Abstract
A simple method of nanoparticle decoration can be used in the detection of pneumococcus. After the pneumococcal bacteria were captured by an antibody (pneumococcal C-polysaccharide (PnC) antibody) between the interdigitated electrodes, the gold nanoparticles conjugated with the PnC antibodies were let to bind onto an outer membrane of the bacteria. Upon successfully dense decoration, the bacteria surface will become conductive owing to the metal nanoparticles, and a distinctive conductance change between the electrodes can be observed. Since this success ratio, or the probability of the conductance change, reflects the concentration of the analyte, a number of repeated measurements can be used in the quantification of the bacteria. In this way, we have successfully detected S. pneumoniae in the range of 10–108 CFU/mL. The limit of detection in this work is lower than that in the commercial detection kit. We hope that the nanoparticle decoration method will play a role in the facile detection of various bacteria.
Highlights
The established method of bacteria analysis as standard protocols has been the bacterial culture and metabolic test [1]
The bacteria were selectively captured by the PnC antibody on the SiO2 surface between the electrodes so as to attain the probability of forming the electrical conduction bridge after the nanoparticle decoration
There can be some adhesion of probe particles on the device surface that is not mediated by the bacteria
Summary
The established method of bacteria analysis as standard protocols has been the bacterial culture and metabolic test [1]. Some recent works include reports on the direct electric detection of pathogenic bacteria. Lu et al showed that a direct electrical measurement of E. coli was possible when the experimental conditions are very carefully controlled [12]; recently, Mannoor et al reported the electronic detection of E. coli based on antimicrobial peptide-functionalized microcapacitive electrode arrays [13]. The key observed value in these electrical methods is the change in electrical properties such as conductance and impedance, which can be greatly enhanced when the metal nanoparticles are incorporated in the detection scheme. We used gold nanoparticles to decorate the surface of immobilized bacteria in the gap region of a microgap device, and the electrical conductance change upon the nanoparticle decoration was interpreted as the sign of the existence of bacteria. By counting the number of devices showing the conductance jump, we were able to quantify the S. pneumoniae at various concentrations
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
