19th European Conference on Biomaterials

The European Society for Biomaterials (ESB) held its 19th European Conference on Biomaterials between the 11th and 15th September 2005, in Sorrento, Italy. These annual meetings of the ESB provide an opportunity for materials scientists, engineers, biologists, chemists and other scientists to convene and discuss the latest advances in the field of biomaterials. From the 900 abstracts submitted, there were 330 podium presentations scheduled, together with 520 poster presentations. Therefore, this was an important gathering and there were over 1000 attendees at the conference. In addition to the presentations, there were trade stands representing a number of bodies concerned with biomaterials, from organizations such as the University of Brighton to manufacturers such as MTS and Veeco. The podium presentations were divided among 54 separate sessions, usually with four sessions running in parallel. There were sessions on topics including scaffolds, surface modification, degradable polymers and composites, tissue engineering, nanostructures, hydrogels, biomimetic materials, material–cell interactions, protein adsorption, soft-tissue repair, ultra-high molecular weight polyethylene, dental materials and drug delivery. In addition, a number of sessions were held jointly with the European Society for Biomechanics and with the European Society for Tissue Engineering. There were dedicated poster sessions on the Monday, Tuesday and Wednesday of the conference, so that delegates had a good opportunity to view posters and meet with their authors.

Moreover, there were four ESB award lectures, each lasting 30 min and timetabled so as not to clash with any other session. These lectures were:

•	Surfaces to control implant tissue adhesion for osteosynthesis: in vitro and in vivo analysis by Geoff Richards of the AO Research Institute, Davos, Switzerland
•	Tissue engineering: a bridge between material science and life sciences by Charles Baquey of the University of Bordeaux, France
•	Biomolecular aggregation: a natural bottom-up approach towards biofunctionality by Matteo Santin of the University of Brighton, UK
•	Artificial biopolymers: successful present and promising future by Michael Vert of Montpellier University, France

Prior to the meeting, a workshop was held entitled ‘scanning electron microscopy of biomaterials and biological interfaces’. During the meeting the ‘4th Young Scientists Forum’ was held which included sessions on a European PhD in biomaterials and tissue engineering, as well as a session on networking and funding for young scientists. Immediately after the ESB meeting, a consensus satellite meeting was held to discuss updating definitions in biomaterials. This was under the chairmanship of David Williams of the University of Liverpool, UK.

During the 4-day ESB meeting, many talks focused on the potential of biodegradable materials, and of the prospects for tissue engineering. Applications such as cartilage, skin, bone and tendons were all mentioned. Different talks looked at various scaffolds and often these were applied in animal or in vitro models. Some scaffolds employed synthetic materials, while other scaffolds used combinations of natural and synthetic materials. Furthermore, other scaffolds were said to be biodegradable. Some interesting talks focused on the use of so-called ‘foreign’ biomaterials for human applications, such as spider silk and soybean. For the latter, one successful application was said to be a bone filler. While the use of such scaffolds and biomaterials do offer potential advances, it remains to be seen how soon these can be turned into actual and successful medical devices.

Another common theme, but with perhaps a little more in vitro data, was the influence of the micro- and nanotopography on the cell reaction. For example, it was postulated that consideration should be given to the concept that, to the cell, what it ‘sees’ is not so much the material of an implant, but the topography of that implant. This was one of the points raised by Richards during his award lecture. In addition, he also considered a range of interface applications, including bone fracture, soft tissue, hard tissue and air, and he pointed out that each of these offered different challenges. In all cases he stated that microscopy was crucial to aid understanding of the reaction at the implant surface, and the more techniques of microscopy that could be employed, the better.

In a session concerned with biomimetic materials and coatings, Ishihara, from the University of Tokyo, Japan, reported some remarkable results for a modified polyethylene used as the acetabular component in a total hip prosthesis. After attaching a biocompatible surface layer of 100–150 nm thickness, the modified polyethylene components were tested. In a pin-on-flat test, a 90% reduction in friction torque compared with conventional polyethylene was reported. Then, employing a multistation hip simulator, wear tests to ten million cycles were undertaken. No weight loss of the modified polyethylene components was reported. However, measurable wear was seen by cross-linked polyethylene acetabular components which were tested in parallel. These weight change results were supported by topographic studies on the tested components, which again showed no significant wear of the modified polyethylene components, but wear of the cross-linked polyethylene components. In addition ‘wear’ particles of the new modified polyethylene material were produced and used in an animal model. Compared with conventional polyethylene, the modified polyethylene was said to be ‘biologically inert’. Speaking to Ishihara afterwards, I was told that the hip simulator test is currently at 28 million cycles and still little, or no wear, was discernable. Details of this work have been published previously [1].

Another interesting talk was given by Hilborn of Lund University, Sweden, entitled ‘Cell and tissue reactions to scaffold materials’. Here he considered opportunities for applying tissue engineering to the body. He initially took a case study of a patient whose skull required a large bone graft. As solutions, the harvesting of the patient’s own bone, the transplantation of sections of the patient’s ribs and finally the growing of a bone within a mould placed within a large muscle of the patient were all tried, the latter being found to be the most successful. In all cases, the need to use the patient’s own bone and blood supply was said to be critical to the chances of success. Hilborn then went on to argue that when considering any implant, the biomechanics at the interface between the implant and the cells is a key factor determining the amount of fibrotic capsule formation in response to the implant. He offered the opinion that the biomechanics and stresses at the interface, due to the different values of Young’s modulus, are more important than surface chemistry. He stated that if cells are mechanically overstressed, then they rupture and die. Therefore, he argued that such high stresses on cells should be avoided and biomaterials should have a close modulus match to the natural tissue they are replacing. Furthermore, as with previous speakers, he focused on the implant topography. He cited an example based on a rat model where a nominally rougher implant surface resulted in a smaller fibrotic capsule compared with a ‘smooth’ surface. In turn, he wondered whether the ‘rougher’ surface might offer better stress distribution, from the implant to the tissue, than the ‘smoother’ surface.

In conclusion, the 19th European Conference on Biomaterials offered some fascinating glimpses of advances in biomaterials which could play an important part in the medical devices of the future. The Society’s next meeting will take place in Nantes, France between the 27th and 30th September 2006.