Pyrrole (Py) and pyrrole derivative with carboxyl groups

1\|(2\|carboxyethyl)pyrrole (PyCA)

were copolymerized with 6-(1H-pyrrol-1-yl)hexane-l-thiol(PHT) self-assembled on Au surface by chemical polymerization to form a layer of the copolymer film

(poly(PHT-co-Py-co-PyCA)).The carboxyl groups of (poly(PHT-co-Py-co-PyCA)) were activated using N-(3-dimethylaminopropyl)-N-ethylcarbodilimide (EDC) and N-hydroxysuccinimide (NHS) and transferred to amide bonds by reacting with the amino groups in the amino-labeled probe DNA.In consequence

amino-labeled DNA could be immobilized onto the copolymer.Afterwards

the complementary target DNA can be hybridized with probe DNA.The chemical structure and components of poly(PHT-co-Py-coPyCA) before and after DNA immobilization were investigated by Fourier-transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS).The electrochemistry properties and the variation of the charges of copolymer film before and after DNA anchor were characterized by cyclic voltammetry and electrochemical impedance spectra.To detect the immobilization behavior of DNA

surface plasma resonance was used.The result revealed that it is a slow process for DNA anchoring onto the copolymer matrix and the electrochemical activity and the charges transfer decreased after DNA immobilization/hybridization.Furthermore

there is no non-specific adsorption between target DNA and copolymer.It could supply the theoretical and experimental base for the application of copolypyrrole film functionalized with carboxyl groups as DNA sensors.