Spatial organization of peptide nanotubes for electrochemical devices

• Published in: Journal of materials science Vol. 45; no. 18; pp. 5101 - 5108
• Main Authors: Cipriano, T. C., Takahashi, P. M., de Lima, D., Oliveira, V. X., Souza, J. A., Martinho, H., Alves, W. A.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01-09-2010; Springer; Springer Nature B.V
• Subjects: Biosensors; Buffer solutions; Characterization and Evaluation of Materials; Chemical properties; Chemistry and Materials Science; Classical Mechanics; Crystallography and Scattering Methods; Devices; Electric properties; Electrodes; Electron transfer; Electron transport; Hydrogen peroxide; Icam 2009; Indium tin oxide; Materials Science; Nanotubes; Oxidation; Peptides; Polyelectrolytes; Polymer Sciences; Self assembly; Signal to noise ratio; Solid Mechanics; Hybrid Film; MP11 Concentration; Direct Electron Transfer; Heme Protein; Allylamine Hydrochloride
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-010-4478-4

A novel biosensor for hydrogen peroxide was developed by combining the known properties of microperoxidase-11 (MP11) as an oxidation catalyst, and the interesting properties of diphenylalanine peptide nanotubes (PNTs) as a supporting matrix to allow a good bioelectrochemical interface. In this case, the synthesized MP11/PNTs were immobilized onto the ITO electrode surface via layer-by-layer (LBL) deposition, using poly(allylamine hydrochloride) (PAH) as positively charged polyelectrolyte layers. The PNTs provide a favorable microenvironment for MP11 to perform direct electron transfer to the electrode surface. The resulting electrodes showed a pair of well-defined redox peaks with formal potential at about −343 mV (versus SCE) in phosphate buffer solution (pH 7). The experimental results also demonstrated that the resulting biosensor exhibited good electrocatalytic activity to the reduction of H
2
O
2
with a sensitivity of 9.43 μA cm
−2
 mmol
−1
 L, and a detection limit of 6 μmol L
−1
at the signal-to-noise ratio of 3. Moreover, we also observed that the peptides self-assembly can be influenced upon changing the pH of the solution. Alkaline solution appears to favor the packing of diphenylalanine nanotubes being closer than acidic or neutral conditions. The study proved that the combination of PNTs with MP11 is able to open new opportunities for the design of enzymatic biosensors with potential applications in practice.