Smarter materials for hospital and the environment
Interdisciplinary work by microbiologist Professor Tom Smith and the University’s materials science department has led to novel environmentally friendly coatings for anti-corrosion applications that have attracted attention across diverse industries, including industrial paint manufacturing. In orthopaedics, it has lead to the development of antimicrobial coatings for surgery and better measurement of the release of antibiotics in orthopaedic cement. The research has led to journal publications and patents, commercial interest, and contract research and consultancy for industry and the NHS.
The research
In 2005, Professors Smith and Akid initiated a collaboration combining Smith’s expertise in microbiology with Akid’s expertise in materials science to develop functionalised coatings with wide-ranging potential applications. The original coating concept, supported by a grant from the Regional Development Agency, combined a robust sol-gel coating with immobilised bacterial endospores to produce a biological anti-corrosion coating, effective against corrosion of aluminium alloy in the laboratory and during a six-month field trial at the Thames Barrier, conducted in collaboration with the Environment Agency.
Use of immobilised bacteria is better than other functionalised coatings in that bacterial growth has the capacity to replenish the active agent, and the sol-gel coating offers a physically more robust matrix for long-term immobilisation than softer hydrogels. Smith’s insight as a microbiologist enabled a critical improvement, which involved immobilising the bacteria in the form of endospores, the most resistant life-form known, which can withstand the harsh conditions imposed during coating curing.
Smith and Akid also produced a derivative coating containing antibiotics, for use as controlled-release antimicrobial coatings in orthopaedic surgery. Results indicated that the coating would give protection during the critical perioperative period when pathogenic microorganisms can enter the surgical wound. These encouraging results led to a Medical Research Council (MRC) grant, with microbiology and coating development being conducted in the Biomedical Research Centre at the University under Smith’s supervision and in vivo trials on rats by collaborator Hatton at the University of Sheffield.
These technologies have been patented by the University and Smith’s lead position in the field has been further consolidated by a recent comprehensive review article. Our work toward antimicrobial coatings for orthopaedic surgery led local orthopaedic surgeons and consultant microbiologists to become aware of Smith’s group's expertise and led to a study characterising elution kinetics of antibiotics from orthopaedic cement that was required in order to inform clinical practice in orthopaedic surgery.
Collaborative research with the BMRC at Sheffield Hallam University evaluating the elution properties of different antibiotics from acrylic bone cements has made a significant impact in the management of difficult periprosthetic joint infections.
Nationally recognised senior consultant orthopaedic surgeon
The impact
The impact of these findings has been felt both in areas requiring anti-corrosive coatings and in the area of orthopaedic surgery.
Presentations on the anti-corrosion and anti-fouling technology delivered to audiences with substantial commercial representation have included an oral presentation at “Advances in Corrosion Protection by Organic Coatings” (Cambridge, 2009) and invitations to present at The Institute of Materials, Minerals and Mining (London, 2010). Interested companies included International Paint, a subsidiary of AkzoNobel N.V., the world's largest coatings manufacturer. This reflects an acute need for non-polluting new coating technology to be developed further in the marine engineering sector as well as other industries. Increasingly stringent environmental legislation has focused commercial interest in the coating. Identified beneficiaries include the shipping industry, off-shore power generation companies.
Collaboration with NHS consultant orthopaedic surgeons at the Sheffield Teaching Hospitals NHS Foundation Trust (STH NHS FT) on the use of the antimicrobial coatings resulted in further applications of the coating technology in relation to infection control following joint replacement operations. In addition, our discussions with orthopaedic consultants have led to contract research on the suitability of new antibiotics in orthopaedic cement to inform clinical practice and to help combat increasing antibiotic resistance in the clinical arena.
The Sheffield Teaching Hospital Research and Development Fund supported Smith in delivering two projects in 2012, to address specific needs to determine which antibiotics could be used in orthopaedic cement in difficult-to-treat cases of revision surgery. Results have been communicated to clinicians in the STH NHS FT and will be submitted to peer-reviewed journals shortly.
Collaboration with clinicians led to Smith advising Heraeus, a manufacturer of orthopaedic bone cement, on measurement of elution rates of antibiotics from their bone cement products. Our work with pharmaceutical manufacturer Eumedica allowed us to establish that the antibiotic temocillin that they supplied remained active after curing of bone cement and eluted on a timescale that suggests it would be appropriate for use in surgery. Funding for a larger project was provided by Pfizer PLC via an Anti-Infectives Research Foundation grant to Smith and Akid in MERI at SHU. This project investigated the elution of antibiotics linezolid and tigecycline to assess their suitability for use in orthopaedic cement.
As an extension of this work, we have trained three orthopaedic practitioners in the orthopaedic department of STH NHS FT in methodology and theory relating to measurement of antibiotic elution from orthopaedic cement.