This award supports the development of a mass spectrometer capable of mass analyzing mega-Dalton biomolecules with unprecedented sensitivity at Carnegie Mellon University. State-of-the-art mass spectrometers currently lack the combined sensitivity, resolution and mass accuracy necessary for routine analysis of singly-charged high molecular weight ions. This next-generation matrix-assisted laser desorption ionization (MALDI) ion trap mass spectrometer will be designed to overcome the high m/z (mass/charge) barrier. The project incorporates a cross-disciplinary collaborative effort by chemists, physicists and biologists both in academia and industry and should greatly impact the mass analysis of mega-Dalton biomolecules.
The proposed heavy-ion mass spectrometer will have ultra-high sensitivity by interfacing three innovative MS components: i.) a unique MALDI source, ii.) a mega-Dalton mass range ion trap and iii.) a detector with 100% detection efficiency at high mass. The goal is to analyze large molecules or complexes with m/z ranging from 10,000 to 15,000,000 at the attomole level. The development of this new instrument should provide breakthrough performance for the direct mass analysis of mega-Dalton biomolecules, bio-structures, non-covalent and covalent multi-protein complexes, protein/adducts, DNA and viruses. This project is directed at a long-term research goal of single cell proteomics.
The development and dissemination of a next-generation mass spectrometer for analysis of macromolecules will impact many fields. For the biological sciences, the proposed instrument should significantly advance research in proteomics, where the challenge is to identify all proteins and characterize all protein-protein interactions in a biological system. In addition, the instrument's capabilities should benefit the field of nanotechnology, which currently lacks a good method to characterize large molecules. To educate students and scientists about the heavy-ion mass spectrometer, presentations about this development will target both small colleges and major universities. The mega-Dalton mass spectrometer will be used to teach undergraduates, graduate students and post doctorial students about MS instrumentation development both in these presentations and in courses taught at Carnegie Mellon (Chem 09-543: Mass Spectrometry and Chem 09-445: Undergraduate Research). Undergraduate research positions will be offered to students from under-represented groups. To widen the impact to the greatest number of students, the development of the new spectrometer will be incorporated into a NSF Internet educational tool called the Virtual Mass Spectrometry Laboratory (http://svmsl.chem.cmu.edu).
This project focused on the need for mass spectrometry (MS) analysis of ultra-heavy molecules and complexes that cannot be achieved using conventional mass spectrometers. Conventional mass spectrometers lack one or more of the following signal qualities at high mass-to-charge ratios: sufficient mass range, signal sensitivity, mass accuracy and/or mass resolution. Enabling ultra-heavy mass analysis opens a new frontier in mass spectrometry research and provides valuable instrumentation for researchers in the fields of biology, material sciences and chemistry. We achieved analysis of heavy molecules by using cryodetector technology coupled to a time-of-flight mass spectrometer and developed a novel heavy ion mass spectrometer. Unlike conventional ion detectors, cryodetectors only require low impact energies to generate a signal and the signal level registered can reveal additional information about that ion. In designing and implementing the new instrument, we developed several novel features. These innovations include 1) improved ion optics to transmit and efficiently capture ions generated by the ion source, 2) methods to trap heavy ions in a linear ion trap, 3) novel ejection ion optics, and 4) methods to focus ions onto detectors. We have achieved unprecedented results using the cryodetector time-of-flight mass spectrometer to analyze ultra-heavy ions into the tens of MegaDalton mass range for virus particles and von Willebrand factor (+1MDa). In addition, we have analyzed gold nanoparticles and quantum dots, which are used in tissue imaging. We have obtained a spectrum for an antibody multimer, the largest singly-charged protein complex ever collected using a linear ion trap instrument. The impact of the virus data can be best understood when you consider that this type of information could be the first step as a rapid method for identification of viruses, which is of the utmost concern today with the influence of climate change on the potential for future epidemics. Further MS studies of von Willebrand factor, a key blood clotting protein complex, could lead to rapid testing and a better understanding of hemophilia. The use of cryodetector technology can also complement and provide improved information compared to other analytical methods used to characterize nanoparticles, which is a major focus of many researchers developing advanced materials for imaging and manufacturing advanced parts. Through the development of this instrument, several potential inventions have been disclosed to the Carnegie Mellon Technology Transfer Office. This work partially stimulated the conception of ideas included in a patent issued in 2010 and a continuation patent issued in 2013. During the funding period of this project, three postdoctoral fellows, one senior scientist, one master degree student and seven undergraduate students from Carnegie Mellon University were trained.
