Colorimetric immunoassay for rapid detection of Staphylococcus aureus based on etching-enhanced peroxidase-like catalyti
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ORIGINAL PAPER
Colorimetric immunoassay for rapid detection of Staphylococcus aureus based on etching-enhanced peroxidase-like catalytic activity of gold nanoparticles Shuo Yao 1 & Juan Li 1 & Bo Pang 1 & Xuechen Wang 1 & Yujie Shi 1 & Xiuling Song 1 & Kun Xu 1 & Juan Wang 1 & Chao Zhao 1 Received: 10 February 2020 / Accepted: 4 August 2020 # Springer-Verlag GmbH Austria, part of Springer Nature 2020
Abstract A novel colorimetric immunoassay for the detection of Staphylococcus aureus (S. aureus) based on a combination of immunomagnetic separation and signal amplification via etching-enhanced peroxidase-like catalytic activity of gold nanoparticles (AuNPs) was developed. Nanoconjugates composed of gold and iron oxide nanoparticles were synthesized and further modified with antiS. aureus immunoglobulin Y (IgY), which was used for the selective enrichment and rapid separation of target bacteria in complex matrices. AuNPs functionalized with antiS. aureus aptamer were used as an artificial enzyme which has peroxidase-like catalysis activity. Catalytic activity of AuNPs is inhibited by modifying aptamer. However, catalysis of modified AuNPs remarkably enhanced by hydrogen peroxide etching. Based on collecting unbound modified AuNPs in the supernatant and 3,3′,5,5′-tetramethylbenzidine-hydrogen peroxide reporting system, the yellow color of solution decreases linearly with increasing the concentration of S. aureus ranging from 10 to 106 cfu/mL. The limit of detection is 10 cfu/mL, and total detection time is 65 min. The recoveries of the S. aureus spiked in food samples are 88.2–119.8%. Keywords Food safety . Foodborne pathogen . Visual detection . Immunomagnetic separation . Nanozyme . Etching-enhanced catalytic activity
Introduction Staphylococcus aureus (S. aureus) is a major foodborne pathogen and can produce enterotoxins causing diverse and serious diseases including local suppurative infection, pneumonia, pseudomembranous colitis, pericarditis, sepsis, and other systemic infections [1]. It is one of the top five pathogens contributing to acquired foodborne illnesses, causing an estimated a quarter of a million cases every year in the USA [2]. Therefore, it is urgent to develop a sensitive and specific method for the detection of S. aureus. Conventional detection methods, such as culture and biochemical test [3], polymerase Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00604-020-04473-7) contains supplementary material, which is available to authorized users. * Juan Wang [email protected] * Chao Zhao [email protected] 1
School of Public Health, Jilin University, Changchun 130021, China
chain reaction (PCR) [4], and enzyme-linked immunosorbent assays (ELISA) [5], have advantages of accuracy, specificity, and stability. However, these methods are not suitable for onsite detection of S. aureus due to their complex operation steps and long detection time [6]. To shorten the analysis time and simplify the operation procedure, the immunomagnetic separation (IMS)
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