title: Aptamer-fluorescent silica nanoparticles bioconjugates based dual-color flow cytometry for specific detection of Staphylococcus aureus.
abstract: This paper describes a sensitive and specific determination strategy for Staphylococcus aureus (S. aureus) detection using aptamer recognition and fluorescent silica nanoparticles (FSiNPs) label based dual-color flow cytometry assay (Aptamer/FSiNPs-DCFCM). In the protocol, an aptamer, having high affinity to S. aureus, was first covalently immobilized onto chloropropyl functionalized FSiNPs through a click chemistry approach to generate aptamer-nanoparticles bioconjugates (Aptamer/FSiNPs). Next, S. aureus was incubated with Aptamer/FSiNPs, and then stained with SYBR Green I (a special staining material for the duplex DNA). Upon target binding and nucleic acid staining with SYBR Green I, the S. aureus was determined using two-color flow cytometry. The method took advantage of the specificity of aptamer, signal amplification of FSiNPs label and decreased false positives of two-color flow cytometry assay. It was demonstrated that these Aptamer/FSiNPs could efficiently recognize and fluorescently label target S. aureus. Through multiparameter determination with flow cytometry, this assay allowed for detection of as low as 1.5 x 10(2) and 7.6 x 10(2) cells mL(-1) S. aureus in buffer and spiked milk, respectively, with higher sensitivity than the Aptamer/FITC based flow cytometry.
authors.forename: Xiaoxiao
authors.initials: X
authors.lastname: He
authors.forename: Yuhong
authors.initials: Y
authors.lastname: Li
authors.forename: Dinggen
authors.initials: D
authors.lastname: He
authors.forename: Kemin
authors.initials: K
authors.lastname: Wang
authors.forename: Jingfang
authors.initials: J
authors.lastname: Shangguan
authors.forename: Hui
authors.initials: H
authors.lastname: Shi
mesh_terms: D000818:Animals; D052157:Aptamers, Nucleotide / Q000737:chemistry*; D002021:Buffers; D005240:Feasibility Studies; D005434:Flow Cytometry / Q000379:methods*; D016650:Fluorescein-5-isothiocyanate / Q000378:metabolism; D018613:Microscopy, Confocal; D008892:Milk / Q000382:microbiology; D058726:Nanoconjugates / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D012822:Silicon Dioxide / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013211:Staphylococcus aureus / Q000302:isolation & purification*
chemical_list: D052157:Aptamers, Nucleotide; D002021:Buffers; D058726:Nanoconjugates; D012822:Silicon Dioxide; D016650:Fluorescein-5-isothiocyanate