Fabrication and ex vivo evaluation of activated carbon–Pt microparticle based glutamate biosensor

Abstract

As one of the most abundant neurotransmitters in the brain and the spinal cord, glutamate plays many important roles in the nervous system. Precise information about the level of glutamate in the extracellular space of living brain tissue may provide new insights on fundamental understanding of the role of glutamate in neurological disorders as well as neurophysiological phenomena. Electrochemical sensor has emerged as a promising solution that can satisfy the requirement for highly reliable and continuous monitoring method with good spatiotemporal resolution for characterization of extracellular glutamate concentration. Recently, we published a method to create a simple printable glutamate biosensor using platinum nanoparticles. In this work, we introduce an even simpler and lower cost conductive polymer composite using commercially available activated carbon with platinum microparticles to easily fabricate highly sensitive glutamate biosensor using direct ink writing method. The fabricated biosensors are functionality superior than previously reported with the sensitivity of 5.73 ± 0.078 nA μM −1 mm −2 , detection limit of 0.03 μM, response time less than or equal to 1 s, and a linear range from 1 μM up to 925 μM. In this study, we utilize astrocyte cell culture to demonstrate our biosensor's ability to monitor glutamate uptake process. We also demonstrate direct measurement of glutamate release from optogenetic stimulation in mouse primary visual cortex (V1) brain slices.

Advances in Bioelectrode Design for Developing Electrochemical Biosensors

“…For example, electrodes as small as 35 μm resolution could be printed for glutamate biosensing using the DIW method. 236 The resolution of the printed pattern is dependent on the printing speed and dispensing pressure. Besides, the DIW method was found more advantageous in terms of sensitivity, specificity, and reduction in material consumption compared to the screen printing method.…”

Biopolymer Composites Material Extrusion and their Applications: A Review

“…Nguyen et al introduced a simple and inexpensive conductive polymer composite using activated carbon and platinum microparticles to fabricate highly sensitive glutamate biosensors using DIW. [ 190 ] With a linear range from 1 μM up to 925 μM, the manufactured biosensors had good sensitivity (5.73 ± 0.078 nA μ m −1 mm −2 ), a low detection limit (0.03 μ m ), and a quick response time (less than or equal to 1 s), showing direct detection of glutamate release after optogenetic activation.…”

Recent Progress of the Practical Applications of the Platinum Nanoparticle-Based Electrochemistry Biosensors

“…The sensor has a sensitivity of 973 ± 4 µA/mMcm 2 , a linear range of 0.004-0.9 mM, a detection limit of 0.1 µm, and showed excellent specificity and selectivity. Nguyen et al (2020) generated current on the surface of an electrode by converting glutamic acid into H 2 O 2 using commercial activated carbon and platinum particles and catalyzed by glutamate oxidase (Figure 2). This resulted in glutamate with a short response time, high sensitivity, and low detection limit.…”

“… Glutamate biosensors: A cross-sectional view of C-PT-PEDOT [poly (3,4 ethylenedioxythiophene)] (Nguyen et al, 2020 ). Reproduced with the permission from 2020 Elsevier B.V. …”