Piezoelectric affinity sensors for cocaine and cholinesterase inhibitors
| Authors | |
|---|---|
| Year of publication | 2005 |
| Type | Article in Periodical |
| Magazine / Source | Talanta |
| MU Faculty or unit | |
| Citation | |
| Web | http://dx.doi.org/10.1016/j.talanta.2004.07.008 |
| Field | Biochemistry |
| Keywords | piezoelectric sensory; enzyme inhibition; |
| Description | We report here the development of piezoelectric affinity sensors for cocaine and cholinesterase inhibitors based on the formation of affinity complexes between an immobilized cocaine derivative and an anti-cocaine antibody or cholinesterase. For both binding reactions benzoylecgonine-1,8-diamino-3,4-dioxaoctane (BZE-DADOO) was immobilized on the surface of the sensor. For immobilization, pre-conjugated BZE-DADOO with 11-mercaptomonoundecanoic acid (MUA) via 2-(5-norbornen-2,3-dicarboximide)-1,1,3,3-tetramethyluronium-tetrafluoroborate (TNTU) allowed the formation of a chemisorbed monolayer on the piezosensor surface. The detection of cocaine was based on a competitive assay. The change of frequency measured after 300 s of the binding reaction was used as the signal. The maximum binding of the antibody resulted in a frequency decrease of 35 Hz (with an imprecision 3%, n = 3) while the presence of 100 pmol l1 cocaine decreased the binding by 11%. The limit of detection was consequently below 100 pmol l1 for cocaine. The total time of one analysis was 15 min. This BZE-DADOO-modified sensor was adapted for the detection of organophosphates. BZE-DADOO a competitive inhibitor served as binding element for cholinesterase in a competitive assay. |
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