Biomedical Engineering Reference
In-Depth Information
h e mouse monoclonal Ab to anti-human Mb were deposited on the
surface of PS samples by spontaneous sorption. In this case they were
immersed into the Ab solution prepared on 20 mM PBS, pH 7.3. As ade-
quate time for further experiments it was chosen period in 60 min since
the time in 15 and 30 min of Ab immobilization are rather short to have on
the surface such a quantity of Ab which is sui cient for the sensitive detec-
tion of Mb. h en PS surface was washed with PBS, pH 7.3. h ree samples
of human serum were used: undiluted, diluted to 1:10 and to 1:100. Mb
concentration was determinhed by the ELISA-method too. In last case
monoclonal mouse Ab to two dif erent Ag sites of Mb were used. One type
of the Ab was immobilized on the surface of plates, while other ones, con-
jugated with HRP, served to detect Mb.
13.2.4.2
Study of the Main Characteristics of PS PhL and
Quantitative Mb Determination [9, 10]
Earlier, it was demonstrated [10] that at the contact of PS with distilled
water, or 10 mM TB, pH 7.3, or TBS, or solutions of BSA, or rabbit IgG,
or sheep anti-rabbit IgG prepared in above mentioned buf ers, its typi-
cal PhL spectra remained almost immutable during no less than 2-2.5 h.
At the same time at er previous deposition of Ab or Ag on the PS and
their consecutive contact with the solution of corresponding Ag or Ab a
great reduction of the PhL intensity was observed. According to the exist-
ing ideas [11-17] the nature of the visible PhL of PS can be explained by
a process of dehydrogenization of the PS surface, which takes place at er
a specii c immune complex formation. Hydrogen is released from silicon
bonds and subsequently captures by the immune complex. Torn Si bonds
are known to intensify non-radioactive channel of recombination, which
leads to the decrease of the PhL intensity. h e overall view of PS by atom
force microscopy in dif erent situation is shown in Figure 13.5.
In the following experiments an adequate concentration of Ab to be
deposited on the PS surface was studied. PS samples were immersed into
the Ab solutions of dif erent concentrations for 60 min. h en PS samples
with Ab on the surface were immersed into 20 mM Na-PBS (pH 7.3) with
Mb in the concentration equal to 0.1 μg/ml. It was shown that at er the i rst
10 min of the experiments in all samples the decrease of the PhL inten-
sity already took place. In the case of the PS samples on which Ab were
deposited in the solutions of 20 μg/ml, through 30-35 min at er the begin-
ning of the measurements the decrease in the PhL intensity was up to 80%
from the initial level. In 20-30 min the magnitude of the PhL intensity
was 50% from the initial level. During 30-35 min the PhL intensity of PS
