Anthraquinone-based sensor

Thioureas-binding site can be introduced to molecules like anthraquinone and is for use in various kinds of anion or fluoride sensors. Thiourea-based sensor are generally designed to recognize anion through an intermolecular hydrogen bonding.167 171... 

Matsue et al. [27] were the first to explore an enzyme-based OECT biosensor. They used Diaphorase as the entrapped enzyme in a polypyrrole transducing layer for the detection of NADH via a redox mediator (the sodium salt of anthraquinone-2-sulfonic acid). The net result was the conversion of polypyrrole from its conducting state to its insulating state in the presence of NADH. The device showed a response time of 15--20 min in the presence of NADH. Later Nishizawa et al. [26] exploited the pH sensitivity of the polypyrrole film for the design and fabrication of OECT sensors for pH and for pencillin. The Penicillinase enzyme was entrapped in a membrane which was coated with a polypyrrole film, in which a decrease in pH was observed in the presence of penicillin due to the hydrolysis of penicillin by Penicillinase. 

McGilvray K, Chretien M, Lukeman M and Scaiano J (2006), Simple and smart oxygen sensor based on the intrazeolite reactions of a substituted anthraquinone , Chem Commun, 42,4401-4403. 

---