Special Issue "Biodegradability of Materials in Biomedical Applications 2011"

Guest Editor
Prof. Dr. Aldo R. Boccaccini
Institute of Biomaterials, Department of Materials Science and Engineering, University of Erlangen-Nuremberg, 91058 Erlangen, Germany
Website: http://www.biomat.techfak.uni-erlangen.de
E-Mail:
Phone: +44 207 594 6731
Fax: +44 207 594 6757
Interests: biomaterials; porous materials; scaffolds; tissue engineering; composite materials; bioactive glasses; ceramics; waste recycling; carbon nanotubes; electrophoretic deposition

Guest Editor
Prof. Dr. Showan N. Nazhat
Department of Mining and Materials Engineering, McGill University, Montreal, Canada
E-Mail:

Dear Colleagues,

New generation biomaterials should be able to stimulate specific cellular responses at the molecular level, moving from the concept of inertness to one of bioactivity, e.g. positive interaction at the biomaterial-tissue interface. In many cases the body needs only the temporary presence of a device or implant, in which case fully or partially biodegradable materials are better alternatives than biostable materials. The ideal biodegradable material – polymer, ceramic, metal or composite - should be biocompatible, provide adequate initial mechanical fixation, controllably degradable, and should ultimately be replaced by the regenerated tissue.

A wide range of biodegradable materials is being continuously investigated for biomedical applications, which include traditional and advanced biodegradable polymers, bioceramics and composites as well as a small group of metals and alloys based on magnesium.

Typical applications and research areas of biodegradable polymers include surgery sutures, wound dressing, antibacterial coatings, fixation devices, tissue engineering scaffolds as well as drug and cell delivery platforms. Current research focuses also on the development of biodegradable composites combining synthetic or natural biodegradable polymers and bioactive inorganic fillers, e.g. bioactive glasses and calcium phosphate ceramics, which mimic the structural characteristics of the natural extracellular matrix. Magnesium alloys are promising candidates for several structural biomedical applications due to their degradation ability combined with appropriate mechanical properties as well as good biocompatibility and are being proposed as cardiovascular stents, bone fixation devices and porous bone repair materials.

The present combined special issue in IJMS/Materials will include papers authored by researchers around the world reporting on cutting-edge results in the broad field of biodegradable materials for biomedical applications.

Prof. S. N. Nazhat
Prof. A. R. Boccaccini
Guest Editors

Related Special Issue

Biodegradability of Materials 2011 in Materials

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• biodegradable polymers
• magnesium alloys
• bioactive glasses
• calcium phosphates
• composites
• tissue engineering
• drug delivery
• sutures
• wound dressing
• coatings
• degradable stents

Type of Paper: Article
Title: Characterization and Degradation Behavior of Agar–Carbomer Hydrogels for Drug Delivery Applications: Solute Effect
Authors: Filippo Rossi, Marco Santoro, Tommaso Casalini, Maurizio Masi and Giuseppe Perale
Affiliation: Dipartimento di Chimica, Materiali e Ingegneria Chimica “Giulio Natta”, Politecnico di Milano, Via Mancinelli 7, 20131 Milano, Italy;
E-Mail: giuseppe.perale@polimi.it (G.P.)
Abstract: In this study hydrogels composed primarily from Agarose and Carbomer 974P, were selected for their potential application in tissue engineering. Indeed, in this research field, one of the most important issues to be addressed regards hydrogel ability to provide a finely controlled delivery of different loaded drugs with a coherent degradation profile. Nevertheless, solute effects on drug delivery system are often neglected as the majority of studies are focused only on the characterization of unloaded matrices. Hence, in this work, hydrogels were loaded with different solutes and their effects were investigated both from a structural and a rheological point of view. Furthermore, degradation chemistry was assessed by means of infrared bond response (FT-IR), calorimetry (TGA) and mass loss.

Type of Paper: Article
Title: Structural Characterization of PLLA and PGA Oligomers in Water
Authors: Tommaso Casalini, Filippo Rossi, Marco Santoro and Giuseppe Perale
Affiliation: Dipartimento di Chimica, Materiali e Ingegneria Chimica “Giulio Natta”, Politecnico di Milano, Via Mancinelli 7, 20131 Milano, Italy;
E-Mail: giuseppe.perale@polimi.it (G.P.)
Abstract: Diffusion coefficients in pure water of L-lactic acid and glycolic acid were estimated through molecular dynamic simulations. Monomer structures and atomic charges were obtained with quantum chemical computation in implicit water, employing a density functional method. MD simulations were carried out in explicit water, taking into account solvent presence. A good description of diffusion phenomena can assess the suitability of the chosen force field to describe this kind of molecules. Structural characterization of PLLA and PGA oligomers was carried out with a quantum chemistry approach. Structures were first optimized using a density functional method in implicit water; rotational barriers concerning dihedral angles were then investigated. The knowledge of such energetic barriers will allow to optimize force field parameters, and thus, provide a better description of PLLA and PGA chains in aqueous environment.

Type of Paper: Review
Title: Biodegradable Metals for Cardiovascular Stent Application: Interests and New Opportunities
Authors: Maryam Moravej and Diego Mantovani
Affiliation: Laboratory for Biomaterials and Bioengineering, Department of Mining, Metallurgy and Materials Engineering & University Hospital Research Center, Université Laval, Québec City, Que. G1V 0A6, Canada; E-Mails: maryam.moravej.1@ulaval.ca (M.M.); Diego.Mantovani@gmn.ulaval.ca (D.M.)
Abstract: During the last decade, biodegradable metallic stents have been developed and investigated as alternatives for the currently-used permanent cardiovascular stents. Degradable metallic materials could potentially replace corrosion-resistant metals currently used for stent application as it has been shown that the role of stenting is temporary and limited to a period of 6-12 months after implantation during which arterial remodeling and healing occur. Although corrosion is generally considered as a failure in metallurgy, the corrodibility of certain metals can be an advantage for their application as degradable implants. The candidate materials for such application should have mechanical properties ideally close to those of 316L stainless steel which is the gold standard material for stent application in order to provide mechanical support to diseased arteries. Non-toxicity of the metal itself and its degradation products is another requirement as the material is absorbed by blood and cells. Based on the mentioned requirements, iron-based and magnesium-based alloys have been the investigated candidates for biodegradable stents. This article reviews the recent developments in the design and evaluation of metallic materials for biodegradable stents. It also introduces the new metallurgical processes which could be applied for the production of metallic biodegradable stents and their effect on the properties of the produced metals.