The formation of nanofilm deposits of TiO2 nanoparticle phytates based on the directed assembly methodology [1] is demonstrated. Alternant exposure of a tin-doped indium oxide (ITO) or gold electrode surface to aqueous solutions of TiO2 nanoparticles (3-4 % in HNO3, ca. 6 nm diameter) and phytic acid (40 mM, at pH=3) causes layer-by-layer growth of a three dimensional mesoporous structure.
Cytochrome c in aqueous phosphate buffer (pH=7) is readily accumulated into the mesoporous TiO2 phytate film predominantly due to electrostatic binding of the positively charged protein to the negatively charged interfacial phytic acid [2]. Voltammetric data for the reversible reduction and re-oxidation of cytochrome c suggest strong adsorption and ideal thin film behaviour over a wide range of conditions. Voltammetric and quartz crystal microbalance data are presented for accumulation and electrochemically driven desorption of Ru(NH3)63+ [3].
1. K. J. McKenzie, F. Marken, M. Hyde, R.G. Compton,
New J. Chem., 26, (2002), 625.
2. K. J. McKenzie, F. Marken, Langmuir, 19, (2003), 4327.
3. K. J. McKenzie, F. Marken, X. Gao, S. C. Tsang, K.Y. Tam, Electrochem.
Commun., 5, (2003), 286.
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