Biomedical Engineering Reference
In-Depth Information
marrow cells in vitro and on protein adsorption was investigated. Cell attachment,
cell proliferation, and differentiation (alkaline phosphatase specifi c activity) were
determined. The protein adsorption of bovine serum albumin and fi bronectin,
from single protein solutions on rough and smooth Ti-6Al-4V surfaces was exam-
ined with XPS and radio labeling. It was found that:
1. cell attachment and proliferation were surface roughness sensitive, and
increased as the roughness of Ti - 6Al - 4V increased,
2. human albumin was adsorbed preferentially onto the smooth substratum,
and
3. the rough substratum bound a higher amount of total protein (from
culture medium supplied with 15% serum) and fi bronectin (10 - fold) than
did the smooth one [Deligianni et al., 2001 ].
Events leading to integration of an implant into bone, and hence determining
the long-time performance of the device, take place largely at the interface
formed between the tissue and the implant [Yang et al., 2003]. The development
of this interface is complex and is infl uenced by numerous factors, including
surface chemistry and surface topography of the foreign material [Albrektsson
et al., 1983; Kasemo et al., 1986; Schenk et al., 1998; Masuda et al., 1998; Larsson
et al., 2001]. For example, Oshida et al. treated NiTi by acid-pickling in
HF:HNO 3 :H 2 O (1 : 1 : 5 by volume) at room temperature for 30 seconds to control
the surface topology and selectively dissolve Ni, resulting in a Ti-enriched surface
layer [Oshida et al., 1992], demonstrating that surface topology can be relatively
easily controlled.
The role of surface roughness on the interaction of cells with titanium model
surfaces of well-defi ned topography was investigated using human bone-derived
cells (MG63 cells). The early phase of interactions was studied using a kinetic
morphological analysis of adhesion, spreading, and proliferation of the cells. SEM
and double immunofl uorescent labeling of vinculin and actin revealed that the
cells responded to nanoscale roughness with a higher cell thickness and a delayed
apparition of the focal contacts. A singular behavior was observed on nanoporous
oxide surfaces, where the cells were more spread and displayed longer and more
numerous fi lopods. On electrochemically microstructured surfaces, the MG63
cells were able to go inside, adhere, and proliferate in cavities of 30 or 100
μ
m in
diameter, whereas they did not recognize the 10
m diameter cavities. Cells
adopted a three-dimensional shape when attaching inside the 30
μ
μ
m diameter
cavities. It was concluded that nanotopography on surfaces with 30
m diameter
cavities had little effect on cell morphology compared to fl at surfaces with the
same nanostructure, but cell proliferation exhibited a marked synergistic effect
of microscale and nanoscale topography [Zinger et al., 2004].
It was pointed out that surface topography played an importance on cellular
reactions [Eriksson et al., 2001]. Surface plays a crucial role in biological interac-
tions for four reasons. First, the surface of a biomaterial is the only part in contact
with the bioenvironment. Second, the surface region of a biomaterial is almost
μ
Search WWH ::




Custom Search