Heme proteins sequestered in silica sol–gels using surfactants feature direct electron transfer and peroxidase activity

• Published in: Electrochemistry communications 2004-02, Vol.6 (2), p.205-209
• Main Authors: Nadzhafova, Oksana Yu, Zaitsev, Vladimir N, Drozdova, Marie V, Vaze, Abhay, Rusling, James F
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Biosensors; Biotechnology; Fundamental and applied biological sciences. Psychology; Hemoglobin; Hydrogen peroxide; Methods. Procedures. Technologies; Myoglobin; Sensor; Silica; Sol–gel; Various methods and equipments
• ISSN: 1388-2481; 1873-1902
• DOI: 10.1016/j.elecom.2003.11.013

Hemoglobin (Hb) and myoglobin (Mb) were incorporated into a porous silica network by a sol–gel method using tetraethoxysilane as precursor and cetyltrimethylammonium bromide (CTAB), poly(styrene sulfonate) (PSS) and Nafion as template additives. Three types of composite films were made on glass and pyrolytic graphite (PG) surfaces: silica–CTAB with Mb or Hb (SG-I); silica–CTAB–PSS with Mb (SG-II-Mb); and silica–CTAB–Nafion with Mb (SG-III-Mb). Cyclic voltammetry demonstrated that films with encapsulated protein exchange electrons directly with PG electrodes and have catalytic activity for reduction of oxygen and hydrogen peroxide. Surface areas studies suggest that CTAB can be removed selectively from the films. Catalytic efficiency of SG-I-Mb increased with increasing CTAB content in the initial sol. The SG-II-Mb film was more stable in aqueous propanol-CTAB and 2 mM hydrogen peroxide compared to SG-I-Mb (or Hb) and SG-III-Mb films. SG-II-Mb films on PG electrodes detected hydrogen peroxide by voltammetry with linear calibration in the range 2–30 μM, and detection limit ∼1.5 μM.