Enhanced osteogenic differentiation with 3D electrospun nanofibrous scaffolds.
ABSTRACT Aim: Developing 3D scaffolds mimicking the nanoscale structure of the native extracellular matrix is important in tissue regeneration. In this study, we aimed to demonstrate the novelty of 3D nanofibrous scaffolds and compare their efficiency with 2D nanofibrous scaffolds. Materials & methods: The 2D poly(L-lactic acid)/collagen nanofibrous scaffolds were 2D meshes fabricated by the conventional electrospinning technique, whereas the 3D poly(L-lactic acid)/collagen nanofibrous scaffolds were fabricated by a modified electrospinning technique using a dynamic liquid support system. The morphology, proliferation and differentiation abilities of human mesenchymal stem cells in osteogenic medium on both scaffolds were investigated. Results & conclusion: Compared with the 2D scaffolds, the 3D scaffolds significantly increased the expression of osteoblastic genes of the stem cells as well as the formation of bone minerals. In addition, the scanning electron microscopic and micro-computed tomographic images showed the dense deposition of bone minerals aligned along the nanofibers of the 3D scaffolds after 14 and 28 days cultured with the mesenchymal stem cells. As such, the 3D electrospun poly(L-lactic acid)/collagen nanofibrous scaffold is a novel bone graft substitute for bone tissue regeneration. Original submitted 17 November 2011; Revised submitted 21 February 2012.
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ABSTRACT: Bone regeneration strategies in dentistry utilize biodegradable scaffolds seeded with stem cells able to induce bone formation. However, data on regeneration capacity of these tissue engineering constructs are still deficient. In this study micro-Computed tomography (micro-CT) and positron emission tomography (PET) analyses were used to investigate bone regeneration induced by two scaffolds [Granular deproteinized bovine bone (GDPB) and Beta-tricalcium phosphate (β-TCP)] used alone or in combination with dental pulp stem cells (DPSC) in a tissue engineered construct implanted in a rat critical calvarial defect. Bone mineral density (BMD) and standard uptake value (SUV) of tracer incorporation were measured after 2, 4, 8, and 12 weeks post-implant. The results showed that: (1) GDPB implants were mostly well positioned, as compared to ß-TCP; (2) GDPB induced higher BMD and SUV values within the cranial defect as compared to ß-TCP, either alone or in combination with stem cells; (3) addition of DPSC to the grafts did not significantly induce an increase in BMD and SUV values as compared to the scaffolds grafted alone, although a small tendency to increase was observed. Thus our study demonstrates that GDPB, when used to fill critical calvarial defects, induces a greater percentage of bone formation as compared to ß-TCP. Moreover, this study shows that addition of DPSC to pre-wetted scaffolds has the potential to ameliorate bone regeneration process, although the set of optimal conditions requires further investigation. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013.Journal of Biomedical Materials Research Part B Applied Biomaterials 10/2013; · 2.31 Impact Factor
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ABSTRACT: In regenerative medicine studies, cell seeding efficiency is not only optimized by changing the chemistry of the biomaterials used as cell culture substrates, but also by altering scaffold geometry, culture and seeding conditions. In this study, the importance of seeding parameters, such as initial cell number, seeding volume, seeding concentration and seeding condition is shown. Human mesenchymal stem cells (hMSCs) were seeded into cylindrically shaped 4 × 3 mm polymeric scaffolds, fabricated by fused deposition modelling. The initial cell number ranged from 5 × 104 to 8 × 105 cells, in volumes varying from 50 µl to 400 µl. To study the effect of seeding conditions, a dynamic system, by means of an agitation plate, was compared with static culture for both scaffolds placed in a well plate or in a confined agarose moulded well. Cell seeding efficiency decreased when seeded with high initial cell numbers, whereas 2 × 105 cells seemed to be an optimal initial cell number in the scaffolds used here. The influence of seeding volume was shown to be dependent on the initial cell number used. By optimizing seeding parameters for each specific culture system, a more efficient use of donor cells can be achieved. Copyright © 2013 John Wiley & Sons, Ltd.Journal of Tissue Engineering and Regenerative Medicine 11/2013; · 4.43 Impact Factor
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ABSTRACT: Many scaffold systems have evolved for tissue engineering and in vitro tissue models to provide a 3D (three-dimensional) microenvironment that enables cells to behave more physiologically. We hypothesized that cells would adopt morphologies with more 3D character during culture in scaffolds as compared to planar substrates. Cell shape and function are tightly linked and effects of scaffold niche properties on cell shape and dimensionality are important for directing cell function. Herein, primary human bone marrow stromal cells (hBMSCs) were cultured in 6 different scaffolds and on a planar control substrate. hBMSCs were imaged using 3D confocal microscopy, and 3D image analyses were used to assess hBMSC shape and dimensionality. A characteristic gyration tensor ellipsoid was calculated for hBMSCs in the different scaffolds which enabled hBMSC dimensionality to be classified based on shape. A "Dimensionality Matrix" was developed that showed that hBMSC shape and dimensionality were influenced by scaffold properties, and that scaffolds could drive hBMSCs into 1D, 2D or 3D shapes. In addition, the hBMSC Z-Depth was measured to determine if hBMSCs became less flat during culture in scaffolds. Z-Depth results showed that all 6 scaffolds caused an increase in cell Z-Depth compared to the 2D planar substrate. These results demonstrate that hBMSCs take on morphologies with greater 3D character in scaffolds than on a planar substrate and that scaffold properties can be adjusted to modify cell dimensionality. In addition, biomaterialists can use this measurement approach to assess and compare scaffold design modifications as they strive to create optimal cell niches that provide a 3D microenvironment.Biomaterials 01/2014; · 8.31 Impact Factor