When germs become expensive – and how antimicrobial coatings can reduce the burden on hospitals

Traditional disinfection measures are costly and have only limited effectiveness. Shortly after cleaning, germs can be detected on surfaces again, especially in heavily frequented areas. Many institutions have long been aware of the high personnel and material costs involved.

To break this cycle, research and industry are focusing on new materials: antimicrobial surfaces and coatings that are designed to permanently inhibit the growth of microorganisms. These ensure that surfaces remain hygienically stable between cleaning cycles. The aim is to reduce the germ load where many hands are involved: on bed frames, door handles, work surfaces, or medical devices. Hygiene thus becomes a property of the surface itself.

There are many different approaches to making surfaces active against microorganisms. Some methods are already in use, while others are still being tested.

Silver and copper ions are among the oldest antimicrobial agents. Both attack the cell structure of bacteria and disrupt their metabolism. Manufacturers such as the Wieland Group have used them to develop alloys such as CopperLine, which are used, for example, in door handles, grab rails, and handrails. Nanoscale silver coatings such as Agpure® from Ras AG are also used to give plastics an antimicrobial function.

These technologies have been well researched scientifically and are established in practice. Open questions mainly concern long-term stability and the handling of released metal ions in sensitive areas.

A more recent approach is based on titanium oxide (TiO₂), a light-active semiconductor material. Under UV or visible light, reactive oxygen species are formed on the surface, which decompose organic substances and microorganisms. Coatings of this type are already being used in architecture, for example by Sto SE or in collaborations such as Pureti / CristalACTiV (BASF).

This technology is particularly interesting for hospitals because it does not require chemical additives and remains effective as long as there is sufficient light. This makes it a potentially sustainable solution for hygienically sensitive rooms.

Another variant is antimicrobial additives in polymers. Here, active ingredients are incorporated directly into coatings or plastics so that the surface has a permanent biocidal effect. Systems such as BioCote® or Microban® are already in use in medical devices, handles, and furniture. They provide a stable, mechanically resilient protective film, especially for applications outside the direct patient environment.

While established technologies are already helping to raise hygiene standards, research is working on a new generation of intelligent coatings.

In the EU-funded project NOVA – Next Generation BiOactiVe NAnocoatings, 14 partners from nine countries – including Fraunhofer IFAM and Evonik – are developing materials that not only kill germs but also prevent them from adhering in the first place. The surfaces are nanostructured; their fine topography makes it difficult for microorganisms to attach themselves.

In addition, photodynamic systems are also being researched. In contrast to classic photocatalysis, in which titanium oxide usually forms reactive oxygen species under UV or visible light, these are based on special dyes that are activated even under normal room lighting. They also produce oxygen compounds that act against bacteria and viruses without promoting the development of resistance.

Companies such as Polaroid Therapeutics are also pursuing this approach. Their light-activated polymers could be used in the future on catheters, implants, or hospital furniture – in other words, materials that come into constant contact with germs.

The economic dimension is playing an increasingly important role in hygiene. A single hospital infection is estimated to cause between €5,000 and €20,000 in additional costs – for medication, isolation, follow-up treatment, and extended stays. Antimicrobial surfaces are an investment in long-term prevention. This approach could be particularly worthwhile in areas with large surface areas, such as intensive care units or operating room preparation rooms.

Further development work is needed before coatings such as those from the NOVA project can be used in clinics. Test procedures, standards, and long-term tests under real conditions must show how durable and effective the materials remain over many years.

But the trend is clear: in the future, cleaning will no longer be the only means of ensuring hygiene – the surfaces themselves will also make an active contribution to infection prevention. This will reduce the workload on staff, cut costs, and open up new avenues for greater safety in everyday hospital life.

Antimicrobial coatings are an example of how technological innovation and cost-effectiveness can go hand in hand.