Special Issue "Advances in Biomaterials"

Guest Editor
Prof. Dr. Heather Sheardown
Scientific Director, 20/20 NSERC Network for the Development of Ophthalmic Materials, Department of Chemical Engineering, McMaster University, Canada
Website: http://chemeng.mcmaster.ca/sheardown.html
E-Mail:
Interests: biomaterials; tissue engineering; mathematical modeling of physiologic processes; ophthalmic drug delivery

Dear Colleagues,

Please accept this invitation to submit a manuscript for a special issue of Materials entitled "Advances in Biomaterials". This special issue will provide the community with the opportunity to present the latest fundamental and applied biomaterials research to the broader materials community. Materials publishes manuscripts which advance the in-depth understanding of the relationship between the structure, the properties or the functions of all kinds of materials and covers all aspects of biomaterials research. This special issue will facilitate interactions between the biomaterials community and the broader materials communities.

Prof. Dr. Heather Sheardown
Guest Editor

Submission

All papers should be submitted to materials@mdpi.org. To be published continuously until the deadline and papers will be listed together at the special website.

Submitted papers should not have been published previously, nor be under consideration for publication elsewhere. All papers are refereed through a peer-review process. A guide for authors is available on the Instructions for Authors page. Materials is an international peer-reviewed quarterly journal published by Molecular Diversity Preservation International. Review manuscripts: Before writing their manuscripts, potential authors of review articles should forward the title and a short abstract to materials@mdpi.org. We will then provide feedback on the suitability of the topic.

Open Access publication fees are 300 CHF per paper. English correction fees and/or formatting fees (250 CHF) will be added in certain cases (550 CHF per paper for those papers that require extensive additional formatting and/or English corrections).

Starting 1 January 2010, Article Processing Charges are of 800 CHF per accepted article for Materials.

• polymers
• metals
• ceramics
• protein material interactions
• cell material interactions
• surface modification

Regular Paper:

Type of Paper: Review
Title: Synthesis and Bioactivity of Bioceramics and Glass Ceramics
Authors: Hande Demirkiran and Pranesh B. Aswath
Affiliations: Materials Science and Engineering Department, University of Texas at Arlington, TX 76019, USA
Abstract: Bioceramics include bioinert ceramics such as alumina and zirconia and bioactive ceramics such as phosphate based ceramics. Bioactive glass such as phosphate based glasses and silicate based glasses have found increasing applications in applications such as orthopedic and maxillofacial structures. In this review processing of bioceramics is examined from nanoparticles to structural bioceramics. Analytical techniques used to characterize material properties and biological activity of bioceramics and glass ceramics both in vivo and in vitro are examined. The role played by chemistry, morphology, microstructure and grain size on bioactivity is reviewed.

Type of Paper: Review
Title: Biodegradable Microfluidics for Tissue Engineering
Authors: Christopher J. Bettinger¹ and Jeffrey T. Borenstein²
Affiliations: ¹ Department of Chemical Engineering, Stanford University, 381 North-South Mall, Stauffer III Room 112, Stanford, CA
² Biomedical Engineering Center, Draper Laboratory, Mail Stop 32, 555 Technology Square, Cambridge, MA, USA
Abstract: There has been an expanded role for the micro- and nanofabrication of biomaterials for use in tissue engineering and regenerative medicine. Engineered microvascular networks have demonstrated broad utility in advancing regenerative medicine by improving the functionality of biodegradable scaffolds. For example, the use of biodegradable microfluidics has been demonstrated to precisely control cellular microenvironments, guide nascent tissue formation, and overcome issues of mass transport limitations. This article will outline materials selection, fabrication strategies, and design considerations involved in the realization of microfluidic biomaterials for tissue engineering applications. The future of microfluidic devices for regenerative medicine applications will also be discussed.

