Design of molecular wires based on supramolecular structures for application in glucose biosensors

In the present work, the synthesis and the spectroelectrochemical characterization of a novel iron compound derived of tetra-2-pyridyl-1,4-pyrazine (TPPZ) with hexacyanoferrate species forming a very stable supramolecular complex in the presence of polypyrrole (PPY) matrix, is described. The hybrid material has shown excellent catalytic activity towards H2O2 detection that makes it suitable for being used as redox mediator in a glucose biosensor. The hybrid FeTPPZFeCN/PPY film presents satisfactory detection limits and high sensitivity for H2O2 in the presence of K+ or Na+ ions. For the glucose biosensor, a linear range up to 1.1 mmol l−1 of glucose was observed with no interferences. In this case, the sensitivities obtained were 7.88 and 5.90 μA mmol−1 l cm−2 in phosphate buffer or NaCl solutions, respectively. The good sensitivity is related to the presence of a high-dimensional structure based on polypyridine type ligands providing an “electron antennae effect” facilitating electron tunneling between the protein and the electrode.