Browsing by Author "Walboomers, X. Frank"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
Item Effect of nanotubes and apatite on growth factor release from PLLA scaffolds(2011-06) Zande, Meike van der; Walboomers, X. Frank; Olalde, Beatriz; Jurado, Maria J.; Álava, J. Iñaki; Boerman, Otto C.; Jansen, John A.; Biomateriales; Tecnalia Research & InnovationThere is an evident clinical need for artificial bone restorative materials. In this respect, novel composites based on poly(L-lactic acid) (PLLA) have been described. The bone response of such polymer-based composites is usually improved by the addition of bone morphogenetic protein-2 (BMP-2). However, released BMP-2 is cleared almost immediately from the site of implantation by diffusion, whereas a prolonged retention of BMP-2 onto the scaffold has been suggested to be more favourable. Besides the ability to improve the mechanical strength and osteoconductivity of polymeric scaffolds, both carbon nanotubes (CNTs) and microhydroxyapatite (μHA) have been described to facilitate such retention of BMP-2 when incorporated into a composite scaffold. Therefore, in the current study, radiolabelled BMP-2 was loaded onto plain PLLA and composite PLLA-CNT-μHA scaffolds. Subsequently, the scaffolds were implanted subcutaneously for 5 weeks in rats and BMP-2 release was measured. Release started with an initial phase of quick release, followed by a gradual release of BMP-2. Both scaffold types comprised the same in vivo release properties for BMP-2. The bioactivity of the BMP-2 remained unaltered. It can be concluded that incorporated CNTs and μHA did not affect BMP-2 release from composite scaffold materials.Item Genetic profiling of osteoblast-like cells cultured on a novel bone reconstructive material, consisting of poly-l-lactide, carbon nanotubes and microhydroxyapatite, in the presence of bone morphogenetic protein-2(2010-11) Van Der Zande, Meike; Walboomers, X. Frank; Brännvall, Mathias; Olalde, Beatriz; Jurado, Maria J.; Álava, J. Iñaki; Jansen, John A.; Biomateriales; Tecnalia Research & InnovationIn bone tissue engineering composite materials have been introduced, combining a degradable polymer matrix with, for instance, carbon nanotubes (CNTs) to improve mechanical properties or with microhydroxyapatite (μHA) to improve osteoconduction. The addition of bone morphogenetic protein-2 (BMP-2) can further improve the biological response to the material. However, the influence of such an elaborate composite formation on osteoprogenitor cells is unknown. To examine this, rat bone marrow (RBM) cells were cultured on porous poly-l-lactic acid and composite scaffolds, with or without added BMP-2. Cell proliferation and differentiation were studied using DNA, alkaline phosphatase and scanning electron microscopic analysis. Further, genetic profiles were examined by microarray investigation. Results showed that the composite scaffold had no significant effect on the proliferation of RBM cells, but indicated a negative effect on cell differentiation. The addition of BMP-2 also had no significant effect on the proliferation of RBM cells, but differentiation towards the osteogenic lineage was confirmed. In the arrays results, the addition of BMP-2 alone led to the expression of genes involved in (minor) inflammation. The composite scaffold, and even more distinctly the combination of the composite scaffold with BMP-2, led to the expression of genes, based on gene ontology, connected to tumorigenesis. Therefore, CNT- and μHA-containing composite materials are not recommended as a bone restorative material.