A group of researchers based at Osaka Metropolitan University have claimed that their new handheld device can detect multiple bacteria in food products electrochemically using organic metallic nanohybrids.
The team has shared that the rapid detection of pathogens including E. coli and Salmonella is “crucial in preventing outbreaks of foodborne illness”.
Typically, practices to detect bacterial contamination involves testing food samples in a laboratory to asses the type and quantity of bacteria that forms in a petri dish over a span of days. However the Osaka Metropolitan University research team have claimed their novel handheld device allows for “quick on-site detection”.
The study was led by Professor Hiroshi Shiigi of the Graduate School of Engineering and was published in the journal Analytical Chemistry. The research group experimented with a biosensor that can “simultaneously detect multiple disease-causing bacterial species within an hour”.
“The palm-sized device for detection can be linked to a smartphone app to easily check bacterial contamination levels,” commented Professor Shiigi.
To carry out the study, the team synthesised organic metallic nanohybrids of gold and copper that do not interfere with each other, so that electrochemical signals can be distinguished on the same screen-printed electrode chip of the biosensor. These organic−inorganic hybrids are made up of conductive polymers and metal nanoparticles. Following this, the antibody for the specific target bacteria was introduced into these nanohybrids to serve as electrochemical labels.
Results of the study confirmed that the synthesised nanohybrids functioned as efficient electrochemical labels, enabling the simultaneous detection and quantification of multiple bacteria in “less than an hour”.
“This technique enables rapid determination of the presence or absence of harmful bacteria prior to shipment of food and pharmaceutical products, thereby helping to quickly ensure safety at the manufacturing site,” continued Professor Shiigi.
Looking to the future, the research team has said that it is looking to develop new organic metallic nanohybrids to simultaneously detect additional bacterial species.
Abstract
Simultaneous Electrochemical Detection of Multiple Bacterial Species Using Metal–Organic Nanohybrids
Organic metallic nanohybrids (NHs), in which many small metal nanoparticles are encapsulated within a conductive polymer matrix, are useful as sensitive electrochemical labels because the constituents produce characteristic oxidation current responses. Gold NHs, consisting of gold nanoparticles and poly(m-toluidine), and copper NHs, consisting of copper nanoparticles and polyaniline, did not interfere with each other in terms of the electrochemical signals obtained on the same electrode. Antibodies were introduced into these NHs to function as electrochemical labels for targeting specific bacteria. Electrochemical measurements using screen-printed electrodes dry-fixed with NH-labeled bacterial cells enabled the estimation of bacterial species and number within minutes, based on the distinct current response of the labels. Our proposed method achieved simultaneous detection of enterohemorrhagic Escherichia coli and Staphylococcus aureus in a real sample. These NHs will be powerful tools as electrochemical labels and are expected to be useful for rapid testing in food and drug-related manufacturing sites.