Antibody assisted graphene oxide coated gold nanoparticles for rapid bacterial detection and near infrared light enhanced antibacterial activity

Nowadays, foodborne disease emerging as major health concern, can add extra burden to our existing health system. Mostly, conventional method used to monitor the food bacterial contamination, but these methods are cumbersome, thus can't fulfil the needs of modern time. Currently, nanotechnology have emerged as a wonderful tool for bacterial detection. The unique optical and plasmonic properties of metallic nanoparticles make them exceptional and novel for their integration into biosensor for bacterial detection. In this work, graphene oxide (GO) coated gold nanoparticles (AuNPs) based hybrid antibody biosensor has been developed for fast, specific and higher sensitivity foodborne bacterial detection. Polyethylene glycol (PEG) grafted GO coated AuNPs were covalently conjugated with two different types of antibodies using well known EDC-NHS chemistry. Various spectrophotometric and microscopic techniques have been used to probe the sensitivity of prepared biosensor. A colorimetric and spectrophotometric change upto 10(3) and 10(2) CFU, respectively was observed by incubating probe for 5 min. with Escherichia coli and Salmonella typhimurium. Immobilized antibodies on hybrid nanoparticle biosensor are specific for bacteria, however prepared biosensor also exhibited specific photoablation of bacteria after infra-red (NIR) exposure. Rapid optical detection and extermination of foodborne bacteria were achieved by antibody functionalized hybrid nanoparticles based biosensor.