Printed electronics make the wound dressing flat and flexible

In the case of minor injuries such as cuts, lacerations or lacerations, the skin regenerates quickly on its own. However, this is not the case with chronic and large wounds. Instead, they are often associated with a protracted and painful healing process and the lengthy therapies required as a result. Bedsores, pressure ulcers or diabetic foot ulcers are a good example of this. Every routine change of wound dressing is necessary on the one hand, but also means an ordeal for the patient - and thus a new injury that can delay the entire healing process. „Patients suffer a lot“, says Dr Carsten Mahrenholz, chemist, biologist and economist and one of the founders of Coldplasmatech GmbH from Greifswald. The company specialises in the treatment of slow-healing wounds using cold plasma technology.

Dr Mahrenholz and his team began their work by gathering information on the topic of wound healing. The team quickly realised that wound dressings were the method of choice. This is because, in addition to other advantages, they optimally complement existing treatment regimes and products. The interdisciplinary team, then still affiliated with the Leibniz Institute for Plasma Research (INP), then set itself a new challenge: to design a wound dressing that would enable healing plasma to be generated directly on the surface of the wound.

Violet-glowing cold plasma destroys bacteria
The INP scientists' research showed that cold plasma can efficiently kill bacteria and even the dreaded antibiotic-resistant pathogens commonly found in hospital and hospice environments. Cold plasma works exclusively through physical processes by attacking the cell membranes of the microbes, among other things.

Cold plasma, which can be recognised by its distinctive glow, is a natural phenomenon. Plasma forms, for example, when a gas flows through strong electric fields that separate its electrons from their molecules. This makes the gas electrically conductive and gives it a light violet colour. Dr Mahrenholz and his team were convinced that plasma can heal. Using silicone technology, the scientists worked on a solution for a wound dressing that generates a high-energy gas and applies it directly to damaged areas of skin, destroying bacteria and at the same time stimulating the body's self-healing powers.

Printed electronics: conductor track structure with multiple functional layers

The result was the CPTpatch, a flexible system in a range of wound dressings that utilises a plasma energy source, the CPTcube. „We needed something lighter, more reproducible and more user-friendly“, says Dr Mahrenholz. Coldplasmatech turned to film specialist Schreiner Protech from Oberleissheim, whose engineering team developed a customised EIF (Electronics-in-Film) solution for the next generation of CPTpatch. The inclusion of special printed electronics played a key role in this.

The requirements were manifold: on the one hand, a flexible conductor track structure was required for the wound dressing. The application had to withstand several thousand volts from the CPTcube energy source without causing an electric shock. High-precision printing and punching were other important criteria - a requirement that can sometimes clash with the need for ease of manufacture. This is where Schreiner Protech has identified the ideal materials for both medical applications and production efficiency.

The second iteration of CPTpatch integrates a conductor track structure made of a film composite with the ability to generate cold plasma. To ensure optimal adaptability to the parameters of different wound dressings, it comprises several functional layers including films, fully printed electrodes, an insulation layer and adhesives. The result is a solution that realises the wound healing capabilities of the original CPTpatch with a smaller footprint, lower electrical voltage and lower manufacturing complexity. (su)

Article from "medizin & technik" from 28/02/2023