Electroanalytical properties of haemoglobin in silica-nanocomposite films electrogenerated on pyrolitic graphite electrode
ABSTRACT Haemoglobin (Hb) modified electrochemical devices have been prepared by Hb encapsulation in silica sol-gel films (SiO2), which were generated by electro-assisted deposition onto pyrolitic graphite electrodes (PGEs). The stability and electrocatalytic activity of Hb entrapped into SiO2 network was substantially enhanced in the presence of cationic surfactant (CTAB) and Au nanoparticles (Au-NPs). The composition of sol-gel synthesis medium, i.e., molar ratio of silica precursor to water, contents of Hb, CTAB and Au-NPs, as well as the conditions of electrogeneration had a great influence on the electrocatalytic activity of Hb on PGE surface. The electrochemical response of the PGE modified with the composite SiO2-Hb-CTAB-Au-NPs film was found to vary linearly with the concentration of dissolved oxygen in solution and this was exploited to determine this analyte in the tap water with detection limit 0.12 mg L-1. The electrocatalytic current of dissolved oxygen was also found to decrease in the presence of the antivirus drug--amino derivative of adamantane (rimantadine)--which opens the way to the determination of this drug with detection limit 0.3 mg L-1 using PGE modified with SiO2-Hb-CTAB-Au-NPs nanocomposite film.
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Article: Scanning electrochemical microscopy.[show abstract] [hide abstract]
ABSTRACT: This review describes work done in scanning electrochemical microscopy (SECM) since 2000 with an emphasis on new applications and important trends, such as nanometer-sized tips. SECM has been adapted to investigate charge transport across liquid/liquid interfaces and to probe charge transport in thin films and membranes. It has been used in biological systems like single cells to study ion transport in channels, as well as cellular and enzyme activity. It is also a powerful and useful tool for the evaluation of the electrocatalytic activities of different materials for useful reactions, such as oxygen reduction and hydrogen oxidation. SECM has also been used as an electrochemical tool for studies of the local properties and reactivity of a wide variety of materials, including metals, insulators, and semiconductors. Finally, SECM has been combined with several other nonelectrochemical techniques, such as atomic force microscopy, to enhance and complement the information available from SECM alone.Annual Review of Analytical Chemistry (2008) 01/2008; 1:95-131. · 8.60 Impact Factor