Functionalized Polymers as Receptors for Detection of Cells

2011 ◽  
Vol 64 (9) ◽  
pp. 1256 ◽  
Author(s):  
Miroslava Polreichova ◽  
Usman Latif ◽  
Franz L. Dickert

Mass sensitive sensors were applied for fast and label-free detection of bio-analytes. Robust and miniaturized sensor devices were fabricated by combining bio-mimetic imprinted surfaces with quartz crystal microbalances for the analysis of yeast and bacteria cells. These sensors allow us to differentiate between different growing stages of yeast cells. Moreover, the viability of cells was detected by structuring quartz crystal microbalance electrodes like a grid. Artificial yeast cells were produced to pattern the recognition layer, giving reversible enrichment of the respective bio-analytes. This approach was followed to ensure the reproducibility of the identical sensitive material in each case, because the properties of each cell depend on its growth stage, which varies over time. The strategy was further applied to develop a sensitive system for Escherichia coli. Structuring of these materials by soft lithography allows differentiation between cell strains, e.g. E. coli (strain W & B) with a five-fold selectivity.

Sensors ◽  
2020 ◽  
Vol 20 (19) ◽  
pp. 5506
Author(s):  
Yufeng Hu ◽  
Hanwen Xing ◽  
Gang Li ◽  
Minghuo Wu

Tiny changes in the mass of the sensor in a quartz crystal microbalance with dissipation monitoring (QCM-D) can be observed. However, the lack of specificity for target species has hindered the use of QCM-D. Here, molecularly imprinted polymers (MIPs) were used to modify a QCM-D sensor to provide specificity. The MIPs were formed in the presence of sodium dodecyl benzene sulfonate. Imprinted layers on Fe3O4 nanoparticles were formed using pyrrole as the functional monomer and cross-linker and methylene blue (MB) as a template. The MIPs produced were then attached to the surface of a QCM-D sensor. The MIPs-coated QCM-D sensor could recognize MB and gave a linear response in the concentration range 25 to 1.5 × 102 µg/L and a detection limit of 1.4 µg/L. The QCM-D sensor was selective for MB over structural analogs. The MIPs-coated QCM-D sensor was successfully used to detect MB in river water and seawater samples, and the recoveries were good. This is the first time MB has been detected using a QCM-D sensor. Mass is an intrinsic property of matter, so this method could easily be extended to other target species by using different MIPs.


The Analyst ◽  
2021 ◽  
Author(s):  
Gaozhe Cai ◽  
Wenshuai Wu ◽  
Shilun Feng ◽  
Yuanjie Liu

An enzyme assay based method in microfluidic slipchip was proposed for rapid and label-free detection of E. coli. The specific target analyte of E. coli was β-D-Glucuronidase (GUS) which could...


Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5473
Author(s):  
Yulan Tian ◽  
Tao Liang ◽  
Ping Zhu ◽  
Yating Chen ◽  
Wei Chen ◽  
...  

The detection of bacterial deoxyribonucleic acid (DNA) is of great significance in the quality control of food and water. In this study, a light-addressable potentiometric sensor (LAPS) deposited with highly oriented ZnO nanorod arrays (NRAs) was used for the label-free detection of single-stranded bacterial DNA (ssDNA). A functional, sensitive surface for the detection of Escherichia coli (E. coli) O157:H7 DNA was prepared by the covalent immobilization of the specific probe single-stranded DNA (ssDNA) on the LAPS surface. The functional surface was exposed to solutions containing the target E. coli ssDNA molecules, which allowed for the hybridization of the target ssDNA with the probe ssDNA. The surface charge changes induced by the hybridization of the probe ssDNA with the target E. coli ssDNA were monitored using LAPS measurements in a label-free manner. The results indicate that distinct signal changes can be registered and recorded to detect the target E. coli ssDNA. The lower detection limit of the target ssDNA corresponded to 1.0 × 102 colony forming units (CFUs)/mL of E. coli O157:H7 cells. All the results demonstrate that this DNA biosensor, based on the electrostatic detection of ssDNA, provides a novel approach for the sensitive and effective detection of bacterial DNA, which has promising prospects and potential applications in the quality control of food and water.


2011 ◽  
Vol 26 (7) ◽  
pp. 3367-3370 ◽  
Author(s):  
Reshma Bharadwaj ◽  
V.V.R. Sai ◽  
Kamini Thakare ◽  
Arvind Dhawangale ◽  
Tapanendu Kundu ◽  
...  

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