As we reflect on the past year, we applaud the efforts of the contributing authors and of the editorial staff, Editorial Board, and referees of Biomedical Materials (BMM), which have resulted in an increase in the journal's Impact Factor to 2.467. The importance of the papers published this past year is demonstrated in part by the increase in the number of downloads, from an average of 126 downloads per article in 2010 to 226 in 2011. And as we look ahead to 2012, highlights include focus issues on 'Injectable Hydrogels for Tissue/Organ Repair', guest edited by J A Burdick, and 'Biomaterials in Translational Regenerative Medicine', guest edited by A Atala and S J Lee. Moreover, Institute of Physics Publishing (IOPP) will be implementing the publication of future articles in BMM in an enhanced HTML format as an additional convenience for readers.

BMM remains ever attentive to maintaining the highest standards in publishing work principally focused on biomaterials fo...

Bone substitute material properties such as granule size, macroporosity, microporosity and shape have been shown to influence the cellular inflammatory response to a bone substitute material. Keeping these parameters constant, the present study analyzed the in vivo tissue reaction to three bone substitute materials (granules) with different chemical compositions (hydroxyapatite (HA), beta-tricalcium phosphate (TCP) and a mixture of both with a HA/TCP ratio of 60/40 wt%). Using a subcutaneous implantation model in Wistar rats for up to 30 days, tissue reactions, including the induction of multinucleated giant cells and the extent of implantation bed vascularization, were assessed using histological and histomorphometrical analyses. The results showed that the chemical composition of the bone substitute material significantly influenced the cellular response. When compared to HA, TCP attracted significantly greater multinucleated giant cell formations within the implantation...

Transparent poly(vinyl alcohol) (PVA) hydrogel films, derived from aqueous solutions of varying concentration, were synthesized by the cyclic freeze–thaw method (0°–37 °C). This study demonstrates a variation in the transparency, degree of crystallinity, wettability, swelling and mechanical properties of the hydrogels as a function of the solution concentration and the number of freeze–thaw cycles for a given average molecular weight (95 000 Da). The study manifests a strong control of the number of freeze–thaw cycles on the structure–property correlations of the synthesized transparent PVA hydrogels, revealing the possibility of obtaining a window of structural and process parameters for the physically cross-linked hydrogels, making them suitable for cell–gel interactions.

Polyurethanes have been widely used in medicine for coating and packaging implantable and other medical devices. Polyether-urethanes, in particular, have superior mechanical properties and are biocompatible, but in common with other medical materials they are susceptible to microbial film formation. In this study, polyether-urethane was end-capped with silver lactate and silver sulfadiazine functional groups to produce a bacterially resistant polymer without sacrificing the useful mechanical properties of the polyether-polyurethane. The silver ions were covalently incorporated into the polymer during chain extension of the prepolymer. The functionalized polymers were structurally characterized by light scattering, electron microscopy, NMR, FTIR and Raman spectroscopy. Mechanical properties, hydrophilicity, in vitro stability and antibacterial action of polymers were also investigated. Results indicate that both silver salts were successfully incorporated into the polymer s...

Bone morphogenetic protein 2 (BMP-2) is the most powerful osteogenic factor; its effectiveness in enhancing osteoblastic activation has been confirmed both in vitro and in vivo. We developed a novel peptide (designated P24) derived from the ‘knuckle’ epitope of BMP-2 and found it also had osteogenic bioactivity to some extent. The main objective of this study was to develop a controlled release system based on poly(trimethylene carbonate)–F127–poly(trimethylene carbonate) (PTMC ₁₁-F127-PTMC ₁₁) hydrogels for the P24 peptide, to promote bone formation. By varying the copolymer concentrations, we demonstrated that P24/PTMC ₁₁-F127-PTMC ₁₁ hydrogels were an efficient system for the sustained release of P24 over 21–35 days. The P24-loaded hydrogels elevated alkaline phosphatase activity and promoted the expression of osteocalcin mRNA in bone marrow stromal cells (BMSCs) in vitro. Radiographic and histological examination sh...