A platinum oxide-based microvoltammetric pH electrode suitable for physiological investigations

Area of Science:

• Electrochemistry
• Biomedical Engineering
• Materials Science

Background:

• Miniaturized pH electrodes are crucial for in vivo monitoring.
• Continuous real-time pH measurements can predict metabolic events and improve patient prognosis.

Purpose of the Study:

• To investigate the in vitro performance of a platinum oxide-based microvoltammetric pH electrode for in vivo applications.
• To assess the pH-dependent responses and stability of the electrode with an integrated pseudo reference electrode.

Main Methods:

• Electrochemical characterization of a Pt oxide-based microelectrode.
• Cyclic voltammetry within a -0.65 V to +0.8 V potential window.
• Evaluation of pH-dependent redox peaks (monolayer oxide and hydrogen adsorption/desorption) with an Ag/AgCl pseudo reference electrode.
• Preliminary in vivo recording in a mouse striatum.

Main Results:

• The electrode exhibited pH-dependent linear responses for hydrogen desorption (49 ± 11 mV/pH) and monolayer oxide reduction (76 ± 4 mV/pH) after HCl pre-activation.
• The integrated Ag/AgCl pseudo reference electrode showed near-Nernstian (58 ± 5 mV/pH) and sub-Nernstian (43 ± 6 mV/pH) behavior for the respective peaks.
• A preliminary in vivo recording confirmed the stability of the monolayer oxide reduction peak under physiological conditions.

Conclusions:

• The Pt oxide-based pH electrode is capable of stable, continuous in vivo recordings.
• Further characterization is warranted to optimize the electrode for clinical applications.
• This technology holds promise for improved patient monitoring and prognosis.