Platinum Nanoparticle Size and Density Impacts Purine Electrochemistry with Fast-Scan Cyclic Voltammetry

We demonstrate the density and shape of platinum nanoparticles (PtNP) on carbon-fiber microelectrodes with fast-scan cyclic voltammetry (FSCV) directly impacts detection of adenosine. Previously, we showed that metal nanoparticle-modified carbon significantly improves adenine-based purine detection; however, how the size and shape of the particles impact electrochemical detection was not investigated. Electrochemical investigations of how the surface topology and morphology impacts detection is necessary for designing ultrasensitive electrodes and for expanding fundamental knowledge of electrode-analyte interactions. To change the density and shape of the PtNP's on the surface, we varied the concentration of K2PtCl6 and electrodeposition time. We show that increasing the concentration of K2PtCl6 increases the density of PtNP's while increasing the electrodeposition time impacts both the density and size. These changes manipulate the adsorption behavior which impacts sensitivity. Based on these results, an optimal electrodeposition procedure was determined to be 1.0 mg ml(-1) of K2PtCl6 deposited for 45 s and this results in an average increase in adenosine detection by 3.5 +/- 0.3-fold. Interestingly, increasing the size and density of PtNPs negatively impacts dopamine detection. Overall, this work provides fundamental insights into the differences between adenosine and dopamine interaction at electrode surfaces.

Automated summary

This study demonstrates that the density and shape of platinum nanoparticles on carbon-fiber microelectrodes directly affect the detection of adenosine. By altering the concentration of K2PtCl6 and the electrodeposition time, the density and size of PtNPs can be manipulated, which in turn affects the adsorption behavior and sensitivity. The research also provides insights into the differences in the interaction between adenosine and dopamine on electrode surfaces.