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A new layer-by-layer supramolecular approach for the construction of self-assembled nanoarchitectures of polyamidoamine (PAMAM) dendrimers and peroxidase on gold surface is reported. The methodology is based on the supramolecular self-assembly of alternated layers of adamantane-modified horseradish peroxidase and β-cyclodextrin-branched PAMAM G-5 dendrimers on a gold electrode, previously coated with β-cyclodextrin-modified cysteamine core PAMAM G-4 dendron. The formation of layer-by-layer assemblies (up to three dendrimer/peroxidase bilayers) was studied by SPR, quartz crystal microbalance, AFM and cyclic voltammetry. The analytical applicability of these architectures was evaluated by constructing a H 2 O 2 biosensor. The electroanalytical response of the biosensor towards H 2 O 2 increased with the number of enzyme layers. The bioelectrode constructed with three enzyme layers showed a low detection limit of 160 nM, a sensitivity of 602 μA/M cm 2 and retained 63% of its initial activity after 30 days of storage in wet conditions.

Gold electrodes were functionalized with an electropolymerized matrix of Au nanoparticles modified with 2-mercaptoethanesulfonic acid, 3-mercaptophenyl boronic acid and p -aminothiophenol. The resulting nanostructured electroconductive matrix was used as support for the oriented immobilization of horseradish peroxidase to construct a reagentless amperometric biosensor for H 2 O 2 . The electrode, poised at 0.0 mV, exhibited a rapid response within 8 s and a linear calibration range from 5 μM to 1.1 mM H 2 O 2 . The sensitivity of the biosensor was determined as 498 μA/M cm 2 , and its detection limit was 1.5 μM H 2 O 2 at a signal-to-noise ratio of 3. The electrode retained 95% and 72% of its initial activity after 21 and 40 days of storage at 4 °C.