Electrochemical Evaluation of a Multi-Site Clinical Depth Recording Electrode for Monitoring Cerebral Tissue Oxygen

Abstract

<jats:p>The intracranial measurement of local cerebral tissue oxygen levels—PbtO2—has become a useful tool for the critical care unit to investigate severe trauma and ischemia injury in patients. Our preliminary work in animal models supports the hypothesis that multi-site depth electrode recording of PbtO2 may give surgeons and critical care providers needed information about brain viability and the capacity for better recovery. Here, we present a surface morphology characterization and an electrochemical evaluation of the analytical properties toward oxygen detection of an FDA-approved, commercially available, clinical grade depth recording electrode comprising 12 Pt recording contacts. We found that the surface of the recording sites is composed of a thin film of smooth Pt and that the electrochemical behavior evaluated by cyclic voltammetry in acidic and neutral electrolyte is typical of polycrystalline Pt surface. The smoothness of the Pt surface was further corroborated by determination of the electrochemical active surface, confirming a roughness factor of 0.9. At an optimal working potential of −0.6 V vs. Ag/AgCl, the sensor displayed suitable values of sensitivity and limit of detection for in vivo PbtO2 measurements. Based on the reported catalytical properties of Pt toward the electroreduction reaction of O2, we propose that these probes could be repurposed for multisite monitoring of PbtO2 in vivo in the human brain.</jats:p>

Devices for assessing microcirculation

“…In fact, in the neurocritical field, this type of probes has been coupled to intracranial pressure monitoring allowing continuous PO 2 recording in the human brain. In addition, a recent in vitro study suggested that this probe may allow multisite electrophysiology and standardized electrochemical detection of O 2 , which is promising in multimodal monitoring [18].…”

Applications of flexible electronics related to cardiocerebral vascular system

“…408 Thus, PbtO 2 is treated as a reliable marker of CBF and cerebral ischemia under certain conditions. The current clinical methods used to monitor PbtO 2 include invasive techniques such as Clark electrode-based electrochemical sensing and fluorescence quenching-based optical sensing [ 49 ], also the non-invasive techniques like NIRS [ 426 , 427 ]. The basic device of an electrochemical PO 2 sensor designed for medicine was first proposed by Leland Clark in 1956 [ 106 ].…”

Editorial on the Special Issue on Microelectrode Arrays and Application to Medical Devices

“…Among those, the amperometric sensing technique allows real-time monitoring of brain oxygenation and can be an effective bedside method for the detection of cerebral ischemia. Due to the electrocatalytic behavior of Pt, Ledo et al reported the potential application of those commercially available intracranial recording electrodes that include a thin Pt film on their recording sites, for amperometric monitoring of PbtO 2 [ 5 ]. They conducted a surface morphology characterization and an electrochemical evaluation of the performance of such a device for oxygen detection and concluded that these probes can be repurposed for in vivo multisite monitoring of PbtO 2 .…”

“…In this editorial note, we briefly review the major findings of the 10 articles published in the Special Issue on microelectrode arrays and application to medical devices. The articles are categorized into three sections, i.e., fabrication techniques [ 1 , 2 , 3 , 4 ], application demonstration [ 5 , 6 , 7 , 8 ], and review of recent advances in this field [ 9 , 10 ].…”