A low burden broad-spectrum electrochemical pathogen sensor in a field trial

Timely detection of pathogens is crucial for environmental monitoring, biological defence, medical diagnostics, public safety and security. Conventional detection and identification methods are often slow, costly and impractical for field analysis, delaying early interventions and disease containment. This work shows an integrated platform using electro-impedance spectroscopy (EIS) and digital microfluidic (DMF) technologies to enable rapid, multiplexed detection of pathogens. The scientific foundation lies in exploiting TLR–PAMP (Toll-like receptor – pathogen-associated molecular pattern) interactions to provide a broad-spectrum, label-free sensing mechanism capable of distinguishing diverse airborne pathogens in near-real time.

The detection platform consists of a multiplexed three-electrode EIS biosensor integrated with a DMF system. Four working electrodes are functionalized with different TLRs to recognize specific PAMPs. Aerosolized pathogen simulants were generated in controlled and field conditions, collected using commercial and custom bioaerosol collectors, and analyzed on the DMF device. Impedance changes before and after sample exposure indicate the presence and types of pathogens, and the results were validated against quantitative PCR (qPCR) and lateral flow assay (LFA) measurements.

The multiplexed and integrated EIS biosensor successfully detected and differentiated aerosolized pathogen simulants within 30 minutes. TLR4 sensors exhibited pronounced impedance responses to gram-negative bacteria (Pantoea agglomerans and E. coli) compared to aerosol blanks and mixed samples with Bacillus atrophaeus spores (BG), demonstrating high specificity and sampler effectiveness. TLR2/6 sensors responded distinctly to BG spores, enabling qualitative comparison of bioaerosol collectors performance. Additionally, bioaerosol sample analyses confirmed measurable signal changes above background levels, validating the sensor’s capability for near-real-time, in-field detection and classification of airborne pathogens.

These findings represent a significant advancement in portable, multiplexed biosensing technologies for pathogen monitoring. This approach bridges the gap between laboratory-based diagnostics and field-deployable environmental monitoring tools, supporting rapid, broad-spectrum detection platforms that strengthen public safety and security through early identification of emerging microbial threats.