Facile Ratiometric Electrochemical Sensor for In Vivo/Online Repetitive Measurements of Cerebral Ascorbic Acid in Brain Microdiaysate

Abstract

The in vivo monitoring of ascorbic acid (AA) following physiological and pathological events is of great importance because AA plays a critical role in brain functions. The conventional electrochemical sensors (ECSs) usually suffered from poor selectivity and sluggish electron transfer kinetics for cerebral AA oxidation. The exploitation of ECSs adapt to the electrochemical detection (ECD)–microdialysis system, here we reported a facile ratiometric electrochemical sensor (RECS) for in vivo/online repetitive measurements of cerebral AA in brain microdiaysate. The sensor were constructed by careful electrodeposition of graphene oxide (GO) onto glassy carbon (GC) electrodes. Methylene blue (MB) was electrostatically adsorbed onto the GO surface as a built-in reference to achieve ratiometric detection of AA. The subsequent proper electroreduction treatment was able to readily facilitate the oxidation of AA at a relatively negative potential (−100 mV) and the oxidation of MB at separated potential (−428 mV). The in vitro experiments demonstrated that the RECS exhibited high sensitivity (detection limit: 10 nM), selectivity, and stability toward AA determination, enabling the in vivo/online repetitive measurement of cerebral AA in brain microdiaysate with high reliability. As a result, the designed RECS was successfully applied in the ECD–microdialysis system to in vivo/online repetitive monitoring the dynamic change of cerebral AA in the progress of the global cerebral ischemia/reperfusion events. More, the microinjection of endogenous AA and AA oxidase (AAOx) verified the reliability of the proposed RECS for in vivo/online repetitive cerebral AA detection. This proposed sensor filled the gap that no rational electrochemical sensor has been developed for the ECD–microdialysis system since its creation by the Mao group in 2005, which provided a reliable and effective method for brain chemistry research.

Redox Host–Guest Nanosensors Installed with DNA Gatekeepers for Immobilization‐Free and Ratiometric Electrochemical Detection of miRNA

“…For ratiometric host–guest assemblies, possible signal crosstalking of dual host and guest redox reporters should be taken into consideration. [ 32 ] Thus, three types of common E m including ferrocene (Fc), methylene blue (MB), and calcein (CA) were selected as guests for investigation ( Figure a). As shown in Figure 4b, the oxidation potential of Fc sample (at 0.2 V vs Ag/AgCl) overlapped with some part of MPDA oxidation potential, while for MB/CA sample, it was ‐0.2 V/0.85 V, which deftly avoided the crosstalk of MPDA (0.34 V)/MPDA–NIR (0.27 V).…”

Facile Electrochemical Microbiosensor Based on In Situ Self-Assembly of Ag Nanoparticles Coated on Ti3C2Tx for In Vivo Measurements of Chloride Ions in the PD Mouse Brain

“…First, graphene oxide (GO) and Ti 3 C 2 T x flakes were synthesized according to our previous reports. , Atomic force microscopy (AFM) images revealed that Ti 3 C 2 T x were 2D rigid flakes (size: 100–250 nm, thickness: ∼1.5 nm) (Figure S1). Then, a bare CFME was prepared and cleaned (see the Supporting Information), and immersed in the above prepared GO suspension.…”

“…The animal experiments were based on our previous reports. ,, Briefly, male C57BL mouse used for in vivo experiment was first anesthetized with chloral hydrate (25 mg/mL, initial dose of 500 mg/kg (i.p. ), additional doses of 100 mg/kg (i.p.)…”

Ratiometric Electrochemistry: Improving the Robustness, Reproducibility and Reliability of Biosensors

“…The electrodes afforded a good dynamic range between 1 and 100 µM and an LOD of 0.2 µM. The simplicity of fabrication was also paramount in work by Gu et al, who constructed a GO-GCE labelled electrostatically with MB [101]. The resultant electrode was utilised in the measurement of cerebral ascorbic acid in in brain microdialysate, displaying excellent selectivity compared to other electroactive chemicals present in cerebral fluid.…”