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

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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.