An ultrosensitive biosensor based on electroactive nanoparticles self-assembled from 3-thiophenecarboxylic acid-modified starch

A kind of electroactive nanoparticles (NPs) was prepared in solution by self-assembling amphiphilic 3-thiophenecarboxylic acid-modified starch (TPCA-St), which was synthesized through esterification reaction. By casting TPCA-St NPs on the surface of gold electrode and subsequent electropolymerization of the thiophene moieties in NP film, the electroconductive TPCA-St NP-based film was formed. After horseradish peroxidase and Nafion were sequentially cast on the film surface, a biosensor was successfully prepared. The prepared biosensor showed high sensitivity for H 2 O 2 detection. The linear range from 1 × 10 −10 to 1 × 10 −5  mol L −1 with a detection limit of 3 × 10 −11  mol L −1 was obtained for H 2 O 2 sensing. The biosensor also showed good repeatability and stability, and it has been successfully used to sense H 2 O 2 in commercial disinfector with satisfactory results.