Biomedical Engineering Reference
In-Depth Information
were completed within 45 min from the time each bone sample was taken
out of the PBS solution. The indentation diagonals were measured with opti-
cal microscopy. Three samples from the same maceration were selected for
repeat tests. ANOVA at a 5% significance level was applied for the statistical
analysis of hardness values.
9.2.5 Results for the Samples after Removal of Soft Tissues
Yin et al. [5] found that all the bone samples showed appreciable change after
the 5-day maceration in each solution at room temperature. All the marrows
were easily removed using a wooden rod and a brush. The soft tissues of
the bone samples macerated in solution A (water) were difficult to remove.
Cleaning was conducted carefully by scratching the soft tissues using a knife.
The bone samples in solution B (trypsin) become completely disarticulated
and the soft tissues could be easily separated and cleaned with a scouring
pad without any damage to bone surfaces. In comparison of the dissolving
abilities between the two laundry detergents, Surf (solution C) and Biozet
(solution D), the bone samples macerated in Surf still showed a large amount
of soft tissue adhering on the bone surfaces, whereas the samples treated
with Biozet were almost free of soft tissue, and remnants of soft tissue could
be easily removed.
A noxious chemical odor was associated with the samples macerated in
water and trypsin. In particular, the bone samples treated in trypsin were
extremely malodorous at room temperature, causing strong offense to
people. The smells of the bone samples treated with Biozet and Surf laundry
powders were much more acceptable. In particular, the bone samples treated
with Biozet produced a pleasant odor.
9.2.6 Change of Microstructure with Cleaning Procedure
The SEM micrographs demonstrating the microstructures of the bone sam-
ples prepared in each solution are shown in Figure 9.1 [5]. There are no vis-
ible differences among these four microstructures. All microstructures show
the typical osteonal structure of compact (cortical) bone. Figure 9.2 shows
typical osteons, which were formed rather like plywood from sheets of alter-
nating lamellae that could be laid flat, or curved around in circles to pro-
tect blood vessels. The osteons took the form of planar ellipses. One had a
major axis approximately 100 μm in length and a minor axis approximately
50 μm in length. The pores with diameters larger than 10 μm were formed
from Haversian canals or blood vessels. Smaller pores were formed from
lymphatic vessels and lacuna canaliculi.
Figure 9.3(a) demonstrates one example of identification, analysis, and
calculation of porosity in a region of interest. Figure 9.3(b) shows the pore
size distribution in the region, indicating that 4% of pores have a diameter of
10-20 μm and 96% of pores have a diameter smaller than 10 μm. The porosities
