This proposal describes key steps towards generating the first commercial charge detection mass spectrometer. Charge detection mass spectrometry (CDMS) is an emerging technology that can measure the masses of large heterogeneous biopharmaceuticals and nanoparticles. Current commercial mass spectrometers measure the mass-to-charge ratio (m/z) of ensembles of ions and require charge assignment to determine mass. Due to overlapping charge states this approach breaks down for masses above around a megadalton (MDa) even under favorable conditions. CDMS overcomes this limitation by simultaneously measuring the m/z and the z of individual ions. m/z and z are then multiplied to give m for each ion. By extending the upper mass limit by several orders of magnitude, CDMS has disruptive potential for the characterization and discovery of new therapeutics and disease markers in the same way current commercial mass spectrometers have had for small molecules. However, CDMS is currently only available in a few academic laboratories. To make it more widely available we will install a CDMS detector on a commercial quadrupole time of flight (Q-TOF) mass spectrometer. The CDMS detector will use technology developed in the Jarrold lab at Indiana University, and employed there for a number of years. The modification will be performed in a way that retains all the functionalities of the Q-TOF for light ions while adding the capability to analyze high mass ions by CDMS. A suite of molecules that can be detected by both conventional time of flight MS and CDMS will be used to calibrate the CDMS m/z and z measurements and evaluate the mass resolution. The high-mass performance of the hybrid Q-CDMS-TOF instrument will be evaluated with a number of high mass species (3-52 MDa) that have previously been measured by CDMS. Commercial instruments are not optimized to transmit very high mass ions so modifications will be made to the Q-TOF to improve the transmission efficiency. This new Q-CDMS-TOF instrument will extend MS far beyond the mass range of current commercial instruments, enabling measurements for entire new classes of biologics (e.g., vaccines and gene therapy products), nanoparticles (such as liposomes and solid lipid hybrids), large biomarkers (such as lipoproteins and exosomes), and many more yet to be identified. Because CDMS can analyze very heterogeneous samples, there are potential applications in diagnostic tests and in process control and monitoring during pharmaceutical formulations. Seven pharmaceutical companies have approached us with interest in purchasing CDMS instruments (two of these in the last month). Most of these contacts have led to research agreements and/or service contracts in order to characterize large molecule targets. We expect the interest from pharmaceutical companies to continue to grow as the measurements become more main stream. The development of a commercial Q-CDMS-TOF instrument for robust, high-throughput measurements is the key to meeting this growing need.
Charge detection mass spectrometry (CDMS) allows accurate molecular weights to be measured for samples (such as vaccines, liposomes, gene therapy vectors, and lipoproteins) that are well beyond the mass range of conventional mass spectrometers. This proposal outlines a plan to integrate CDMS into a commercial MS platform, a first step in commercializing CDMS. The availability of a commercial CDMS instrument will have wide ranging impact on human health, from better characterization of biopharmaceuticals to the development of new diagnostics and therapeutic targets.
