will be used to broaden underrepresented student group participation in future biological MSI research. This research will allow construction of a cutting-edge molecular imaging instrument that will be accessed by Baylor faculty and students and utilized for teaching advanced instrumentation classes and to promote inter-institution collaborations. Outcomes from this research will be disseminated through publications and conference presentations to boost broader use of the new ultrahigh spatial resolution MSI.Mass spectrometry imaging (MSI) provides information on surface morphology but also generates highly desired details about specific molecular identities of different sample components. In conventional MSI, a primary laser or desorption beam is rastered across a sample surface to desorb and subsequently analyze different components of biological tissues to construct three-dimensional images. Hence, the spatial resolution in MSI is limited by desorption beam's dimensions (or laser footprint) and energy threshold required to desorb a sufficient number of substrate molecules from the surface for subsequent ionization and mass analysis. Moreover, low ionization efficiencies can severely limit both sensitivity and spatial resolution (typically to several microns) for characterization of cellular components. The purpose of this research is to provide novel analytical capabilities for highly specific and sensitive characterization of cell organelles at the molecular level. This project will create a new frontier in MSI by combining focused ion beam (FIB) neutral desorption with a newly discovered and highly efficient radio frequency ionization (RFI). Persistent challenges in subcellular MSI include achievement of adequate detection sensitivity, overcoming ionization bias, minimizing potential migration of substrate constituents during the analysis, and improving spatial resolution. Current MSI strategies typically address one of these challenges at the expense of another. To ameliorate current trade-offs in MSI, geometry of an RFI source will be optimized to ionize substantially larger portion of the desorbed neutral plume than currently possible. The unparalleled sensitivity of RFI is expected to reduce the primary beam power requirements for a liquid metal ion source (LMIS) to such an extent that imaging resolution in the x-y (surface) and z (depth) dimensions will support molecular level characterization. It will be possible to record 3D images and characterize cell structures and compositions to an unprecedented level of detail, with spatial resolutions an order of magnitude better than current MSI approaches.