Details

Autor(en) / Beteiligte

• Zhong, Miao
• Yang, Lu
• Yang, Hui
• Cheng, Chang
• Deng, Wenfang
• Tan, Yueming
• Xie, Qingji
• Yao, Shouzhuo

Titel

An electrochemical immunobiosensor for ultrasensitive detection of Escherichia coli O157:H7 using CdS quantum dots-encapsulated metal-organic frameworks as signal-amplifying tags

Ist Teil von

• Biosensors & bioelectronics, 2019-02, Vol.126, p.493-500

Ort / Verlag

England: Elsevier B.V

Erscheinungsjahr

2019

Quelle

MEDLINE

Beschreibungen/Notizen

• We report here cadmium sulfide quantum dots (CdS QDs)-encapsulated metal-organic frameworks as signal-amplifying tags for ultrasensitive electrochemical detection of Escherichia coli O157:H7 (E. coli O157:H7). CdS QDs were encapsulated in zeolitic imidazolate framework-8 (ZIF-8) to form CdS@ZIF-8 muti-core-shell particles by in situ growth of ZIF-8 in the presence of CdS QDs. To specifically recognize E. coli O157:H7 cells, CdS@ZIF-8 particles were coated with polyethyleneimine to introduce amino groups on their surfaces, followed by surface modification of anti-E. coli O157:H7 antibody. A sandwich-type electrochemical immunobiosensor for the detection of E. coli O157:H7 was fabricated using CdS@ZIF-8 particles as signal tags. Cd(II) ions were released from CdS@ZIF-8 tags by HCl leaching, enabling the detection of E. coli O157:H7 by differential pulse voltammetry. Under the optimized conditions, the linear range of the biosensor is from 10 to 108 colony forming units (CFU) per mL for E. coli O157:H7 detection, with the detection limit of 3 CFU mL−1 (S/N = 3). The sensitivity of the biosensor for E. coli O157:H7 detection using CdS@ZIF-8 particles as signal tags is 16 times that of a biosensor using CdS QDs as signal tags, because the number of CdS QDs labeled to each bacterial cell increases greatly resulting from a great number of CdS QDs encapsulated in each CdS@ZIF-8 label. This method was successfully used to detect E. coli O157:H7 in milk samples. •CdS QDs were encapsulated in zeolitic imidazolate framework-8 (ZIF-8) to form CdS@ZIF-8 muti-core-shell nanoparticles.•A sandwich-type electrochemical immunobiosensor was fabricated using CdS@ZIF-8 nanoparticles as signal-amplifying tags.•The electrochemical signals were amplified greatly by using CdS@ZIF-8 nanoparticles as signal tags.•The detection limit for E. coli O157:H7 detection is 3 CFU mL−1 (S/N = 3).•The immunobiosensor was successfully used to detect E. coli O157:H7 in milk samples.