Fig. 1.

Microelectrode array coating scheme for adenosine measures. Diagram depicts chemical reactions and enzymatic coating scheme applied to the platinum (Pt) recording sites of each microelectrode array (MEA). Generation of the reporter molecule, H₂O₂, from extracellular adenosine required three enzymes (ADA, NP, XO). The distal recording sites were coated with ADA, XO, and NP, while the proximal sites were coated with only XO and NP. An exclusion layer (mPD) prevented large-molecule interferents (ascorbic acid) from reaching the Pt surface, while still allowing passage of H₂O₂ for oxidation. Pt recording sites 50 × 150 μm².