The realization and the study of modified electrodes is very important to develop the next generation of biosensors. For this purpose, the unique optical and conductivity properties of gold nanoparticles make them very interesting for the construction of nanoparticles-based devices. Gold nanoparticles can act as nanoscale relays which allow the electrochemical communication between redox proteins and the bulk electrode material. Gold is a material perfectly biocompatible, and this characteristic makes it suitable to be used in many biological application fields. Gold colloidal nanoparticles were synthesized by HAuCl4 chemical reduction directly in aqueous solution, using only PVP as reducing-surfacting agent. Varying the Au -PVP molar ratio, we were able to obtain gold nanoparticles of different size and shape. The morphology and the distribution of the gold nanoparticles both in solution and on the electrode surface were studied by AFM and TEM. The modified electrode was made by dip coating technique, putting a conventional glassy carbon electrode (GCE) into a solution containing gold nanoparticles stabilized by PVP. The gold nanoparticles used in this study have diameters ranging from 9 to 50 nm. This modified gold electrode was used for the determination of different neurotransmitters, such as dopamine, caffeic acid, epinephrine and norepinephrine, using amperometric and cyclic voltammetry techniques. The electrochemical response was studied in function of the nanoparticles dimension and of deposition time. The results have shown that using a gold nanoparticles modified GCE, an amplification of electrochemical signals of the neurotransmitters was obtained with respect to the conventional GCE. Moreover, we have found that the responses are stable during time and no degradations are present even after several days. A study on the electron transfer between neurotransmitters and electron surface was also carried out by means of impedance measurements.
Gold nanoparticles modified GC electrode for the determination of neurotransmitters: influence of nanoparticles size on the electrochemical response
A Curulli;
2007
Abstract
The realization and the study of modified electrodes is very important to develop the next generation of biosensors. For this purpose, the unique optical and conductivity properties of gold nanoparticles make them very interesting for the construction of nanoparticles-based devices. Gold nanoparticles can act as nanoscale relays which allow the electrochemical communication between redox proteins and the bulk electrode material. Gold is a material perfectly biocompatible, and this characteristic makes it suitable to be used in many biological application fields. Gold colloidal nanoparticles were synthesized by HAuCl4 chemical reduction directly in aqueous solution, using only PVP as reducing-surfacting agent. Varying the Au -PVP molar ratio, we were able to obtain gold nanoparticles of different size and shape. The morphology and the distribution of the gold nanoparticles both in solution and on the electrode surface were studied by AFM and TEM. The modified electrode was made by dip coating technique, putting a conventional glassy carbon electrode (GCE) into a solution containing gold nanoparticles stabilized by PVP. The gold nanoparticles used in this study have diameters ranging from 9 to 50 nm. This modified gold electrode was used for the determination of different neurotransmitters, such as dopamine, caffeic acid, epinephrine and norepinephrine, using amperometric and cyclic voltammetry techniques. The electrochemical response was studied in function of the nanoparticles dimension and of deposition time. The results have shown that using a gold nanoparticles modified GCE, an amplification of electrochemical signals of the neurotransmitters was obtained with respect to the conventional GCE. Moreover, we have found that the responses are stable during time and no degradations are present even after several days. A study on the electron transfer between neurotransmitters and electron surface was also carried out by means of impedance measurements.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
