Towards Real-Time Surveillance of Airborne Allergens Using a Biosensor-based Indoor Air Quality Monitoring Platform

DAS BEDADEEP, Meng Xu, Joshin Kumar, Shu-Wen You, Rajan K. Chakrabarty, Washington University in St. Louis

     Abstract Number: 141
     Working Group: Bioaerosols

Abstract
Airborne spores from the common indoor molds Penicillium chrysogenum and Aspergillus versicolor are small enough to reach deep into the lungs. In individuals prone to allergies, they can trigger sneezing, itchy eyes, and asthma, while repeated exposure keeps the airways inflamed. A. versicolor also produces the toxin sterigmatocystin, which adds a potential cancer risk. These invisible threats make the rapid detection of these allergens essential for public health.

To meet that need, we built a simple, label-free electrochemical sensor that measures these allergens, enabling rapid on-site detection. The device begins with a low-cost, screen-printed carbon electrode coated with Prussian Blue, which stores electrical charge well, and graphene oxide, which facilitates charge flow. Aptamers specific to the allergens are then fixed to the surface to bind to the allergens from both molds. The aptamer-allergen binding shifts the surface capacitance, as recorded by electrochemical impedance spectroscopy, thus enabling the detection of allergens in the solution. For real-world trials, the sensor couples with a wet cyclone bioaerosol sampler, which spins indoor air, traps particles in a drop of liquid, and feeds that sample directly to the biosensor, linking collection and detection of allergens in one step. Given its rapid readout, disposable format, and broad sensing range, the sensor serves as a practical early-warning tool for homes, schools, and workplaces. By flagging harmful mold allergens before symptoms appear, it supports timely ventilation, cleaning, or remediation and helps reduce both immediate respiratory problems and longer-term health risks.