The Hohenstein Institute was founded by Prof. Dr.-Ing. Otto Mecheels in Bönnigheim in 1946. It is an internationally recognized research and service centre and is also home to the Institute for Hygiene and Biotechnology (IHB) which concentrates on life sciences research. Since 2001, the IHB has been under the leadership of Prof. Dr. Dirk Höfer, a human biologist who has focused on making medicine the focal point of the institute. Since then, many publicly funded research projects have been carried out, products have been brought to market on behalf of customers, and numerous scientifically recognized test methods have been established and adapted to the specific requirements of textile materials used in medical applications. With a laboratory space of 250 m², including microbiotechnological and biotechnological laboratories, the IHB's application-oriented scientists are working on topics such as innovative materials, regenerative medicine, medical microbiology as well as occupational and environmental medicine. The IHB is particularly interested in developing products and providing services that are geared towards economic applications.

In the field of applied hygiene, the IHB has been carrying out hygiene controls on behalf of “Gütegemeinschaft Sachgemäße Wäschepflege e.V.” (German Certification Association for Professional Textile Services) since 1996. “We are inspecting the reprocessing procedures of clinical laundry of around 350 commercial laundries in Germany,” Prof. Höfer explains, highlighting the fact that such inspections take into account a broad range of different criteria, including the personal hygiene of laundry staff, the disinfecting washing process as well as the laundry items themselves. In addition, the IHB inspects the general conditions of hygiene of health care institutions, catering businesses as well as the hygiene of textiles used in hospitals and care homes.

IHB research involves the investigation of the role of textiles in chains of infection as well as the effect of operating theatre clothing in protecting against the transfer of germs from the operating surgeons into patients' wounds. The IHB researchers also investigate and evaluate antimicrobial products. “We are developing efficacy-time profiles in order to determine the efficacy of such products under practical conditions,” said Höfer. 

The IHB is focused on developing innovative textile systems for medical applications and is funded by the EU and the German and state governments. The institute also carries out research on behalf of industrial companies. Although research is specifically focused on fibres and textiles, the IHB’s products and services have, at first sight, little to do with “classical” textile research. In addition, the beneficiaries of the IHB’s research projects no longer include just textile manufacturers. For example, the IHB is working on the development of materials for use as innovative wound dressings. “Which new fibres can be used for the targeted therapy of wounds?” is one of the questions Dirk Höfer and his team are investigating. In their effort to find an answer to this question, the researchers use tubular, cellulose-containing fibres that are coated with antibiotics or cell-enhancing and cell-renewing substances. The combination of these fibres with cellulase-coated fibres enables the targeted and delayed release of the drugs contained in the wound dressing.

The active substances are incorporated into wound dressings that are made of a dry needled fleece. “This has the advantage that the drugs are dispensed over a period of several hours and over a relatively constant effective range, rather than at high concentrations right at the time when they are applied,” Höfer explains. The scientists have been able to show with model substances applied to a small group of patients that the substances can be effectively released using this innovative treatment concept. The innovative wound dressings have already been tested in initial clinical studies in cooperation with pharmaceutical companies and other partners. The treatment concept with drug delivery function might be of great interest to producers of active substances, pharmaceutical companies, hospitals and care institutions. It is of no surprise that the treatment concept has received great interest from the health care sector as the results of the research project suggest that health care costs, as well as the treatment times for patients, can be reduced.

Natural biopolymers such as chitosan have been shown to have great potential in medical applications. Basic research focuses on the use of chitosan scaffolds for applying stem cells into the human body and the IHB’s researchers have already investigated the interaction of stem cells and chitosan. The researchers are still trying to find out the effect of chitosan on the proliferation and differentiation of stem cells. Höfer also pointed out that his team is focusing on an effect of stem cells that has for a long time been neglected: the effect of stem cells on angiogenesis, i.e. the growth of new blood vessels. In order to exploit this effect, the stem cells are applied to the surface of tubular fibres and the necessary growth-promoting factors to the inside of the fibres. “We are mimicking the natural environment of the human body, in which the basal lamina, a layer of extracellular matrix secreted by the epithelial cells, provides the stem cells with growth-promoting factors that promote the formation of new blood vessels,” said Höfer, highlighting the researchers’ goal of developing three-dimensional scaffolds that can be effectively integrated into the tissue as a result of the stem cells’ angiogenic properties.

The IHB’s alginate research also focuses on blood vessels. It is the objective of IHB researchers to produce hollow fibres from the salts of alginic acid and then cover them with endothelial cells. This procedure might enable the scientists to generate artificial blood vessels. The researchers are also developing a biopolymer fibre-based fatty tissue substitute with enhanced biocompatibility that is suitable for the treatment of extensive tissue defects.

The IHB is mainly focused on turning research results into marketable commodities. For example, the institute has developed textile heating elements that prevent loss of body heat in patients in the operating theatre. The heating elements consist of a conductive yarn that is knitted into a polyester fabric. The thin textile heating system, which consists of modules for arms, legs, chest and stomach, can be rapidly heated to 36°C. Its modular structure means that the operated area remains uncovered. The hypothermia prevention system is currently in the last phase of clinical testing and is estimated to be on the market in 2012.

In an area accredited by the ZLG - Zentralstelle der Länder für Gesundheitsschutz, IHB is investigating the effects of interaction of textiles and utensils with people and the environment. The question as to whether products have negative (toxicological) effects on human health is not only of importance for products used for medical application, although it is one of the most important areas. In the field of environmental toxicity testing, which relates to testing the effect of products or specific (surface) coatings on the environment, IHB completely avoids the use of experimental animals. Instead, the researchers use chicken and fish eggs as well as skin models to assess aspects such as the irritating, cell-damaging or even genome-altering effects of potentially harmful substances.

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