An Impedimetric Glucose Biosensor Based on Overoxidized Polypyrrole Thin Film

Abstract

Polypyrrole (pPy) thin films were synthesized electrochemically by a pulse method on platinum electrodes in Nbutyl-N-methyl-pyrrolidinium bis(trifluoromethanesulfonyl)imide ionic liquid (PYR 14 TFSI). An important aspect of this procedure is the use of an ionic liquid, as synthetic medium. Further, it can be used for several procedures and it can then be renewed and recycled by a simple extraction just with warm water. It is therefore possible to remove it from all the residual oxidized pyrrolic compounds and purify the solvent in a very simplicistic way. After the synthesis pPy was overoxidized (opPy ) and the process was followed by EIS (Electrochemical Impedance Spectroscopy). opPy is attractive for the realization of sensors and biosensors because of its good selectivity towards hydrogen peroxide (H 2 O 2 ) with respect to the most common interferents. In particular it can find an application in food process control. The EIS response to hydrogen peroxide and biological interferents indicated opPy as a highly sensitive electrochemical platform for impedimetric sensing. The glucose oxidase enzyme (GOD) was immobilized onto the polymer and the modified electrode was assembled and tested as an impedimetric biosensor. This technique seems very promising for application in food process control.

Multioperational Oxidase Biosensors Based on Carbosilane Dendrimers with Interacting Ferrocenes

“…The principal interfering agents in biological samples, ascorbic acid (AA), uric acid (UA) and p-acetaminophenol (ACE) usually produce a substantial anodic current increase in the steady-state response of sensors, because their electrooxidation occurs at potentials more positive than 0.2 V [18]. The response of the biosensors reported in this work was unaffected by the presence of normal physiological interfering specie concentrations (0.1 mM) for operating potential values between 0.05 and À0.05 V. In fact, the signal due to the addition of 0.1 mM AA, UA and ACE to a 1 mM glucose solution was unappreciable while the applied potential is kept into this range.…”

“…Lactic acidosis is known to accompany decreased tissue oxygenation and drug toxicity, and the analysis of lactate can be used as a preliminary diagnostic for cystic fibrosis, metabolic disorders, thrombosis and physical condition of athletes [15,16]. In addition to the relevance in clinical diagnosis, the determination of glucose and lactate is very important in other areas such as fermentation control and food analysis [17,18].…”

Gold microtubes assembling architecture for an impedimetric glucose biosensing system

“…[19][20] OpPy is de-doped, anions are expelled, and some carbonyl groups are formed in β-position of the pyrrole rings [19][20] but endowed of a superior permselectivity vs. interferents.…”

“…The duration of each pulse was 0.5 seconds for 40 cycles. [20] The overoxidation of pPy after the synthesis was run in potentiostatic conditions at E=+0.8 V vs. Ag/AgCl and in phosphate buffer pH 7.0 until a very low constant current value was reached. [20] …”

“…[20] The electropolymerization of pyrrole 0.1 M in PYR 14 TFSI was carried out at room temperature using a three-electrode glass cell equipped with a Pt counter electrode and a silver pseudo-reference electrode. A Pt disc electrode (0.071 cm 2 apparent area) was used, modified with gold microtubes [21], as the working electrode.…”