The ability to track the concentrations of specific molecules in the body in real time would significantly improve our ability to study, monitor, and respond to diseases. To achieve this, we require sensors that can withstand the complex environment inside the body. Electrochemical aptamer-based sensors are particularly promising for in vivo sensing, as they are among the only generalizable sensing technologies that can achieve real-time molecular monitoring directly in blood and the living body. In this project, we first focused on extending the application space of aptamer sensors to support minimally-invasive wearable measurements. To achieve this, we developed individually-addressable sensors with commercial off-the-shelf microneedles. We demonstrated sensor function in buffer, blood, and porcine skin (a common proxy for human skin). In addition to the applied sensing project, we also worked to improve fundamental understanding of the aptamer sensing platform and how it responds to biomolecular interferents. Specifically, we explored the interfacial dynamics of biofouling – a process impacting sensors placed in complex fluids, such as blood.
Severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) can be spread through close contact or through fomite mediated transmission. This study details the fabrication and analysis of a photocatalyst surface which can rapidly inactivate SARS-COV-2 to limit spread of the virus by fomite mediated transmission. The surface being developed at Sandia for this purpose is a minimally hazardous Ag-Ti0 2 nanomaterial which is engineered to have high photocatalytic activity. Initial results at Sandia California in a BSL-2 safe surrogate virus- Vesicular Stomatitis Virus (VSV) show a significant difference between the photocatalyst material under exposure to visible light than controls. Additionally, UV-A light (365 nm) was found to eliminate SARS-COV-2 after 9 hours on all tested surfaces with irradiance of 15 mW/cm 2 equivalent to direct circumsolar irradiance.
Next generation pulsed power (NGPP) machines and accelerators require a better understanding of the materials used within the vacuum vessels to achieve lower base pressures (P << 10-5 Torr) and reduce the overall contaminant inventory while incorporating various dielectric materials which tend to be unfavorable for ultra-high vacuum (UHV) applications. By improving the baseline vacuum, it may be possible to delay the onset of impedance collapse, reduce current loss on multi-mega Amp devices, or improve the lifetime of thermionic cathodes, etc [3]. In this study, we examine the vacuum outgassing rate of Rexolite® (cross-linked polystyrene) and Kel-F® (polychlorotrifluoroethylene) as candidate materials for vacuum insulators [1]. These values are then incorporated into boundary conditions for molecular flow simulations using COMSOL Multiphysics® and used to predict the performance of a prototypical pulsed power system designed for 10-8 Torr operations.