Leading scientists at the University of Sheffield have discovered nanotechnology could hold the key to preventing deep bone infections, after developing a treatment which prevents bacteria and other harmful microorganisms growing.
The pioneering research, led by the University of Sheffield's School of Clinical Dentistry, showed applying small quantities of antibiotic to the surface of medical devices, from small dental implants to hip replacements, could protect patients from serious infection.
Scientists used revolutionary nanotechnology to work on small polymer layers inside implants which measure between 1 and 100 nanometers (nm) – a human hair is approximately 100,000 nm wide.
Lead researcher Paul Hatton, Professor of Biomaterials Sciences at the University of Sheffield, said: "Microorganisms can attach themselves to implants or replacements during surgery and once they grab onto a non-living surface they are notoriously difficult to treat which causes a lot of problems and discomfort for the patient.
"By making the actual surface of the hip replacement or dental implant inhospitable to these harmful microorganisms, the risk of deep bone infection is substantially reduced.
"Our research shows that applying small quantities of antibiotic to a surface between the polymer layers which make up each device could prevent not only the initial infection but secondary infection – it is like getting between the layers of an onion skin."
Bone infection affects thousands of patients every year and results in a substantial cost to the NHS.
Treating the surface of medical devices would have a greater impact on patients considered at high risk of infection such as trauma victims from road traffic collisions or combat operations, and those who have had previous bone infections.
Professor Hatton added: "Deep bone infections associated with medical devices are increasing in number, especially among the elderly.
"As well as improving the quality of life, this new application for nanotechnology could save health providers such as the NHS millions of pounds every year."
The study, funded by the European Commission and the UK Engineering and Physical Sciences Research Council, is published in Acta Biomaterialia.
Research aims to improve hip and knee replacement success
Washington State University researchers are working to improve materials used in hip and knee replacements so that they last longer and allow patients to quickly get back on their feet after surgery.
Led by Susmita Bose, professor in the School of Mechanical and Materials Engineering, the researchers have received a five-year, $1.8 million National Institutes of Health grant to improve the way bone implants integrate into the body.
Better bone-like material the goal
Every year, approximately 1 million hip and knee replacement procedures are done in the U.S. State-of-the-art titanium replacements are generally affixed using acrylic bone cement. Patients are often out of bed and walking within a day or two of surgery.
But the materials used are foreign to the human body and don't bond strongly to surrounding tissues, resulting in typical implant failure within 10-15 years. This becomes problematic for younger patients or those who need revision surgeries.
Coatings for titanium implants create a natural-feeling surface so surrounding tissue can better bond to it. But the bone-like materials used for coatings are weaker than natural bone, so recovery from surgery takes a long time. Patients wait weeks to walk, rather than days.
With the new grant, researchers aim to improve the bone-like material that is used as a coating, so the titanium-based implants will attach better to surrounding tissue, act more naturally within the body and last longer.
Minerals, medications added to coatings
The researchers will mix ions commonly found in the body - such as magnesium, zinc and calcium - into their coatings. They also will add tiny amounts of medicine, such as antibiotics or osteoporosis medications, to the coatings.
They already have received patents on their innovative method of delivering medicine to a patient, which could be used like a time-release drug to fight infection or to build bone strength.
"This work could have a profound effect for younger patients and for those who undergo revision surgeries where bone volume is compromised,'' said Bose.
"A few extra years for these hip or knee replacements can make a tremendous difference,'' said research team member Amit Bandyopadhyay, also of WSU's School of Mechanical and Materials Engineering.
Expanding on nanomaterials research
Bandyopadhyay and Bose have been leaders for more than a decade in 3D printing of bone materials and improved materials for bone implants. In preliminary studies, they have used nanomaterials to make coatings that are stronger and more biocompatible than those currently available. The grant will allow them to further test the new coatings. Others on the team are William Dernell of the WSU College of Veterinary Medicine, physicians from Stanford University and the University of Washington medical schools, and graduate and undergraduate students from a variety of disciplines
Breakthrough could prevent hip implant replacement
Hip implants rely on the normal functioning of bone cells to achieve fixation of the implant with the bone. However, small metal particles released from hip implants, due to friction between the moving surfaces, have been shown to be toxic to the surrounding bone cells.
This causes the implant to loosen in the bone and often leads to patients requiring second surgery to replace the failed implant.
Using X-ray light from the Diamond Light Source, the UK's synchrotron science facility at Harwell Science and Innovation Campus in Oxfordshire, researchers were able to map the locations of metals inside bone cells.
The findings, published in the Journal of Orthopaedic Research, show that the location of the metals that are released from implants is different inside bone building and bone destroying cells.
Dr Alison Gartland, Senior Lecture from the University's Academic Unit of Bone Biology, said: "The fact that we found metal ions in different places within the two types of bone cells suggest that they get into the cells by separate ways.
"When investigating how the metals entered bone cells we found that when they blocked a molecule called the P2X7 receptor using a specific drug, the entry of metals into the bone cells was reduced.
"These results are really exciting because, if we can prevent the entry of the metal into these cells, we can hopefully prevent the metal joint from failing."
Over the last decade, it is estimated that nearly half a million hips have been replaced in England and Wales as a result of osteoarthritis.
Osteoarthritis is the most common joint disorder in adults, affecting nearly eight million people in the UK alone. Surgical replacement of the joint using artificial metal implants is the most effective way to restore activity and reduce pain and disability in osteoarthritis sufferers.