Paper Title:

Molecular Modeling and Experimental Investigation of Hydrolytically Degradable Polymeric Biomaterials

Periodical Advances in Science and Technology (Volume 76)
Main Theme 5th FORUM ON NEW MATERIALS PART E
Edited by Pietro VINCENZINI, John A. JANSEN, Kazuhiko ISHIHARA and Thomas J. WEBSTER
Pages 16-24
DOI 10.4028/www.scientific.net/AST.76.16
Citation Dieter Hofmann et al., 2010, Advances in Science and Technology, 76, 16
Online since October, 2010
Authors Dieter Hofmann, Maria Entrialgo, Jürgen Reiche, Karl Kratz, Andreas Lendlein
Keywords Biomaterial Hydrolytic Degradation, Langmuir Monolayer, Molecular Modeling, Polymer
Article Preview
View full size
Abstract

Biodegradable polymers are applied in temporary implants, such as surgical sutures and controlled drug delivery systems. They are also of relevance in biomaterial-based Regenerative Therapies, where they provide a temporary substitute of the extra-cellular matrix. A major limitation of established degradable implant materials is the fact, that their degradation behavior can not be reliably predicted applying existing experimental methodologies. Therefore a knowledge-based approach is clearly needed to overcome this problem and to enable the tailored design of biodegradable polymers. Here we describe two methods, which can be applied in this approach: molecular modeling combining atomistic bulk and interface models with quantum chemical studies and experimental investigations of macromolecule degradation in Langmuir monolayers. The polymers utilized to exemplarily illustrate the concepts are aliphatic (co)polyesters [e.g. poly(-caprolactone) (PCL), polyglycolide (PGA), poly(rac-lactide) (PDLLA), poly[(rac-lactide)-co-glycolide] (PLGA)] and copoly(ether)esteruretanes as multiblock copolymers. The molecular modeling approach permits to efficiently investigate the influence of micro-structural properties like free volume distribution, cohesive energy density and concentration of polar functional groups on the bulk water uptake as one constituent part of hydrolytic degradation. The Langmuir monolayer investigations on polymer degradation on the other hand yield the dynamics of bond splitting during degradation within hours separately from time consuming diffusion processes, which may take months in bulk samples.