[Detection of Escherichia coli O157:H7 with piezoelectric immunosensor based on enhancement with immuno-nanoparticles].Wei Sheng Wu Xue Bao. 2009 Jun; 49(6):820-5.WS
We developed a sensitive method to detect Escherichia coli O157:H7 based on enhancement with immuno-nanoparticles.
About 10 nm ultrafine immunomagnetic particles were prepared by a co-precipitation method, about 20 nm immuno-colloid-gold was prepared by sodium citrate reduction. The immunosensor was fabricated by using Protein A from Staphylococcus aureus (SPA) for the antibody immobilization. Two immuno-nanoparticles by two antibodies were used to amplify frequency changing.
The most suitable immobilization concentration and time for SPA was 1.2 mg/mL and 40 min, and dose for the antibody was 1.0 mg/mL and 60 min. With the signal amplification of the two immuno-nanoparticles, the detection limit of E. coli O157:H7 was increased from 10(4) colony-forming units (cfu)/mL to 10(1) cfu/mL.
The prepared immuno-nanoparticles might be used to significantly amplify the frequency signal of the piezoelectric immunosensor and improve the detect sensitivity.