It is our utmost pleasure to complete this special issue in honour of Professor William Bonfield CBE, FRS, FREng, FMedSci and founding editor of this journal, by writing this Introduction to the second part, which is broadly dedicated to the theme of Tissue Engineering. The first part on Particles and Drug Delivery was published as the August 2010 issue (volume 7, supplement 4, 2010).
Once again, a rich collection of papers written by internationally leading researchers, covering the processing/forming, microstructure and properties of several bio- and medical materials is included in this issue. These papers contain many examples of the concept to patient ideology, which is a key feature of Professor Bonfield's pioneering research. In their contribution, Kokubo et al. (2010) report a new principle where a positively charged surface is used to obtain a bioactive material. They demonstrate this principle by forming apatite on a positively charged titanium surface. Palmquist et al. (2010) discuss the surface characteristics, interfacial biology and clinical outcomes of titanium oral implants. They show the crucial importance of the surface properties, indicating the challenges faced and commenting on the lack of information on the role of specific surface properties, e.g. nanoscale features, on in vivo performance.
Biomaterials remain the key building blocks of tissue engineering. Using hydroxyapatite (HA)–carbon nanotube composites, White et al. (2010) show how the sintering atmosphere can be optimized to prepare high-density structures from these materials, with improved mechanical properties compared with HA. This is an important development as stronger and tougher biomaterials are vital for many applications in tissue engineering. Tanner (2010) focuses on HA-reinforced polyethylene, a material she developed building on Professor Bonfield's work, and revolutionizing the biomaterials and tissue engineering arena in the process. This material exemplifies another concept to the patient success story, as it has been applied clinically, including in the middle-ear. Ravichandran et al. (2010) report on conducting polymers, discussing various surface modifications that can promote the most important aspects of cell adhesion and cell proliferation at the polymer–tissue interface. Developing these materials has greatly enhanced the choice of medical materials for tissue engineering. Boccaccini et al. (2010) show how a specific process, electrophoretic deposition (EPD), is becoming increasingly attractive for the preparation of biomedical structures vital for successful tissue engineering. For some time now, EPD has been a hot topic in the materials processing and forming community, but the authors take it to another level by including biological entities such as enzymes, bacteria and cells in their research. The paper by Duan & Wang (2010) includes design, fabrication, surface modification of scaffolds and sustained release of growth factor included in the scaffold. Thus, they show the thinking behind the development of customized nanocomposite scaffolds for bone tissue engineering. They use selective laser sintering rapid prototyping technology and osteo-conductive nanocomposite materials to prepare complex scaffolds with controlled porosity and an interconnected porous structure. From their conclusions it can be deduced that this route may be of great promise in ‘scaling the heights’ in order to address the challenges facing medical materials. In their paper, Liu et al. (2010) focus on biomimetic coatings and their use in bone tissue engineering repairs of critical size defects, crucially important in dental implants, maxillofacial surgery and orthopaedics. Tzeranis et al. (2010) quantify the density of ligands and adhesion receptors in three-dimensional matrices that surround cells. This is done using an optical method and provides initial results for collagen-based scaffolds, which can be used to mimic medical materials in the clinical regeneration of injured skin and peripheral nerves. In their paper, Ehrenfried et al. (2010) demonstrate the use of synchrotron micro-computer tomography to study in detail the degradation of ceramic–polymer composites, finding that the degradation was very sensitive to the manufacturing method.
As in the first issue, we are extremely grateful to all the authors for contributing these papers, which describe some of their current cutting edge research. In addition to the scientific contribution, these works demonstrate how communities worldwide can be helped by research to ‘scale the heights’ in order to speedily tackle the challenges faced in medical materials, from concept to patient.
One contribution to a Theme Supplement ‘Scaling the heights—challenges in medical materials: an issue in honour of William Bonfield, Part II. Bone and tissue engineering’.
- Received July 7, 2010.
- Accepted July 7, 2010.
- © 2010 The Royal Society