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Journal of Nanomaterials
Volume 2014 (2014), Article ID 371307, 9 pages
http://dx.doi.org/10.1155/2014/371307
Research Article

Nanocomposites of Polyacrylic Acid Nanogels and Biodegradable Polyhydroxybutyrate for Bone Regeneration and Drug Delivery

1Department of Chemical and Biological Engineering, Chalmers University of Technology, 41296 Gothenburg, Sweden
2Ian Wark Research Institute, University of South Australia, Mawson Lakes Campus, Mawson Lakes, SA 5095, Australia
3SuMo BIOMATERIALS, VINN Excellence Center at Chalmers University of Technology, 41296 Gothenburg, Sweden

Received 26 July 2013; Accepted 22 October 2013; Published 16 January 2014

Academic Editor: Haifeng Chen

Copyright © 2014 Mikael Larsson et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Biodegradable cell scaffolds and local drug delivery to stimulate cell response are currently receiving much scientific attention. Here we present a nanocomposite that combines biodegradation with controlled release of lithium, which is known to enhance bone growth. Nanogels of lithium neutralized polyacrylic acid were synthesized by microemulsion-templated polymerization and were incorporated into a biodegradable polyhydroxybutyrate (PHB) matrix. Nanogel size was characterized using dynamic light scattering, and the nanocomposites were characterized with regard to structure using scanning electron microscopy, mechanical properties using tensile testing, permeability using tritiated water, and lithium release in PBS using a lithium specific electrode. The nanogels were well dispersed in the composites and the mechanical properties were good, with a decrease in elastic modulus being compensated by increased tolerance to strain in the wet state. Approximately half of the lithium was released over about three hours, with the remaining fraction being trapped in the PHB for subsequent slow release during biodegradation. The prepared nanocomposites seem promising for use as dual functional scaffolds for bone regeneration. Here lithium ions were chosen as model drug, but the nanogels could potentially act as carriers for larger and more complex drugs, possibly while still carrying lithium.