Continuous and Simultaneous Electrochemical Measurements of Glucose, Lactate, and Ascorbate in Rat Brain Following Brain Ischemia

Abstract

Developing new tools and technologies to enable recording the dynamic changes of multiple neurochemicals is the essence of better understanding of the molecular basis of brain functions. This study demonstrates a microfluidic chip-based online electrochemical system (OECS) for in vivo continuous and simultaneous monitoring of glucose, lactate, and ascorbate in rat brain. To fabricate the microfluidic chip-based detecting system, a microfluidic chip with patterned channel is developed into an electrochemical flow cell by incorporating the chip with three surface-modified indium-tin oxide (ITO) electrodes as working electrodes, a Ag/AgCl wire as reference electrode, and a stainless steel tube as counter electrode. Selective detection of ascorbate is achieved by the use of single-walled carbon nanotubes (SWNTs) to largely facilitate the electrochemical oxidation of ascorbate, while a dehydrogenase-based biosensing mechanism with methylene green (MG) adsorbed onto SWNTs as an electrocatalyst for the oxidation of dihydronicotiamide adenine dinucleotide (NADH) is employed for biosensing of glucose and lactate. To avoid the crosstalk among three sensors, the sensor alignment is carefully designed with the SWNT-modified electrode in the upstream channel and paralleled glucose and lactate biosensors in the downstream channels. With the microfluidic chip-based electrochemical flow cell as the detector, an OECS is successfully established by directly integrating the microfluidic chip-based electrochemical flow cell with in vivo microdialysis. The OECS exhibits a good linear response toward glucose, lactate, and ascorbate with less crosstalk. This property, along with the high stability and selectivity, enables the OECS for continuously monitoring three species in rat brain following brain ischemia.

Smart Nanocomposites of Cu-Hemin Metal-Organic Frameworks for Electrochemical Glucose Biosensing

“…As an important research area of analytical chemistry12345, electrochemical glucose biosensors have received significant attention over past few years because of their low cost, quick response, simple preparation and wide applications in biomedical, clinical research, food production, ecology and even textile industry6789. Particularly, glucose oxidase (GOD)-based glucose biosensors have been one of the hot spots in analytical chemistry as the introduction of nanomaterials1011.…”

Fe3+-functionalized carbon quantum dots: A facile preparation strategy and detection for ascorbic acid in rat brain microdialysates

“…Detecting the level of substances in brain microdialysates is important for physiology, pathology and clinics, and many reports use detection assays for neuromolecules such as ascorbate, glucose, lactate and dopamine in rat brain microdialysates [40][41][42]. In our experiment, an unknown amount of AA in a rat brain microdialysis sample was estimated by using the standard addition method with 5 µM AA solution.…”

“…Although many approaches were well-established, sophisticated instrumentation, tedious sample preparation and separation procedures involved limit their practical applications. To resolve these problems, Mao group successfully developed electrochemical methods with high selectivity and reproducibility for in vivo/online measurement of AA [9]. Nevertheless, more simple but effective measurement methods for AA in the cerebral systems are still urgently desired.…”

Covalent functionalization and electrochemical tuning of reduced graphene oxide for the bioelectrocatalytic sensing of serum lactate

“…The amperometric biosensing of lactate requires either the enzyme lactate oxidase (LOx) [13][14][15] or lactate dehydrogenase (LDH). 16 The biosensing of lactate with LOx involves the quantification of enzymatically generated H 2 O 2 . The amount of H 2 O 2 generated during the enzymatic reaction is proportional to the concentration of lactate present in the sample.…”