Co-Detection of Dopamine and Glucose with High Temporal Resolution

Abstract

Neuronal activity and brain glucose metabolism are tightly coupled, where triggered neurotransmission leads to a higher demand for glucose. To better understand the regulation of neuronal activity and its relation to high-speed metabolism, development of analytical tools that can temporally resolve the transients of vesicular neurotransmitter release and fluctuations of metabolites such as glucose in the local vicinity of the activated neurons is needed. Here we present an amperometric biosensor design for rapid co-detection of glucose and the neurotransmitter dopamine. The sensor is based on the immobilization of an ultra-thin layer of glucose oxidase on to a gold-nanoparticle-covered carbon fiber microelectrode. Our electrode, by altering the potential applied at the sensor surface, allows for the high-speed recording of both glucose and dopamine. We demonstrate that, even though glucose is electrochemically detected indirectly through the enzymatic product and the electroactive dopamine is sensed directly, when exposing the sensor surface to a mixture of the two analytes, fluctuations in glucose and dopamine concentrations can be visualized with similar speed and at a millisecond time scale. Hence, by minimizing the enzyme coating thickness at the sensor surface, dual detection of glucose and dopamine can be realized at the same sensor surface and at time scales necessary for monitoring fast metabolic alterations during neurotransmission.

Fibrotic Encapsulation Is the Dominant Source of Continuous Glucose Monitor Delays

“…Continuous glucose monitor (CGM) readings can lag behind blood glucose by as much as 20 min, and this delay limits their use as a stand-alone glucose-monitoring technology ( 1 ). In laboratory settings, glucose oxidase sensors can record fluctuations in glucose concentration with millisecond-scale time resolution ( 2 ), thus raising the question of why CGM readings are so delayed. Substantial efforts have been made to identify the sources of CGM latency using an indirect approach ( 3 ).…”

Metal-Oxide Based Nanomaterials: Synthesis, Characterization and Their Applications in Electrical and Electrochemical Sensors

“…As already outlined, the precise quantification of glucose and DA is crucial both for analytical applications and in diagnostic research, since they are key in physiology and above all are coupled with important diseases such as diabetes mellitus, Parkinson’s disease and schizophrenia [ 143 , 144 ]. It is well known that the amount of DA, being a fundamental catecholamine neurotransmitter in the mammalian central nervous system, affects the body physiological functions [ 145 ], and it is also correlated with brain glucose metabolism that, in neuronal activity, triggers the transients of vesicular neurotransmitter release and fluctuations of metabolites in the proximity of the activated neurons [ 146 ]. Recently, a simultaneous detection of glucose and DA was carried out using CuO and hybrid nanostructures composed by CuO and graphitic carbon nitrides (g-C 3 N 4 ) [ 147 , 148 , 149 , 150 ].…”

Frontiers in electrochemical sensors for neurotransmitter detection: towards measuring neurotransmitters as chemical diagnostics for brain disorders

“…The Cans group constructed an amperometric biosensor by immobilizing an ultra-thin layer of glucose oxidase onto a Au-nanoparticlecovered CFM that permitted the simultaneous monitoring of glucose and DA with millisecond temporal resolution for both analytes. 142 Other surface modications have enabled detection of other analytes with DA. Cincotto et al modied glassy carbon electrodes with a hybrid material consisting of mesoporous silica nanoparticles, graphene, and silver nanoparticles for simultaneous electrocatalytic reduction measurements of DA and epinephrine.…”