Abstract

S. aureus is one of important causes of disease, food poisoning in humans and animals. The generally methods for detection of S. aureus is time consuming. Therefore, a new method is necessary for rapid, sensitive and specific diagnosis of S. aureus. In the present study, two probes and a Bio-barcode DNA were designed for detection of S. aureus (Protein A). Firstly, magnetic nanoparticle (MNPs) and gold nanoparticle (AuNPs) were synthesized at 80 degrees C and 100 degrees C, respectively. The AuNPs and the MNPs were functionalized with probel, Bio-barcode DNA and probe2, respectively. Target DNA was added into the nanomaterial's system containing bio-barcode DNA-AuNPs-probel and probe2-MNPs to formed bio-barcode DNA-AuNPs-probel-target DNA-probe2-MNPs complex. The bio-barcode DNA-AuNPs-probel-target DNA-probe2-MNPs complex was separated with magnetic field. Finally, the bio-barcode DNA was released from surface of complex using DTT (0.8 M) and there was isolated of nanoparticles by magnetic field and centrifuge. The fluorescence intensity of bio-barcode DNA was measured in different concentrations of S. aureus (10(1) to 10(8) CFU mL(-1)) by fluorescence spectrophotometry. The results showed that standard curve was linearly from 10(2) to 10(7) CFU mL(-1). Limit of detection of bio-barcode assay for both PBS and real samples was 86 CFU mL(-1). (C) 2018 Elsevier B.V. All rights reserved.