Figure 4.

(A) Procedure for hydrogel coating the neural electrodes. Optical images of reswelling of the hydrogel-coated electrodes in an agar (1%)-phantom matrix as a function of time. HG coatings in the agar matrix made of (B) PBS and (C). deionized water. (C) Plot of reswelling of hydrogel coatings in the PBS agar. The initial thickness of hydrogel coatings was 50 lm as determined by optical microscopy during the dipcoating process. (E) The average percentages of clearly detectable units as a function of the thickness of hydrogel-coated electrodes in the auditory cortex with a 200 ms noise burst. The HG thickness indicates the initial thickness of hydrogel coatings before drying. The inset shows a representative recorded signal with a SNR of 5.0. (*) Significance between control (bare electrode) and hydrogel-coated electrodes. Reproduced with permission.[5] Copyright 2010