Nanostructured surfaces for bone biotemplating applications

Abstract

A major goal of orthopedic biomaterials research is to design better surface chemistries and configurations to control behavior of bone cells such as osteoblasts. Nanostructured architecture significantly affects the response of several cell lines. In this work, nanostructured surfaces were prepared by vapor liquid solid growth of silicon nanowires from size-controlled gold colloid catalysts deposited on fused silica substrates. The lengths and surface densities of the nanowires were varied to assess the effect of these parameters on bone cell response. Osteoblasts were seeded on nanowire surfaces to investigate both short-term adhesion and proliferation and long-term functionality and matrix production. Cell adhesion and proliferation were characterized using a standard 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide assay and cell counting for up to 4 days of culture. The total protein content, alkaline phosphatase activity, and matrix production were quantified using standard colorimetric assays for up to 4 weeks of culture. Matrix production was also characterized by measuring surface concentrations of calcium and phosphorus using X-ray photoelectron spectroscopy. Further, scanning electron microscopy was used to investigate osteoblast morphology on nanostructured surfaces. Over the 4-week study, the nanostructured surfaces demonstrated improved osteoblast adhesion and proliferation and increased alkaline phosphatase activity and matrix production compared to non-nanostructured control surfaces.

Bone tissue engineering: A review in bone biomimetics and drug delivery strategies

“…In recent years, it has been well established in the literature that bone cells are profoundly influenced by topography in vitro. 11,107,[179][180][181][182] The microscale features of bone provide a conduit for vascularization, nutrient delivery, and cell migration. Several researchers have suggested that for a bone cell and nutrients to migrate into a scaffold, the pores should be at least the size of the cell.…”

“…Examples of successful 2D and 3D nanofabrication techniques include electrospinning, [195][196][197][198][199] nanotemplating, 179,200 electrostatic spray deposition, 201,202 RF plasma spray/deposition, 203 molecular self assembly, [204][205][206] and metal oxide anodization. 104,182,[207][208][209] Of the fabrication techniques listed above, electrospinning has emerged as a very promising strategy for fabricating bone-mimetic nanofiber scaffolds. The popularity of electrospinning is likely due to the simplicity of the experimental setup, the ability to incorporate bioactive molecules, and the versatility is provides.…”

“…Template synthesis is a simple procedure which provides a controlled approach for developing nanoscale polymer constructs for tissue engineering applications. 182,213 In template synthesis, a polymer is heated above its melting temperature and gravimetrically extruded into a nanopore membrane which is subsequently removed leaving the negative template of nanowires ( Figure 7). Recently, substrate-bound arrays of poly(caprolactone) (PCL) nanowires were synthesized using this technique.…”

“…195,214,215 Templating is another fabrication technique which is capable of developing multidimensional structures. 104,182,200,213 Other techniques such as modified rapid prototyping, 216 electrochemical anodization, template synthesis, and polymer-mineral emulsion have also demonstrated the ability to construct multiscale synthetic scaffolds.…”

Biomaterials and Biotechnology Schemes Utilizing TiO2 Nanotube Arrays

“…In other research groups studying nanoporous materials, www.intechopen.com major accomplishments have been made in the generation of geometrically defined surfaces with the fabrication of Al and Si nanostructured surfaces. There is rapidly increasing evidence that the lateral spacing of features on the nanoscale can impact and change cell behaviour (Boyen et al 2002;Cavalcanti-Adam et al 2006;Popat et al 2006). Therefore, in order to optimize the lateral spacing of the TiO 2 nanotube system, by changing the geometry of the nanotubes, four different pore sizes (30, 50 70, and 100nm in diameter) were created ( Figure 2) for examination of cartilage chondrocyte cells, bone osteoblast cells, and osteoprogenitor mesenchymal stem cells.…”