Abstract
Purpose: :
This presentation discloses new ideas and preliminary results on the development of a "metabolic prosthesis" for local oxygenation of ischemic tissue under physiologically neutral conditions. The work was motivated by the potential clinical benefits of direct application of molecular oxygen for the treatment ischemic disease such as diabetic retinopathy.
Methods: :
The method of oxygen delivery is based on a new discovery in electrode-electrolyte interface science. Selective electrolysis of physiological saline and chemical formulations of vitreous humor has been performed with charge-limited pulsed electrolysis. In addition, we introduce the pH clamp, a three-electrode electrolysis technique that allows the pH-neutral electrolytic production of oxygen during the electrolysis of physiological fluids.
Results: :
We report repetitively-pulsed charge-limited electrolysis of physiological saline for the production of metabolic oxygen and suppression of free chlorine. Using 800 µA amplitude current pulses and <200 µsec pulse durations, we demonstrate prompt oxygen production and delayed chlorine production at the surface of a fused 0.85 mm diameter spherical platinum electrode. The data, interpreted in terms of the ionic structure of the electric double layer, suggest a strategy for in situ production of oxygen via a new class of "smart" prosthetic implants for dealing with ischemic disease such as diabetic retinopathy. We also present data indicating that drift of the local pH of the oxygenated environment can be eliminated using a feedback-controlled three electrode electrolysis system that chooses anode and cathode pair based on pH data provided by local microsensors.
Conclusions: :
A new method for treating ischemic disease, such as diabetic retinopathy, is described. Based on recent advances in retinal prosthetic implant devices [Artificial Sight, Humayun et al. (Eds.), Springer, New York (2007)], key surgical techniques required to implement the method of selective electrochemical oxygen production have been developed.
Keywords: diabetic retinopathy • neovascularization • oxygen