Quartz crystal microbalance biosensor for rapid detection of aerosolized microorganisms

Abstract

Biological warfare agents (BWAs) represent the current menace of the asymmetric war. The early detection of BWAs, especially in the form of bioaerosol, is a challenging task for governments all around the world. Label-free quartz crystal microbalance (QCM) immunosensor and electrochemical immunosensor were developed and tested for rapid detection of BWA surrogate (E. coli) in the form of bioaerosol. Two immobilization strategies for the attachment of antibody were tested; the gold sensor surface was activated by cysteamine and then antibody was covalently linked either using glutaraldehyde, or the reduced antibodies were attached via Sulfo-SMCC. A portable bioaerosol chamber was constructed and used for safe manipulation with aerosolized microorganisms. The dissemination was done using a piezoelectric humidifier, distribution of bioaerosol inside the chamber was ensured using three 12-cm fans. The whole system was controlled remotely using LAN network. The disseminated microbial cells were collected and preconcentrated using the wetted-wall cyclone SASS 2300, the analysis was done using the on-line linked immunosensors. The QCM immunosensor had limit of detection 1×10 4 CFU·L −1 of air with analysis time 16 min, the whole experiment including dissemination and sensor surface regeneration took 40 min. In case of blank (disseminated sterile buffer), no signal change was observed. The electrochemical immunosensor was able to detect 150 CFU·L −1 of air in 20 min; also in this case, no interferences were observed. Reference measurements were done using particle counter Met One 3400 and by cultivation method on agar plates. The sensors have proved to be applicable for rapid screening of microorganisms in air.

Recent Advances in Monitoring, Sampling, and Sensing Techniques for Bioaerosols in the Atmosphere

“…Dissemination of microbial cells used a piezoelectric humidifier, and collection for preconcentration used a wetted-wall cyclone SASS 2300. 81 The QCM immunosensor offered an LOD of 1 × 10 4 CFU/L over 40 min (time for dissemination plus sensor surface regeneration). In contrast, the electrochemical biosensor provided a LOD value of 150 CFU/L of air over 20 min.…”

“…A label-free QCM immunosensor and electrochemical biosensor were fabricated to identify aerosolized BWAs; this system was often employed to measure model microbes (E. coli) in the form of bioaerosols. 81 The authors used two immobilization strategies for antibody conjugation. In the first step, the gold sensor surface was activated by cysteamine.…”

“…In contrast, the electrochemical biosensor provided a LOD value of 150 CFU/L of air over 20 min. 81 Identification and detection of airborne B. anthracis spores has drawn a great deal of attention since the anthrax-spore mailing of 2001. 83 An integrated air sampler and piezoelectric-excited millimetersized cantilever (PEMC) immunosensor was introduced to detect airborne B. anthracis spores.…”

“…79 Among the sensing methods, the lowest LOD of 1.5 × 10 2 CFU/L was achieved by an electrochemical biosensor based on signal amplification and heterogeneous format using peroxidase. 81 The highest LOD of 2.32 × 10 5 CFU/L was reported by a paper disk immobilized with luciferase/Dluciferin toward E. coli. 95 On the other hand, the lowest measurement time between 30 s and 2 min was obtained by an ATP bioluminescence assay for detection of Staphylococcus epidermidis bacteria.…”

Challenges and Perspectives for Biosensing of Bioaerosol Containing Pathogenic Microorganisms

“…The QCM biosensor measures the change in the frequency of quartz crystal resonator resulting from the mass change. Generally, the antibodies are modified onto the gold surface of the quartz crystal resonator to specifically capture the targets in the bioaerosols, resulting in the increase in the mass on the surface and thus the decrease in the resonation frequency [ 108 , 109 ]. Skladal et al proposed a QCM biosensor, which was able to detect the bioaerosols containing Escherichia coli with a lower detection limit of 1.45 × 10 4 CFU/L in 16 min [ 110 ].…”