Figures & data
Figure 1 A graphical representation of NiTi material properties. The thermal shape memory effect (A) involves the transformation from the austensitic to martensitic phase and vice versa. Permanent deformation is achieved in the martensite phase and below the As transformation temperature. The strain-temperature relation (B) suggests that strain can be achieved as temperature is decreased and this strain is retained if the temperature is kept below As.
Figure 2 SEM images of NiTi compacts with two different surface roughness properties. Compared to the coarse grain NiTi samples, the fine grain NiTi samples had a greater percentage of sub-micron to nanometer size particles and a greater percentage of interparticulate voids providing for increased sub-micron to nanometer roughness.
Figure 3 Fluorescent microscope images of endothelial cell adhesion results showed greater endothelial cell density on the fine grain NiTi substrates as compared to the coarse grain NiTi and c.p. Ti after 5 hours. Arrows point to endothelial cells.
Figure 4 Endothelial cell adhesion increased on fine grain NiTi substrates with greater submicron to nanometer surface features after 5 hours, *p < 0.01 compared to all other substrates. The difference in endothelial cell adhesion between coarse grain NiTi, c.p. Ti, and the control was not significant. Data = mean +/− S.E.; N = 3. Control = tissue culture polystyrene.
Figure 5 Endothelial cell density increased on fine grain NiTi substrates with greater sub-micron to nanometer surface features after 1 day. The difference in the number of endothelial cells between fine and coarse grain NiTi substrates was significant, *p < 0.01. However, there was no significant difference in endothelial cell density between fine grain NiTi and c.p. Ti. Data = mean +/− S.E.; N = 3. Control = tissue culture polystyrene.
Figure 6 Fluorescent microscope images of endothelial cells after (A) 1 day (Bars = 100 μm) and (B) 5 days (Bars = 50 μm) on fine and coarse grain NiTi and c.p. Ti substrates. Endothelial cells were more confluent on fine grain NiTi after 5 days compared to coarse grain NiTi.
