Quartz crystal sensor

A chemical microsensor can be defined as an extremely small device that detects components in gases or Hquids (52—55). Ideally, such a sensor generates a response which either varies with the nature or concentration of the material or is reversible for repeated cycles of exposure. Of the many types of microsensors that have been described (56), three are the most prominent the chemiresistor, the bulk-wave piezoelectric quartz crystal sensor, and the surface acoustic wave (saw) device (57). 

Bulk-wave piezoelectric quartz crystal sensors indirecdy measure mass changes of the coating on the surface of the sensing device. This change in mass causes changes in the resonant frequency of the device, and measurements ate based on frequency differences. 

Nitz, S., Kollmannsberger, H., Lachermeier, C., Horner, G. (1999) Odour assessment with piezoelectric quartz crystal sensor array, a suitable tool for quality control in food technology Adv. Food. Sci. 21 136-150. 

A quartz crystal sensor chip was bonded with a microfluidic glass chip for acoustic wave detection (see Figure 7.46). The sensor was operated in the thickness-shear mode (TSM). This has allowed rat heart muscle cell contraction to be studied based on the measurement of the resonant frequency changes [133]. 

J.-M. Kim, S.M. Chang, Y. Suda and H. Muramatsu, Stability study of carbon graphite covered quartz crystal. Sensors and Actuators, A 72 (1999) pp. 140-147. Y.-C. Chao and J.-S. Shih, Adsorption study of organic molecules on fiillerene with piezoelectric crystal detection system. Anal. Chim. Acta, 374 (1998) pp. 39-46. 

Jersch J, Maletzky T, Fuchs H (2006) Interface circuits for quartz crystal sensors in scanning probe microscopy applications. Rev Sci Instrum 77 083701... 

Skladal, P. (2003) Piezoelectric quartz crystal sensors applied for bioanalytical assays and characterization of affinity interactions. Tournal of the Brazilian Chemical Society 14, 491-502... 

Fig. 5 Scheme of inverted MESA quartz crystal (a) and realized 4x4 quartz crystal sensor array (b). The membrane of each sensor element has been thinned with wet etching. The resonance frequency of each sensor could be elevated to frequencies up to 50 MHz. The analyte usually faces the flat (bottom) surface... 

Fig. 25 Interface with analog measurement of (quartz crystal) sensor impedance...

Efficient immobilization of aptamers on surfaces is necessary for the construction of tongh, stable sensors and assay systems as one necessary step to overcome limitations for practical applications (Bini et al., 2007). Bini et al. (2007) have compared thrombin aptamers immobilized on a gold snrface by chemisorption (thiolated aptamer) and by biotin-streptavidin interaction (biotinylated aptamer carrying a linker) on a gold surface modified by a thiol-dextran-streptavidin layer. The linker-modified aptamer immobilized via streptavidin-biotin showed better reproducibility and sensitivity results for the quartz crystal sensor. Aptamers can be used for the functionalization of titanium-alloy surfaces (e.g., implant material, scaffolds) to enhance cell adhesion. The aptamers directed to osteoblasts are fixed electrochemically on the snrface of the alloy and promote cell adhesion (Gno et al., 2005, 2007). 

C. Wang et al., A piezoelectric quartz crystal sensor array self-assembled calixarene bilayers for detection of volatile organic amine in gas. Talanta 57, 1181-1188 (2002)... 

J.-M. Kim, S.M. Chang, Y. Suda and H. Muramatsu, Stability study of carbon graphite coveted quartz crystal. Sensors and Actuators, A 72 (1999) pp. 140-147. 

The attachment of cells to CG hydrogel layered onto a surface of a quartz crystal sensor (QCM) reduces the resonant oscillation frequency by A/, = -75 Hz after the first cell injection (Figure 5.49, curve 1 at t<600 s). The second cell injection leads to the total A/i2 -105 Hz, i.e., IA(2lgain controller voltage (Figure 5.49, curve 2) that indicates cells interactions with the CG matrix. These frequency shifts can be interpreted in terms of mass addition at the sensor surface according to the equation... 

It should be evident from the above arguments that the term quartz crystal microbalance is a misnomer, which could (and indeed has) lead to erroneous interpretation of the results obtained by this useful device. It would be helpful to rename it the quartz crystal sensor (QCS), which describes what it really does—it is a sensor that responds to its nearest environment on the nano-scale. However, it may be too late to change the widely used name. The QCM or its analogue in electrochemistry, the EQCM, can each act as a nano-balance under specific conditions, but not in general. 

Lin H-B, Shih J-S (2003) Fullerene C -cryptand coated surface acoustic wave quartz crystal sensor for organic vapors. Sens Actuators B 92 243-254... 

Y.S. Fung, C.C.W. Wong, J.T.S. Choy, K.L. Sze, Determination of sulphate in water hy flow-injection analysis with electrode-separated piezoelectric quartz crystal sensor, Sens. Actuators 130 (2008) 551-560. 

Cheng TJ, Chang HC, Lin TM. A piezoelectric quartz crystal sensor for the determination of coagulation time in plasma and whole blood. Biosens Bioelectron 1998 13 147-56. 

Chang H-C, Cheng T-J, Wu T-H, Lin T-M. Determination of coagulation time in whole blood containing anticoagulant by piezoelectric quartz crystal sensor. Sens Actuators B Chem 2000 66 296-8. 

Randin, J.P. and Ziilig, F. (1987). Relative humidity measurements using a coated piezoelectric quartz crystal sensor. Sensors Actuators 11 319. 

LE Arenas, B.S. Ebarvia and F.B. Sevilla, Enantioselective piezoelectric quartz crystal sensor for d-methamphetamine based on a molecularly imprinted polymer. Anal. Bioanal. Chem., 397 (7) 3155-3158,2010. 

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