RESUMEN
A system device using multifunctional conjugated copolymer poly(5-hydroxy-1,4-naphthoquinone-co-hydroxy-2-thioacetic acid-1,4-naphthoquinone) acting both as immobilizing and transducing element for reagentless immunosensor has been constructed. Its functionality was evaluated in an antigen-antibody interaction model using ovalbumin-anti-ovalbumin. It was shown that the system specifically detects via electrochemical signal the antigen-antibody immune interaction in a reagentless context. Comparison to the conventional ELISA technique relevant to performance and sensitivity was presented.
Asunto(s)
Técnicas Biosensibles/métodos , Polímeros/química , Suero/química , Ácido Acético/química , Técnicas Biosensibles/instrumentación , Electroquímica , Enzimas Inmovilizadas/química , Naftoquinonas/química , Estándares de Referencia , Compuestos de Sulfhidrilo/química , Factores de TiempoRESUMEN
An electrochemical hybridization biosensor based on peptide nucleic acid (PNA) probe is presented. PNA were attached covalently onto a quinone-based electroactive polymer. Changes in flexibility of the PNA probe strand upon hybridization generates electrochemical changes at the polymer-solution interface. A reagentless and direct electrochemical detection was obtained by detection of the electrochemical changes using square wave voltammetry (SWV). An increase in the peak current of quinone was observed upon hybridization of probe on the target, whereas no change is observed with non-complementary sequence. In addition, the biosensor is highly selective to effectively discriminate a single mismatch on the target sequence. The sensitivity is also presented and discussed.
Asunto(s)
Técnicas Biosensibles/instrumentación , ADN/metabolismo , Conductividad Eléctrica , Sondas de Oligonucleótidos/metabolismo , Ácidos Nucleicos de Péptidos/metabolismo , Polímeros/química , Secuencia de Bases , ADN/genética , Electroquímica , Electrodos , Equipo Reutilizado , Hibridación de Ácido Nucleico , Sondas de Oligonucleótidos/química , Sondas de Oligonucleótidos/genética , Ácidos Nucleicos de Péptidos/química , Quinonas/química , Coloración y Etiquetado , Agua/químicaRESUMEN
We have constructed a reagentless lactate sensor using lactate oxidase (LOD) covalently attached to an electropolymerized copolymer film, poly(5-hydroxy-1,4-naphthoquinone-co-5-hydroxy-3-thioacetic acid-1,4-naphthoquinone), poly(JUG-co-JUGA). Around 10(-12)Mcm(-2) of covalently bound enzymes are immobilized on these films. In aerated medium, the amperometric response versus lactate concentration shows a sensitivity of 350 +/- 50 microAM(-1)cm(-2) for an applied potential of +0.5V versus Ag|AgCl on a film-coated Pt electrode. In deaerated medium, the quinone group, conjugated with the polymer backbone, acts as an immobilized mediator. An amperometric response is observed on film-coated glassy carbon (GC) electrode at a potential as low as -0.1V versus Ag|AgCl, with a sensitivity of 110 +/- 40 microAM(-1)cm(-2).