Field Portable Bioaerosol Identification with Miniaturized MALDI TOF MS

All detection/identification systems face the same challenges which are summed up in what we call the five “S’s” – Sensitivity, Specificity, Speed, SWAP (size, weight, and power), and Co$t-per-Test. The tradeoffs between these factors determine the applicability of the detection/identification system to support operational needs. Our low cost is driven by the elimination of agent specific reagents. MALDI TOF MS uses commonly available chemicals and are not subject to the supply chain issues that plague PCR and immunoassay based bioidentifiers. Our detection method is based on MALDI (Matrix-Assisted Laser Desorption/Ionization) mass spectrometry, which over the past several years has become a gold standard clinical diagnostic tool. The Zeteo team has been developing this science and technology over several years. The system samples individual bioaerosol particles and uses laser-based, Time-of-Flight Mass Spectrometry (TOF MS) to determine the masses of the biomolecules (proteins, peptide, lipids, carbohydrates) across a wide mass range (100-100,000 Daltons). This technique was pioneered by the Zeteo team when employed at the Johns Hopkins University Applied Physics Laboratory (JHU-APL) and, in one format, has been commercially transitioned to clinical diagnostic laboratories worldwide where >10,000 different clinical isolates are accurately identified. This powerful technique measures specific threat signature masses derived directly from the genome of the threat organism, or toxin-producing organism, (analogous to PCR or WGS signatures) and are not class-generic spectral features typical of infrared or Raman approaches. While the bioidentifier has excellent specificity and sensitivity (~100 organism) for nucleic acid-containing microbes, it also has outstanding specificity and sensitivity (pg) for biological toxins, and other biochemical threats. The threat databases for the sensor can instantly be updated at the system level, as signatures and algorithms improve, and new threats are added. The effort proposed here combines a novel electrospray method to prepare particles for analysis, significantly reducing pumping size and power requirements. Ions are formed in a low vacuum region before entering the high vacuum of the mass analyzer. In Phase I we demonstrated the efficacy of each of the major system components. Leveraging on the successful results from our Phase I SBIR effort, we propose development and deployment of an advanced detection system that features non-invasive sampling, carries out automated sample preparation, provides an answer in < 1 minute, has high sensitivity (zeptomoles of sample), specific (based on Gold Standard Clinical Assays), and low-cost (pennies-per-test). We will also leverage our experience with AI processing of single particle MALDI spectra to demonstrate the ability to detect trace levels of threat agent (10’s of particles) in complex backgrounds.