Enzyme-based choline and L-glutamate biosensor electrodes on silicon microprobe arrays.

Area of Science:

• Neuroscience
• Biomedical Engineering
• Electrochemistry

Background:

• Accurate measurement of neurotransmitters like choline and L-glutamate is crucial for understanding brain function.
• Existing methods for in vivo neurotransmitter detection face challenges in selectivity, sensitivity, and long-term stability.

Purpose of the Study:

• To develop and characterize novel brain-implantable microprobe arrays for the simultaneous detection of choline and L-glutamate.
• To evaluate the performance of these biosensors in vitro and in vivo.

Main Methods:

• Fabrication of microprobe arrays using silicon micromachining (DRIE) with recessed platinum microelectrodes and an Ag/AgCl reference electrode.
• Coating microelectrodes with enzyme membranes and m-phenylenediamine layers using electrochemically aided adsorption (EAA) and electrochemical polymerization.
• Functionalization for selective detection of choline and L-glutamate at physiological concentrations.

Main Results:

• Achieved high sensitivity for choline (132±20 µA mM⁻¹ cm⁻²) and L-glutamate (95±20 µA mM⁻¹ cm⁻²).
• Demonstrated limits of detection below 0.5 µM for both analytes.
• Confirmed functional viability of the biosensors through in vitro and in vivo experiments.

Conclusions:

• The developed microprobe arrays offer a promising platform for simultaneous, selective, and sensitive in vivo monitoring of choline and L-glutamate.
• The fabrication and functionalization techniques are compatible with parallel processing and precise spatial control for multi-analyte detection.
• These biosensors have significant potential for advancing neuroscience research and clinical applications.