Optimization of amperometric microsensors for monitoring choline in the extracellular fluid of brain tissue
1995; Elsevier BV; Volume: 307; Issue: 2-3 Linguagem: Inglês
10.1016/0003-2670(94)00558-4
ISSN1873-4324
AutoresMichael G. Garguilo, Adrian C. Michael,
Tópico(s)Medicinal Plants and Neuroprotection
ResumoMicrosensors for choline with selectivity over ascorbate have been prepared by immobilizing horseradish peroxidase and choline oxidase within a cross-linkable redox polymer deposited onto 10-μm diameter carbon fiber microcylinder electrodes, ca. 300–400 μm in length. To eliminate ascorbate interference, microsensors are modified by incorporating ascorbate oxidase into the sensing membrane and by applying a Nafion overlayer. When operated at 37 ° C at an applied potential of −0.1 V vs. Ag/AgCl, the microsensors detect 10 μm to 1 mM choline with no interference from 0–400 μM ascorbate. The modified choline microsensors detect 0–100 μM choline in a linear fashion (r = 0.99), again with no ascorbate interference. At 37 ° C the microsensors detect 10 μM Ch with a signal-to-noise ratio of 12 and a response time of ca. 15 s (10–90% of the change in signal). In order to evaluate their performance in vivo, the microsensors were implanted into the brain of a rat alongside a micropipet from which small volumes (75–250 nl) of a choline solution were injected into the tissue.
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