Nanophase Alumina/Poly(L-Lactic Acid) Composite Scaffolds for Biomedical Applications
- PDF / 425,717 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 4 Downloads / 191 Views
I6.3.1
Nanophase Alumina/Poly(L-Lactic Acid) Composite Scaffolds for Biomedical Applications Aaron J. Dulgar Tulloch1,3, Rena Bizios2,3, and Richard W. Siegel1,3 Department of Materials Science and Engineering, 2Department of Biomedical Engineering, and 3 Rensselaer Nanotechnology Center Rensselaer Poytechnic Institute, Troy, NY 12180-3590 USA 1
Abstract Three-dimensional composites of nanophase alumina and poly(L-lactic acid) with an interconnected porous network and an overall porosity in excess of 90% are cytocompatible. Osteoblast proliferation on the nanophase ceramic/polymer composites is a function of time of cell culture and of nanoceramic loading in the biomaterial substrates. Introduction Biomaterials are an integral part of biomedical applications, such as tissue engineering and prosthetic devices, that constitute alternative strategies in addressing the increasing clinical need for replacement tissue. Such materials also provide the potential for alleviating the limitations of autologous tissue availability and the medical problems associated with allografts. Among the most promising recent biomaterial developments, nanophase ceramics and their composites with polymers have been shown to exhibit selectivity for, and promoted enhancement of, osteoblast (the bone-forming cell) functions pertinent to new bone tissue formation.1-6 To date, however, the potential of these novel material formulations has only been explored using essentially two-dimensional substrates. Because of the three-dimensional nature of native tissues, and of the pertinent construction requirements for tissue engineering applications, the current study focused on the preparation, characterization, and cytocompatibility of three-dimensional nanophase alumina/poly(L-lactic acid) composite scaffolds in an effort to provide improved material formulations for biomedical applications. Materials and Methods Scaffold Preparation Three-dimensional, porous composite scaffolds were prepared using a thermal phase separation process according to established methods.7 Briefly, poly(L-lactic acid) (PLLA) with a molecular weight of 100,000 (Polysciences) was dissolved in 1,4-dioxane (Sigma-Aldrich) by magnetic stirring at 70 oC for two hours to obtain a 5% (w/v) solution. Appropriate amounts of either nanophase alumina (grain size of 38 nm; Nanophase Technologies) or micron-size alumina (grain size of 1 µm; Sigma-Aldrich) were blended into the polymer solution by vortexing and then stirring at 70 oC for one hour to obtain 50/50, 60/40, 70/30, or 80/20 (w/w) percent ceramic/polymer composites. Each composite was frozen at –20 o C for 2 hours and then at –70 oC overnight, before being freeze-dried at -98 oC and 7 mTorr for 48 hours (to remove the dioxane). All scaffolds were stored in a dessicator for a maximum of 7 days prior to use. Pure PLLA scaffolds were constructed similarly, but without the addition of ceramic, and were used as controls.
I6.3.2
Scaffold Architecture and Properties Scaffolds (12.5 mm in diameter and 25.0 mm in height) were cut
Data Loading...
