Label-Free Detection of Gliadin in Food by Quartz Crystal Microbalance-Based Immunosensor

2017 ◽  
Vol 65 (6) ◽  
pp. 1281-1289 ◽  
Author(s):  
Riccardo Funari ◽  
Irma Terracciano ◽  
Bartolomeo Della Ventura ◽  
Sara Ricci ◽  
Teodoro Cardi ◽  
...  
Keyword(s):  
Quartz Crystal Microbalance ◽  
Quartz Crystal ◽  
Label Free ◽  
Label Free Detection

scholarly journals Magnetic Imprinted Polymer-Based Quartz Crystal Microbalance Sensor for Sensitive Label-Free Detection of Methylene Blue in Groundwater

Sensors ◽  
2020 ◽  
Vol 20 (19) ◽  
pp. 5506
Author(s):  
Yufeng Hu ◽  
Hanwen Xing ◽  
Gang Li ◽  
Minghuo Wu
Keyword(s):  
Methylene Blue ◽  
Quartz Crystal Microbalance ◽  
Quartz Crystal ◽  
Sodium Dodecyl ◽  
Sodium Dodecyl Benzene Sulfonate ◽  
Intrinsic Property ◽  
Label Free ◽  
Target Species ◽  
Label Free Detection ◽  
Seawater Samples

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.

scholarly journals Quantitative Assessment of Periodontal Bacteria Using a Cell-Based Immunoassay with Functionalized Quartz Crystal Microbalance

Chemosensors ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 159
Author(s):  
Satit Rodphukdeekul ◽  
Miyuki Tabata ◽  
Chindanai Ratanaporncharoen ◽  
Yasuo Takeuchi ◽  
Pakpum Somboon ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Quartz Crystal Microbalance ◽  
Quantitative Assessment ◽  
Quartz Crystal ◽  
Dynamic Range ◽  
Gold Surface ◽  
Enzyme Linked Immunosorbent Assay ◽  
Inflammatory Disorder ◽  
Label Free ◽  
Periodontal Bacteria

Periodontal disease is an inflammatory disorder that is triggered by bacterial plaque and causes the destruction of the tooth-supporting tissues leading to tooth loss. Several bacteria species, including Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans, are considered to be associated with severe periodontal conditions. In this study, we demonstrated a quartz crystal microbalance (QCM) immunoassay for quantitative assessment of the periodontal bacteria, A. actinomycetemcomitans. An immunosensor was constructed using a self-assembled monolayer of 11-mercaptoundecanoic acid (11-MUA) on the gold surface of a QCM chip. The 11-MUA layer was evaluated using a cyclic voltammetry technique to determine its mass and packing density. Next, a monoclonal antibody was covalently linked to 11-MUA using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide to act as the biorecognition element. The specificity of the monoclonal antibody was confirmed by an enzyme-linked immunosorbent assay. A calibration curve, for the relationship between the frequency shifts and number of bacteria, was used to calculate the number of A. actinomycetemcomitans bacteria in a test sample. Based on a regression equation, the lower detection limit was 800 cells, with a dynamic range up to 2.32 × 106 cells. Thus, the QCM biosensor in this study provides a sensitive and label-free method for quantitative analysis of periodontal bacteria. The method can be used in various biosensing assays for practical application and routine detection of periodontitis pathogens.

Functionalized Polymers as Receptors for Detection of Cells

2011 ◽  
Vol 64 (9) ◽  
pp. 1256 ◽  
Author(s):  
Miroslava Polreichova ◽  
Usman Latif ◽  
Franz L. Dickert
Keyword(s):  
Soft Lithography ◽  
Quartz Crystal ◽  
Coli Strain ◽  
Yeast Cells ◽  
Label Free ◽  
Sensitive Material ◽  
E Coli ◽  
Label Free Detection ◽  
Quartz Crystal Microbalances ◽  
Cell Strains

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.

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