PubMed Health⌕ Search

PubMed · 15293407

DNA network structures on various solid substrates investigated by atomic force microscopy.

Abstract

We have fabricated DNA network structures on glass and sapphire substrates. As a comparison, we also formed the network structure on mica substrate. For titanate strontium substrate, however, DNA network can not be obtained even if it is wet-treated by Na2HPO4 solution to make it hydrophilic. We also discuss the factors that affect the DNA networks formed on various substrates.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Aiguo Wu, Zhuang Li, Erkang Wang. 2004. DNA network structures on various solid substrates investigated by atomic force microscopy.. https://doi.org/10.2116/analsci.20.1083

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

The influence of surface topography of ceramic abutments on the attachment and proliferation of human oral fibroblasts.

As different implant abutments are introduced to obtain a sufficient soft tissue barrier, the aim of this study was to determine the effect of three different surface modifications of densely sintered high-purity aluminium oxide on morphology, attachment and proliferation of human gingival fibroblasts. Fibroblasts were cultured on pressed aluminium oxide, milled, and then sintered to full density (1), on pressed, densely sintered (2), and on pressed, densely sintered and then polished surfaces (3). The different surfaces were analyzed using a confocal laser scanner, an atomic force microscope and a scanning electron microscope. The cell profile areas were measured using a semiautomatic interactive image analyzer and the figures were expressed as percent of attachment. The polished specimens had the smoothest surfaces and the roughest were the milled surfaces in terms of height deviation. No difference was found in the spacing between the peaks on the polished surfaces compared to the milled surfaces. Fibroblasts on the milled ceramic appeared to follow the direction of the fine irregularities on the surface. The analyses showed the polished surfaces had significantly higher percentages of initial cell attachment than the other surfaces (P < 0.05). After 3 days of cell culture, significantly more cells were attached to the milled and sintered surfaces than to the polished one, possibly indicating higher proliferation capacity on those types of surfaces.

Aluminum Oxide↗

Increased osteoblast functions on theta + delta nanofiber alumina.

Nanophase materials, or materials with grain sizes less than 100 nm in at least one direction, are promising materials for various implant applications since our tissues are composed of nanometer components (i.e., proteins and/or inorganics). Specifically, bone is comprised of nanostructured hydroxyapatite and collagen fibers which continuously provide an extracellular matrix surface to bone-forming cells (osteoblasts) with a high degree of nanometer roughness. Despite this fact, materials currently utilized for orthopedic implants, whether metallic or ceramic, have constituent grain sizes in the non-biologically inspired micron regime. For this reason, the objective of the present in vitro study was to determine osteoblast functions on one classification of nanomaterials for orthopedic applications: nanofiber alumina. Various crystalline forms of nanofiber alumina were tested in this study. To obtained different crystalline structured nanofiber alumina, boehmite nanofiber alumina was sintered at either 400 degrees C, 600 degrees C, 800 degrees C, 1000 degrees C, or 1200 degrees C for 2 h in air. X-ray diffraction results provided evidence that boehmite nanofiber alumina remained boehmite when sintered at 400 degrees C but changed crystalline phases to gamma, gamma + delta, theta + delta, and alpha when sintered at 600 degrees C, 800 degrees C, 1000 degrees C, and 1200 degrees C, respectively. Moreover, compared to any other alumina formulation tested in this study, osteoblast functions (as measured by alkaline phosphatase activity and calcium deposition) were the greatest on theta + delta crystalline phase nanofiber alumina after 14 days of culture. Boehmite had the next greatest amount of calcium deposition by osteoblasts followed by gamma + delta. Gamma crystalline phase then followed and was greater than alpha crystalline phase nanofiber alumina which promoted osteoblast functions the least of all the compacts with the exception of borosilicate glass (reference substrate). For this reason, this study suggests that theta+delta nanofiber alumina should be further investigated in orthopedic applications.

Aluminum Oxide↗

Effect of silicon doping on bone formation within alumina porous domains.

The effect of doping a porous bioinert bioceramic with silicon (Si) on tissue ingrowth, differentiation, and osteogenesis was studied using a rat intramedullary model. Alumina tubes (1.3-mm outer diameter, 0.6-mm inner diameter, 15-mm length) doped with Si at nominal concentrations of 0.5 and 5.0 mol % were implanted into femoral medullary canals of female rats for 16 weeks. Tissue formation within the tubes was determined by histology and histomorphometry. Addition of 0.5 mol % Si to alumina stimulated cellular activity at the bone-ceramic interface and impaired osteogenic maturation within the tubes. In contrast, osteogenesis was enhanced in the 5.0 mol % Si-doped alumina tubes. It is considered that effect of Si is related to surface chemistry rather than microstructure. This work demonstrates that doping a bioinert ceramic with small amounts of Si can significantly alter tissue ingrowth, differentiation, and osteogenesis within a porous implant.

Aluminum Oxide↗