Influence of ultrasound irradiation on the adsorption of bovine serum albumin on copper
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The effect of irradiation by power ultrasound on the adsorption of proteins on copper has been investigated, using bovine serum albumin (BSA) as a model protein in pH 7 phosphate buffer solution. Open circuit potential measurements, cyclic voltammetry and electrochemical impedance spectroscopy were used to characterise the copper/solution interface. Electrochemical impedance measurements at potentials close to the open circuit potential showed that pulsed ultrasound irradiation removes the naturally formed copper oxide films in phosphate buffer solution, and that their re-formation can lead to an oxide film with different electrical characteristics. Adsorption of BSA blocks the surface, decreasing or increasing the interfacial resistance, depending on the applied potential and the oxide characteristics, as well as changing the interfacial capacitance. This study augurs well for application of the combination of electrochemical impedance plus ultrasound to other systems.
KeywordsUltrasound irradiation Power ultrasound Copper Bovine serum albumin Electrochemical impedance spectroscopy
The authors acknowledge financial support from EU-Alfa project PETRA II (ALFA_II-0343-FA-FCD-FI), from Fundação para a Ciência e Tecnologia (FCT), Portugal for a PhD grant (SFRH/BD/31483/2006) for E.M.P., from ICEMS/FCT, Research Unit 103, Coimbra-Portugal and Instituto de Física Gleb Wataghin, Campinas-Brazil.
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