Integrated Electrostatic Capture and On-Chip Biochemical Detection of Airborne Viruses in Real-Time

Considerable loss of life, economic slowdown, and public health risk associated with the transmission of airborne respiratory pathogens was underscored by the recent COVID-19 pandemic. Airborne transmission of zoonotic diseases such as the highly pathogenic avian influenza (HPAI) and porcine reproductive and respiratory syndrome virus (PRRSV) has caused major disruptions to domestic and global food security. Current ambient air pathogen monitoring systems involves the collection of air samples from indoor settings suspected of viral contamination, followed by subsequent processing of capture samples to determine the presence and species of airborne viral matter. Nucleic acid amplification (NAA) techniques are considered the gold standard for pathogen diagnostics. Currently, the necessary extraction and purification of viral RNA from air collector systems prior to sample analysis is both time consuming and performed manually. A monitoring system with separate air sampling and biochemical detection procedures is prone to delay the response to emergent viral threats. In this work, the presented pathogen monitoring system overcomes these limitations related to extraction and purification of viral samples and lays the groundwork for a real-time monitor for airborne viral pathogens. A high flow electrostatic precipitator system, that uses small collection wells as counter electrodes for pathogen collection is demonstrated. Small volumes of reagent (30 L) required for biochemical detection is dispensed directly to the collection wells Finally, Integrated reverse-transcriptase loop-mediated isothermal amplification (RT-LAMP) is used for detection of captured viral matter within wells. On-chip heating of collection wells for RT-LAMP is enabled through the engineering of a transparent oven with two voltage-controlled heating elements, and colorimetric changes indicating presence of virus is monitored through a USB-Camera interface,integrated to the sensor platform. The design of such a system is presented with collection and detection steps controlled remotely using a linear actuator and servo-motor assembly for the transfer of the collection well from the electrostatic precipitator to the oven assembly for initiation of RT-LAMP detection, demonstrating the key feature of detection of airborne viruses without the need for extraction and purification of viral RNA. Experimental results demonstrate the remote deployment of this device for the detection of aerosolized SARS-CoV-2 virus like particles (VLPs), a model pathogen for SARV-CoV-2, under biosafety level 2 (BSL-2) conditions.