Aptameric Enzyme Subunit

TABLE 6.2 Comparison of Detection with B/F Separation and Homogeneous Detection 

Simplicity Fair (it depends on the separation method) Excellent 

Sensitivity Excellent (the noise can be reduced) Good (the signal can be amplified using enzymes) 

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Yoshida W, Mochizuki E, Takase M, Hasegawa H, Morita Y, Yamazaki H, Sode K, Ikebukuro K (2009) Selection of DNA aptamers against insulin and construction of an aptameric enzyme subunit for insulin sensing. Biosens Bioelectron 24(5) 1116-1120... 

To demonstrate a way of the use of aptamers in design of biomimetic sensors, two examples will be cited from the recent literature. The piezoelectric sensor for protein IgE has been developed with the use of commercially available anti-IgE aptamer oligonucleotide.167 The obtained sensor shows specificity and sensitivity equivalent to these of immunosensor, but for aptamer-based sensor a less decrease of sensitivity after consecutive cycles of analyte binding and regeneration, as well as relative heat resistance and stability over several weeks was shown. A more complex mechanism of sensing was employed in adenosine aptamer-based sensor.168 Detection was based on enzymatic activity measurements by fluorescence polarization with the use of aptameric enzyme subunit, which was a DNA aptamer composed of enzyme-inhibiting aptamer and adenosine-binding aptamer. 

Yoshida, W. Sode, K. Ikebukuro, K., Aptameric enzyme subunit for biosensing based on enzymatic activity measurement, Anal. Chem. 2006, 78, 3296-3303... 

BIOSENSORS USING THE APTAMERIC ENZYME SUBUNIT THE USE OF APTAMERS IN THE ALLOSTERIC CONTROL OF ENZYMES... 

These signaling aptamers have shown that multiple aptamer ligands can be detected without bound-free separation that is, through homogeneous detection. It is very difficult to realize this type of detection using antibodies, aside from a few exceptions (Ueda et al., 2003). We discuss the problem of homogeneous detection in the next section and introduce our solution the aptameric enzyme subunit. 

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