Sensing Escherichia coli O157:H7 via frequency shift through a self-assembled monolayer based QCM immunosensor

Abstract

By means of the specific immuno-recognition and ultra-sensitive mass detection, a quartz crystal microbalance (QCM) biosensor for Escherichia coli O157:H7 detection was developed in this work. As a suitable surfactant, 16-mercaptohexadecanoic acid (MHDA) was introduced onto the Au surface of QCM, and then self-assembled with N-hydroxysuccinimide (NHS) raster as a reactive intermediate to provide an active interface for the specific antibody immobilization. The binding of target bacteria with the immobilized antibodies decreased the sensor's resonant frequency, and the frequency shift was correlated to the bacterial concentration. The stepwise assembly of the immunosensor was characterized by means of the electrochemical techniques. Using the immersion-dry-immersion procedure, this QCM biosensor could detect 2.0×10 2 colony forming units (CFU)/ml E. coli O157:H7. In order to reduce the fabrication time, a polyelectrolyte layer-by-layer self-assembly (LBL-SA) method was adopted for fast construction. Finally, the reproducibility of this biosensor was discussed.

A Quartz Crystal Microbalance Immunosensor for Stem Cell Selection and Extraction

“…For this reason, in the liquid-phase, a term containing the viscosity (η L ) and the density ( L ) of the solution should be taken into account. Nevertheless, as reported by Wang et al [ 26 ], in the static liquid-phase measurement, the viscosity and the density of the background buffer are constant in each measurement, so their contribution can be overlooked. Based on these considerations, the mass change and the amounts of molecules of each layer on the gold surface were calculated using the following equation [ 26 ]: …”

“…The immunoassay format, based on antibody–antigen (Ab–Ag) interactions, remains a robust, ubiquitous analytical tool [ 21 ]. Indeed, a number of QCM immunosensors [ 22 ] have been reported for the determination of different analytes, such as glucose [ 4 ], microbes [ 23 , 24 , 25 , 26 , 27 ], nucleic acids [ 28 , 29 ], environmental pollutants [ 30 ], cells [ 31 ], and food pathogens [ 32 ], for drug discovery applications, and for diagnostics and biomedical applications [ 33 ].…”

A survey of the 2006–2009 quartz crystal microbalance biosensor literature

“…Escherichia coli W1485 was detected using a functional mannose self‐assembled monolayer in combination with the lectin concanavalin A (Con A) which binds to the polysaccharide envelope of the bacteria (Shen et al ., 2007c); the linear range was from 7.5 × 10 2 to 7.5 × 10 7 cells/mL. E. coli O157:H7 was detected using specific antibodies (Wang et al ., 2008b) and a DNA sensor with nanoparticle amplification was used to detect E. coli O157:H7 down to concentrations as low as 10 −12 M of synthetic oligonucleotide and 2.7 × 10 2 cfu/mL of bacteria (Mao et al , 2006). The effect of the spacer on hybridization was also investigated for E. coli O157:H7 DNA detection (Wu et al , 2007).…”

A high sensitive electrochemical nanoimmunosensor based on Fe3O4/TMC/Au nanocomposite and PT-modified electrode for the detection of cancer biomarker epidermal growth factor receptor

“…Many different approaches such as polymer membrane, protein G, and self-assembled monolayer (SAM) have been adopted to improve the efficiency of immobilization [42,45]. However, polymer based techniques have attracted considerable attention from scientists due to providing a reproducible, thin, and well-ordered functional layer for antibody immobilization.…”