A Portable Oxygen Concentrator for Wound Healing Applications
EPIFLO® (Ogenix, Beachwood, OH). (Figure 1) is a commercially available device that can deliver Transdermal Continuous Oxygen therapy and represents an inexpensive alternative to systemic hyperbaric oxygen therapy without the side effects of vasoconstriction, toxicity, and tissue destruction associated with the latter. EPIFLO is a light-weight (~100 g) electrochemical oxygen concentrator with no moving parts and silent operation. It generates continuously 3 mL/hour oxygen (98+% purity) and delivers to the wound site through a cannula tubing. It employs leading-edge oxygen ‘fuel cell’ concentration technology to stimulate tissue regenerative processes driving closure of delayed-healing acute or chronic wounds. This product is US FDA approved for a broad range of indications as a Class II Medical Device; prescribed on order of a physician. It is also CE, ISO 13485:2003 and CMDCAS (Canadian Medical Devices Conformity Assessment Scheme) Health Canada Certified
The heart of the device is a Membrane Electrode Assembly (MEA) consisting of a perfluorosulfonic acid cation exchange membrane, such as NafionR, interposed between two high area electrodes made of finely divided Pt based metal catalysts (Figure 2). Atmospheric air composed mostly of ~ 21 % oxygen, 78 % nitrogen is exposed to the device through the slots in the seam formed between the lid and the bottom part of the enclosure, where when activated using a small battery, it promotes the reduction of dioxygen at the cathode and the oxidation of water at the anode to produce oxygen delivered through a suitable tubing to the wound. Since the cation exchange membrane has overall very low gas permeability, gases cannot permeate through the membrane, thus ensuring a higher than 98% purity of the product oxygen.