Use of -cyclodextrin as enhancer of ascorbic acid rejection in permselective films for amperometric biosensor applications
Date
2018Author
Monti P.Rocchitta G.
Marceddu S.
Dettori M.A.
Fabbri D.
Jaoua S.
Migheli Q.
Delogu G.
Serra P.A.
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Interference rejection in amperometric biosensors can be more effective introducing some modifiers during electro-deposition of permselective film. Addition of ?-cyclodextrin (?CD), a cyclic oligosaccharide composed of seven glucose units, to the ortho-phenylendiamine (oPD) monomer were already demonstrated to provide an enhancement in ascorbic acid (AA) rejection. Here we evaluated the improvement in permselectivity of poly-eugenol and poly-magnolol films electro-polymerized in presence of different amounts of ?CD or eugenol-?CD inclusion complex for amperometric biosensor application. Starting from Pt-Ir wire as transducer several microsensors were covered with polymeric films doped with ?CD-based modifiers through constant potential amperometry. Characterization of modified polymers was achieved by scanning electron microscopy and permselectivity analysis. Poly-magnolol film in combination with ?CD showed a worsening in permselectivity compared to poly-magnolol alone. In contrast, the introduction of ?CD-based modifier enhanced the interference rejection toward the archetypal interferent AA, while slightly affecting permeability toward H2O2 compared to the poly-eugenol without modifier. The AA rejection seems to be influenced by the availability of ?CD cavity as well as film performance due to concentration of ?CD-Eugenol inclusion complex. A poly-eugenol film co-polymerized with 2 mM ?CD-eugenol inclusion complex showed a permselectivity equal to poly-orthophenylendiamine film (PPD), with a lower permeability to AA, likely to be related with a self-blocking mechanism. Based on these results, a biosensor for glutamate was constructed with a poly-eugenol doped with ?CD-eugenol as permselective layer and its permselectivity, stability and lifetime were determined. ? 2018
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