Mammalian cochlea perilymph contains amino acids and protein which have a m
ajor effect on the electrochemistry of an implanted auditory prosthesis. Cy
clic voltammetry in an artificial perilymph solution shows that many amino
acids adsorb at the platinum electrode diminishing oxidation of the metal,
and also blocking hydrogen evolution. At anodic potentials > 900 mV vs. sil
ver/silver chloride they are oxidized leaving adsorbed oxidation products.
The sulfur-containing amino acids cysteine and methionine have the greatest
effects. Protein (human serum albumen, HSA) has a similar hat smaller effe
ct. A solution containing HSA (2 mg mL(-1)), phenylalanine (175 muM), glyci
ne (396 muM), and proline (40 muM) in phosphate buffered saline is proposed
as a suitable artificial perilymph solution having similar electrochemical
and adsorption properties to perilymph. (C) 2000 The Electrochemical Socie
ty. S0013-4651(99)12-019-4. All rights reserved.