Rapid detection of Legionella pneumophila (L. pneumophila) is important for monitoring the presence of these bacteria in water sources and preventing the transmission of the Legionnaires’ disease. We report improved biosensing of L. pneumophila with a digital photocorrosion (DIP) biosensor functionalized with an innovative structure of cysteine-modified warnericin antimicrobial peptides for capturing bacteria that are subsequently decorated with anti-L. pneumophila polyclonal antibodies (pAbs). The application of peptides for the operation of a biosensing device was enabled by the higher bacterial-capture efficiency of peptides compared to other traditional ligands, such as those based on antibodies or aptamers. At the same time, the significantly stronger affinity of pAbs decorating the L. pneumophila serogroup-1 (SG-1) compared to serogroup-5 (SG-5) allowed for the selective detection of L. pneumophila SG-1 at 50 CFU/mL. The results suggest that the attractive sensitivity of the investigated sandwich method is related to the flow of an extra electric charge between the pAb and a charge-sensing DIP biosensor. The method has the potential to offer highly specific and sensitive detection of L. pneumophila as well as other pathogenic bacteria and viruses.
Bacillus cereus (Bc) group are spore-forming bacteria that include human pathogenic strains, such as Bacillus cereus and Bacillus anthracis. Detection of Bc group spores using selective media is a laborious process that is largely dependent on the laboratory environment. We have examined the application of so-called digital photocorrosion (DIP) GaAs/AlGaAs biosensor for detection of Bacillus thuringiensis (Bt) spores. With the aptamer-based biosensing architecture, we have successfully demonstrated detection of Bt spores in the range between 10 3 -10 5 spores/mL. The ease of operating DIP biosensors, and the potential for sensitive detection in field settings hold the promise of attractive applications of these innovative devices for monitoring the presence of Bc group spores.
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