Type of Paper: Review
Title: Poly(ethylene glycol): Lost in Translation
Authors: A. J. Andersen, S. H. Hashemi and S. M. Moghimi
Affiliation: Centre for Pharmaceutical Nanotechnology and Nanotoxicology, Department of Pharmaceutics and Analytical Chemistry, University of Copenhagen, Universitetsparken 2, DK2100, Copenhagen Ø, Denmark.
Abstract: Poly(ethylene glycol), PEG, is often perceived to be biocompatible and immunologically safe, and therefore is used widely in the engineering and development of biomaterials and nanomedicines. PEG, has also been identified as a therapeutic agent per se in a variety of experimental settings to include spinal cord injury and traumatic axonal brain injury. However, recent studies have shown that both soluble PEG and PEG-grafted surfaces can trigger complement activation in human serum. PEG-mediated generation of complement anaphylatoxins may provide a plausible explanation to the previously reported unexplained anaphylaxis or the referred cardiovascular collapse in animals and sensitive individuals' that have received PEG and PEG-based nanomedicines intravenously. We critically assess complement activation by PEG and related polymers, and explore the likely mechanisms.

Type of Paper: Article
Title: Biomimetic Scaffolds Engineered to Promote Nerve Regeneration after a Spinal Cord Injury
Authors: Joanne M. Hackett and May Griffith
Affiliation: University of Ottawa Eye Institute, Ottawa Hospital Research Institute, The Ottawa Hospital, General Campus, 501 Smyth Road, Suite W3803, Ottawa, Ontario K1H 8L6, Canada
Abstract: To reverse the devastating effects of SCI, an interdisciplinary approach that combines material science and engineering, stem cell biology and neurosurgery is being carried out. We are currently investigating a scaffold that has the ability to deliver growth factors for the proliferation and differentiation of endogenous stem cells. Mouse and rat neurospheres are being used to assess the efficacy of the release of growth factors in vitro. Rats have been implanted with a tubular implant and assessed with functional locomotor testing, electrophysiology and histology to determine therapeutic efficacy.

Type of Paper: Article
Title: Apatite-Nanodiamond Composite Coating of Metals. Interaction with Fibronectin and Osteoblast-Like Cells
Authors: E. Pecheva¹, L. Pramatarova¹, K. Hristova², G. Altankov^3,4, T. Hikov¹, D. Fingarova¹, Y. Tanaka⁵, H. Sakamoto⁵, H. Doi⁵, Y. Tsutsumi⁵, T. Hanawa⁵
Affiliations: ¹ Laboratory of Biocompatible Materials, Institute of Solid State Physics, Bulgarian Academy of Sciences, 72, Tzarigradsko Chaussee blvd., 1784 Sofia, Bulgaria; E-Mail: emily@issp.bas.bg (E. P.)
² Institute of Biophysics, Bulgarian Academy of Sciences, Acad. G. Bonchev str., bl. 21, 1113 Sofia, Bulgaria
³ ICREA (Institucio Catalana de Recerca i Estudis Avançats), Passeig Lluís Companys, 23, 08010 Barcelona, Spain
⁴ Institute for Bioengineering of Catalonia (IBEC), Campus de Bellvitge-Feixa Llarga/Pavelló Govern 1a, 08907 L'Hospitalet de Llobregat, Barcelona, Spain
⁵ Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 101-0062 Tokyo, Japan
Abstract: Homogeneous nanodiamond-reinforced apatite (AP-ND) composite coating with improved mechanical strength, surface adhesion, interlayer cohesion and ductility was developed to improve the biological properties of metal surfaces. Study of the initial cell adhesion and spreading of osteoblast-like MG-63 cells revealed that cells attached well but poorly spread to all samples (AP-ND, pure AP and stainless steel surfaces). Even at small concentrations (1 μg/ml), pre-coating with fibronectin (FN) strongly improved adhesion and spreading preferentially on AP-ND samples as indicated by the flattened cell morphology and pronounced vinculin positive focal adhesions. Cells tended to rearrange adsorbed FN in a fibril-like pattern, better pronounced on AP-ND.

