Electrochemical Biosensitivity of Titania Nanotubes towards Alkaline Phosphatase, IL-6 and IL-8 Interleukins Biomarkers

• Published in: Journal of the Electrochemical Society Vol. 161; no. 14; pp. B275 - B282
• Main Authors: Roman, Ioan, Soare, Maria-Laura, Trusca, Roxana Doina, Fratila, Corneliu, Krasicka-Cydzik, Elzbieta, Stan, Miruna-Silvia, Dinischiotu, Anca
• Format: Journal Article
• Language: English
• Published: The Electrochemical Society 01.01.2014
• ISSN: 0013-4651; 1945-7111
• DOI: 10.1149/2.0071414jes

The paper proposes a new method for direct measurement of human alkaline phosphatase (ALP) and interleukin-6 and -8 (IL-6, IL-8) content using titania nanotubes (TNT) film as sensitive electrode. Under polarization, the interface characteristics are modified by the specific adhesion of proteins to the electrode surface, as shown by confocal fluorescence microscopy, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) investigations for all 3 biomarkers. These changes can be measured by electrochemical impedance spectroscopy (EIS). A thin and uniform gold plating is beneficial for electrochemical sensitivity toward the investigated biomarkers. This electrode reflects the low levels of human ALP in water and in dilute solutions of human serum (HS) and total protein extract (TPE) by EIS. Good calibrations were obtained for the enzyme activities of 50, 100 and 125 U/L, which go below the detection limit obtained by classical methods. Calibration of IL-6 was performed in the concentration range of 0.165 ÷ 1.645 nM. The paper demonstrates that the annealed and in vacuum gold plated TNT/Ti electrode with 50 nm diameter is a new and credible candidate for a highly stable sensor to be used in the human ALP and IL-6 direct determination.