D-serine is the major D-amino acid in the mammalian central nervous system. As the dominant co-agonist of the endogenous synaptic NMDA receptor, D-serine plays a role in synaptic plasticity, learning, and memory. Alterations in D-serine are linked to neuropsychiatric disorders including schizophrenia. Thus, it is of increasing interest to monitor the concentration of D-serine in vivo as a relevant player in dynamic neuron-glia network activity. Here we present a procedure for amperometric detection of D-serine with self-referencing ceramic-based microelectrode arrays (MEAs) coated with D-amino acid oxidase from the yeast Rhodotorula gracilis (RgDAAO). We demonstrate in vitro D-serine recordings with a mean sensitivity of 8.61 ± 0.83 pA/µM to D-serine, a limit of detection (LOD) of 0.17 ± 0.01 µM, and a selectivity ratio of 80:1 or greater for D-serine over ascorbic acid (mean ± SEM; n = 12) that can be used for freely moving studies.
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This work was supported by Deutsche Forschungsgemeinschaft SFBTR654 Plasticity and Sleep (TPA06) and Deutsche Forschungsgemeinschaft SPP1665 (MA2053/4-2).
The following are available online at https://www.mdpi.com/2079-6374/8/1/20/s1, Figure S1: In vitro calibration of one D-serine detecting Microelectrode Array (MEA) using 1 mM D-serine challenges, Figure S2: Linearity (R2) curve obtained from the calibration of the RgDAAO coated D-serine detecting MEA depicted in Figure 2, Table S1: In vitro calibration measurements for the RgDAAO coated D-serine detecting MEAs using final concentrations of 1 µM D-serine in the solution media (n = 5; mean ± SEM), Table S2: In vitro calibration measurements obtained from the calibration of the RgDAAO coated D-serine detecting MEA depicted in Figure 2.
Campos-Beltrán, Diana; Konradsson-Geuken, Åsa; Quintero, Jorge E.; and Marshall, Lisa, "Amperometric Self-Referencing Ceramic Based Microelectrode Arrays for D-Serine Detection" (2018). Neuroscience Faculty Publications. 48.