Type of Paper: Article
Title: The Effect of Trace-Level Calcium-Based Impurities on the In Vitro Mineralisation of Polycaprolactone
Authors: Edeline Wentrup-Byrne^1,2 and John Colwell²
Affiliations: ¹ Tissue Repair & Regeneration Program, Queensland University of Technology, Brisbane, Queensland 4001, Australia
² School of Physical and Chemical Sciences, Queensland University of Technology, Brisbane, Queensland 4001, Australia
Abstract: A series of PCL/PEG/PCL triblock copolymers intended for bone repair applications were synthesised using a biocompatible calcium initiator. Calcium initiator residues have the potential to increase the bioactivity of PCL materials in vivo through enhanced formation of calcium phosphate (CaP) minerals. The effect that the calcium-initiator residues in our PCL/PEG/PCL triblock copolymers had on in vitro mineralisation was studied using simulated body fluid (SBF). The residues were identified, by Fourier transform infrared-attenuated total reflectance spectroscopy (FTIR-ATR), as a mixture of calcium hydroxide (Ca(OH)₂) and calcium carbonate (CaCO₃). A model study in SBF was performed concurrently: PCL homopolymer was doped with low concentrations (0.2 – 2 w / w % Ca) of Ca(OH)₂, or CaCO₃. SEM/EDX analysis showed the presence of CaP mineral on Ca(OH)₂-doped PCL but not on CaCO₃-doped PCL. This was attributed to the higher solubility of Ca(OH)₂, compared to CaCO₃. Although CaP deposition has never been reported for untreated PCL and PCL/PEG/PCL, some CaP deposition was observed on our PCL/PEG/PCL triblock copolymers and attributed to the low concentration of the initiator residue, Ca(OH)₂. In conclusion, calcium initiator residues were found to have the potential for increasing the bioactivity of PCL-based materials.

Type of Paper: Review
Title: Polymeric Microspheres for Medical Applications
Authors: K. Saralidze, L.H. Koole and M.L.W. Knetsch
Affiliation: Dept. Biomaterials/Biomedical Technology, University of Maastricht/ FdHML, Universiteitssingel 50, 6229 ER Maastricht, The Netherlands; E-Mail: Menno.Knetsch@BIOCH.unimaas.nl
Abstract: Synthetic polymeric microspheres find application in a wide range of medical applications. Among others microspheres are being used as bulking agents, embolic- or drug-delivery particles. The exact composition of the spheres varies with the application and therefore a large array of materials has been used to produce microspheres. In this review the relation between chemical composition and application is discussed for a number of different microspheres that are used for different treatment strategies.

Type of Paper: Article
Title: Versatile Biodegradable Poly(Ester Amide)s Derived from α-Amino Acids for Tissue Engineering Applications
Authors: Pooneh Karimi, Amin S. Rizkalla and Kibret Mequanint
Affiliation: Department of Chemical and Biochemical Engineering, The University of Western Ontario, London, ON, Canada; E-Mail: kmequani@eng.uwo.ca
Abstract: Biodegradable poly(ester amide) (PEA) biomaterials derived from α-amino acids, diols, and diacids are promising materials for biomedical applications such as tissue engineering and drug delivery because of their optimized properties and susceptibility for either hydrolytic or enzymatic degradation. The objective of this work was to synthesize and characterize biodegradable PEAs based on the α-amino acids L-phenylalanine and L-methionine. Four different PEAs were prepared using 1,4-butanediol, 1,6-hexanediol, and sebacic acid by interfacial polymerization. High molecular weight PEAs with narrow polydispersity indices and excellent film-forming properties were obtained. The incubation of these PEAs in PBS and chymotrypsin indicated that the polymers are biodegradable. The GPC analyses before and after incubation suggested that the L-phenylalanine-based PEAs undergo predominantly a surface erosion mechanism whereas L-methionine PEAs degrade by a combination of bulk and surface erosion mechanism. Human coronary artery smooth muscle cells were cultured on films for 48 h and the results showed a well-spread morphology indicating the potential utility of these polymers as potential biomaterials. Porous 3D scaffolds fabricated from these PEAs were also found to have excellent porosities for potential tissue engineering applications.
Keywords: biodegradable polymers; α-amino acids; poly(ester amide)s; interfacial polymerization; scaffolds