Iridium Oxide Enabled Sensors Applications

Abstract

There have been numerous studies applying iridium oxides in different applications to explore their proton-change-based reactions since the 1980s. Iridium oxide can be fabricated directly by applying electrodeposition, sputter-coating method, or oxidation of iridium wire. Generally, there have been currently two approaches in applying iridium oxide to enable its sensing applications. One was to improve or create different electrolytes with (non-)electrodeposition method for better performance of Nernst Constant with the temperature-related system. The mechanism behind the scenes were summarized herein. The other was to change the structure of iridium oxide through different kinds of templates such as photolithography patterns, or template-assisted direct growth methods, etc. to improve the sensing performance. The detection targets varied widely from intracellular cell pH, glucose in an artificial sample or actual urine sample, and the hydrogen peroxide, glutamate or organophosphate pesticides, metal-ions, etc. This review paper has focused on the mechanism of electrodeposition of iridium oxide in aqueous conditions and the sensing applications towards different biomolecules compounds. Finally, we summarize future trends on Iridium oxide based sensing and predict future work that could be further explored.

Nafion Modified Titanium Nitride pH Sensor for Future Biomedical Applications

“…Metal oxide pH electrodes were once an alternative to glass pH electrodes [ 11 , 12 , 13 , 14 ]. IrO 2 -based pH electrodes and their less popular RuO 2 -based counterparts have both been the subject of extensive research [ 12 ]. Metal oxides’ primary flaw is their redox sensitivity [ 15 ].…”

A Comparative Study on the Effect of Substrate Structure on Electrochemical Performance and Stability of Electrodeposited Platinum and Iridium Oxide Coatings for Neural Electrodes

“…Stable nanoPt and IrO x coatings not only improve neural electrical stimulation and recording performance, but also have the potential for in vivo neurobiochemical detection. The nanoPt coatings on the surface of the hierarchical Pt-Ir substrate significantly increase the electrochemical active area, which could be used for the non-enzymatic detection of glucose [ 17 , 43 ], hydrogen peroxide [ 44 ], and dissolved oxygen [ 44 , 45 ]. In addition, an IrO x coating is being considered as a reference electrode candidate for in vivo biosensing due to its biocompatibility [ 46 ].…”

Nanostructured Iridium Oxide: State of the Art

“…Moreover, IrO 2 -based electrodes could be used in many application fields, since their pH response is not affected by most anions present in environmental systems, such as Na + , K + , Li + , Mg 2+ , Ca 2+ , Cl − , Br − , NO 3 − , nor by the main complexing agents present in biological systems, such as citrate, lactate and phosphate [53]. For these reasons, IrO 2 has been widely employed for the sensing of glucose, hydrogen peroxide, glutamate, metal ions, organophosphates, and pesticides [55]. Furthermore, the Food and Drug Administration approved IrO 2 as a high biocompatible material, facilitating its application in biosensors [56,57], probe for fluorescence imaging [58], photodynamic/photothermal therapy [59], and stimulating and recording electrodes [60,61].…”