Nanomechanical and microwave resonance sensing for characterization of individual virions and nanoparticles in atmospheric conditions
This dissertation focuses on Nanoelectromechanical-based Mass Spectrometry (NEMS-MS), an innovative technique for characterizing nanoparticles and biomolecules weighing above the working limit of commercial mass spectrometry tools. It suggests performing NEMS-MS under atmospheric conditions and enhancing its capabilities with a built-in focusing lens. Amid the COVID-19 pandemic, the study addresses urgent virus detection needs, proposing a label-free method using NEMS-MS for individual virus detection and characterization. Notably, the study achieves mass spectrometry measurement of the SARS-CoV-2 virus using a NEMS-MS system operating entirely under atmospheric pressure. As the first to pioneer NEMS-MS in air, the study examines challenges tied to this, particularly how NEMS response in dissipative environments, known as Mode Shape Attenuation. Mathematical models and experiments dissect factors contributing to this attenuation, resulting in improved mass spectra and contributing toward the utilization of NEMS-MS for real-world application. Taking innovation a step further, the study introduces a microwave-based sensor for inferring electrical properties of nanoparticles. This sensor works in the electro-magnetic domain, determining properties like dielectric constant and expanding the sensing possibilities. Overall, this dissertation propels NEMS-based sensing and characterization by combining mass spectrometry, microwave sensing, and atmospheric pressure operation. Addressing challenges and introducing innovative solutions, it advances NEMS-MS technology and offers a cost-effective tool for characterizing nanoparticles and biomolecules across various applications.