Biomedical Engineering Reference
In-Depth Information
on the antibody concentration. These fi ndings could open a new alternative for the prevention of
angiogenesis, demonstrating the feasibility of using microencapsulated cells as a control drug-deliv-
ery system through an electrohydrodynamic processing technique.
11.2.8.5
Aerosolization of Biomaterials
Electrospraying has recently been explored for aerosolizing biorelated materials. The technique is
applied as a processing route for atomizing biological substances on a micrometer to nanometer
size. For example, the aerosol drug delivery offers a route for inhaling biomedicines as a therapeutic
treatment for diseases [105-107]. Moreover electrohydrodynamic process is a soft way to aerosolize
cell suspension to generate and deposit fi ne droplets containing living cells.
11. 2. 8 . 5 .1
DNA and Protein Biomolecule
Pareta et al. employed electrospraying to aerosolize BSA protein [108]. The solution for electro-
spraying was prepared by dissolving BSA in a mixture of 10 vol.% ethanol in deionized water with
a concentration of 5, 20, and 50 mg/mL. The solutions were fi ltered using a CA membrane to get rid
of any undissolved BSA. The apparatus used for aerosolizing BSA protein consisted of a syringe, a
syringe pump, a stainless steel nozzle, and a power supply. The spraying distance between the noz-
zle and the ground electrode was 10 mm. A high-speed camera was used to observe the jet modes
and capture the spraying images. Two BSA solutions were electrosprayed at a voltage of 6.5 kV and
a fl ow rate of 8
×
10
−11
m
3
/s for a concentration of 5 mg/mL, and a voltage of 6.5 kV and a fl ow
rate of 4
10
−11
m
3
/s for 20 mg/mL. The electrosprayed droplets of the BSA were collected just
below the ring ground electrode on a carbon-coated aluminum stub for a characterization by SEM.
The SEM image in Figure 11.49 shows that the size of the electrosprayed BSA relics were in the
range of 10-20 μm, and the aggregated relics contained clusters of small protein. The size of the
small BSA protein was a few micrometers. The experimental results revealed that a stable cone-jet
electrospraying mode for aerosolizing BSA protein could be achieved at the processing parameters:
electrospraying voltage
×
10
−10
m
3
/s for a concentration of 5 mg/mL.
The study demonstrated that electrospraying is a viable method for aerosolizing and encapsulating
proteins in biomedicines.
Davies et al. applied electrospraying technique to aerosolize plasmid DNA [109]. It was the fi rst
experiment to investigate the feasibility of electrospraying for the aerosol delivery of naked DNA
in vivo
, because the naked plasmid DNA (pDNA), a potential gene transfer agent for lung gene
therapies, cannot be aerosolized without a degradation using the conventional nebulization devices.
Unlike the conventional nebulizers that continually recycle aerosol, the electrosprayed pDNA was
<
6.5 kV and fl ow rate
<
2
×
10
µ
m
FIGURE 11.49
SEM image of BSA particles aerosolized by electrospraying. (Reprinted from Pareta, R.
et al.,
J. Mater. Sci. Mater. Med.
, 16, 919, 2005. © Springer Science and Business Media. With permission.)
