digitalMALDI: A single particle-based mass spectrometric detection system for biomolecules

The development of a real-time system to analyze individual biomolecule-containing aerosol particles could provide a critical capability to diagnose lung disease rapidly. However, currently available technologies are mainly based on molecular assays, require costly reagents, and are relatively slow and challenging to multiplex. To address these limitations, we developed digitalMALDI™, a laser-based mass spectrometry-based system. In particular, digitalMALDI™ is a near real-time system that directly samples aerosols, eliminating the need for complex and time-consuming sample preparation and producing MALDI-MS spectra for individual aerosol particles. In this study, an intact insulin protein was used to demonstrate the feasibility of this approach. Results showed that digitalMALDI™ is sensitive to detecting ~1 picogram of insulin protein in single particles in real-time, suggesting that the system has a broad application for disease diagnosis, environmental monitoring, and biosecurity management.