7^th Euro Biosensors & Bioelectronics Congress

Biography

Biography: Siddheswar Maikap

Abstract

Quantification of pH/H₂O₂ attracts a lot of attentions due to its importance in chemical industries as well as biomedical diagnostic. For the detection of pH and H₂O₂ by using electrolyte-insulator-semiconductor (EIS) is preferred due to label-free detection, easy fabrication process, and low cost. The NiO_x based sensor has shown good pH sensitivity of 50.25 mV/pH. X-ray photo-electron spectroscopy of Ni 2p_3/2 has shown two different oxidation states of NiO_x membrane and those are Ni²⁺ and Ni³⁺ having binding energy 854.5 eV and 856.5 eV, respectively. Existence of these two oxidation states resembles the reduction-oxidation (redox) characteristics of NiO_x membrane toward the electroactive species like H₂O₂. A reference voltage shift of 41 mV is obtained for H₂O₂ concentration of 10 µM and has shown good linearity up to 100 µM for the first time. In addition, the IrO_x membrane shows a record pH sensitivity of 150.4 mV/pH for the first time. This IrO_x sensor demonstrated good catalytic behavior as well as the breast cancer biomarker LOXL2 with a concentration of approximately 150 nM is detected. This IrO_x nano-net sensor demonstrates good catalytic behavior for H₂O₂ reduction with a concentration of 100 fM because the oxidation state changes from Ir³⁺ to Ir⁴⁺, whereas a pure SiO₂ membrane could not sense H₂O₂. The oxidation states are confirmed by X-ray photo-electron spectroscopy (XPS). Similarly, prostate cancer is also detected by using NiO_x membrane. Therefore, good pH response and redox characteristics of the IrO_x/NiO_x sensing membrane allow it to diagnosis human disease in future.