Patent of the month: Harnessing the healing power of oxygen

Materials World magazine
1 Aug 2018

Dr Jennifer Unsworth, Patent Attorney at intellectual property law firm Withers and Rogers, reports on a newly patented way to aid wound healing.

The presence of oxygen at the siteof a wound can dramatically improve its chances of healing. With this in mind, Inotec AMD has developed an oxygen wound therapy system called Natrox, which is designed to promote healing. Described in recently granted UK patent, GB 2483520, the system is a safe and convenient way to treat a wound topically.

The use of oxygen therapy to treat wounds is well known. However, existing techniques have some drawbacks. In many instances, oxygen is applied to the wound from a gas cylinder, which can be inconvenient and restrictive for the patient. 

Methods also exist that do away with the need for oxygen cylinders, however these also have limitations. In some systems, a process of hydrolysis can generate oxygen. While this does not require an oxygen cylinder, a water reservoir is required, which can be bulky. This technique also produces hydrogen peroxide as a by-product, which is harmful to healthy cells and so can negatively affect the healing process.

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The Natrox device is a portable oxygen concentrator and delivery system, which generates oxygen without the need for an oxygen cylinder or water reservoir and avoids the production of hydrogen peroxide. The electrochemical process shown in the diagram above achieves this. 

The cell of the Natrox oxygen concentrator has a proton-conducting membrane, known as the Nafion membrane, which has an anode and cathode positioned on opposite sides. Water in the Nafion membrane, which is initially from the atmosphere, reacts at the anode to produce oxygen and at the cathode to produce hydrogen. Oxygen is continuously generated at the anode and is directed to the wound.

The hydrogen produced at the cathode passes through a diffusion layer to a catalyst layer, which is a sputtered layer of platinum at a density of 2mg/cm2. Here, the hydrogen reacts with oxygen from the atmosphere to produce water, which travels back to the Nafion membrane for further electrolysis.

In this way, water is taken from the atmosphere and recycled to produce oxygen. This removes the need for a separate water reservoir, since continuous oxygen production is achieved simply by recycling water via the catalyst layer. This makes the system more simple and portable for patients to use.

In the Natrox system, the oxygen concentrator is used together with a distributor, which takes the oxygen to the wound. Inotec AMD has also applied for patents to cover the oxygen distributor itself. If these are successfully granted, this will provide patent protection for each of the key components making up the Natrox system, resulting in more flexible and robust IP protection.

The need for topical oxygen therapy systems is becoming increasingly prominent and this patented technology shows how it is possible to overcome a number of problems associated with previous methods of oxygen therapy within the chronic wound care market.

Read the full patent here: