Fabrication, characterization and modeling of nano-structured Pt electrodes for electrochemical biosensors.

The increasing demand for reliable and non-invasive devices for biomedical applications has driven the research toward the development of low-power nano-scaled electronic devices capable of performing amperometric measurements of glucose concentration for diabetic patients. However, the state of the art of three-electrodes electrochemical cells used as sensors are based on immobilized enzymes that require specific environmental conditions. Moreover, these devices represent systems that involve the integration of different domains of physics, the electrical and the electrochemical ones, requiring a precise transposition of the electrochemical behavior of the cell in the electrical domain to perform the simulations needed in the design process. In this study, nano-structured platinum electrodes for the non-enzymatic sensing of glucose are fabricated and characterized. The nano-structures were made by means of an electrodeposition process, which was performed in one-step to obtain nano-spheres or nano-petals-like structures and in two-steps to obtain nano-petals onto nano-spheres-like structures to further increase the electro-active area of the electrode. The resulting structures were observed exploiting the ZEISS Supra 40 Field Emission Scanning Electron Microscopy and the characterization was carried out in Phosphate Buffer Saline (PBS) performing CycloVoltammetry (CV), Square Wave Voltammetry (SWV) and ChronoAmperometry (CA) on Metrohm Autolab PGSTAT128 potentiostat. The repeatability of the process was assessed, as well as the increase in electro-active area due to the presence of the nano-structures. The correct detection of the glucose peaks without immobilized enzymes was verified for different values of glucose concentrations in the physiological range. Finally, the resulting measurements were employed to build a reliable parametric model replicating the system's effective behaviour.