Biomedical Engineering Reference
In-Depth Information
10.5.1 Single cell
We include in this section comparison with optical tweezers experiments and with
microfluidics to assess the fidelity of the RBC models to reproduce the mechanics
and dynamics of Pf-RBCs.
10.5.1.1 Mechanics
In malaria disease, progression through the parasite development stages leads to a
considerable stiffening of Pf-RBCs compared to healthy ones [9, 12]. Furthermore,
in the schizont stage the RBC shape becomes near-spherical whereas in the preced-
ing stages RBCs maintain their biconcavity. Fig. 10.18 shows simulation results for
Pf-RBCs at different stages of parasite development. The simulation results were ob-
tained with the MS-RBC model using 500 points. Table 10.1 presents the shear mod-
uli of healthy and Pf-RBCs at different stages; these values are consistent with the
experiments of [9, 12]. The bending rigidity for all cases is set to 2
10
−
19
J
, which
is the value of bending rigidity for healthy RBCs, as the membrane bending stiffness
for different stages is not known. The curve for the schizont stage marked as “near-
spherical” corresponds to stretching an ellipsoidal shape with axes
a
x
=
.
4
×
a
y
=
1
.
2
a
z
.
Here, the membrane shear modulus of 40
μ
N/m matches the stress-strain response
Healthy
Trophozoite
Schizont
experiment
simulation
schizont, near-spherical
20
D
A
18
16
14
12
10
8
6
4
D
T
2
0
0
50
100
150
200
force (pN)
Fig. 10.18.
Stretching response of Pf-RBCs using the MS-RBC for different stages compared with
the experiments [9].
D
A
and
D
T
refer to the axial and transverse diameters (from [51])
23
◦
C. The “*” denotes a “near-
μ
N
/
m
at
T
=
Table 10.1.
Shear moduli of healthy and Pf-RBCs in
spherical” RBC at the schizont stage
Healthy
Ring
Trophozoite
Schizont
60 & 40
∗
6
.
3
14
.
5
29
