2012.8.14 1 DNA-Conjugated Gold Nanoparticles as Ultrasound- Responsive Drug Delivery Systems Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University Hsinchu, Taiwan. Shih-Tsung Kang, Yun-Ling Luo, Yu-Fen Huang, Chih-Kuang Yeh
22
Embed
2012.8.14 1 Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University Hsinchu, Taiwan.
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
1
2012.8.14
DNA-Conjugated Gold Nanoparticles as
Ultrasound-Responsive Drug Delivery
Systems
Department of Biomedical Engineering and Environmental Sciences,
No cytotoxicity was observed for Dox:ds(control)-Au NPs (without specific binding affinity)
ds(sgc8c)-Au NPs (without Dox payload)
**: p < 0.0115%
10
Pure
Cells
Dox:d
s(sg
c8c)
PDPH-D
ox-sgc
8c-A
u N
Ps
Dox:d
s(sg
c8c)
-Au
NPs
05
1015202530354045
Pre-HIFUPost-HIFU
MF
I (a
.u.)
Comparisons of Different Cases
Dox release was only achieved when both Dox-DNA complexes and Au NPs were present.
Varying HIFU Parameters11
Release of Dox can be achieved by ultrasound excitation at low acoustic pressures and duty cycles
0 2 3 4 515
20
25
30
35
40
45
50
55
Pressure (MPa)
MF
I (a
.u.)
0 0.5 1 2 3 4 5 1015
20
25
30
35
40
45
Duty Cycle (%)
MF
I (a
.u.)
Pressure: 4 MPa.Duty cycle: 10%
Sonication Time (s)
Tem
pera
ture
(˚
C)
ΔM
FI
(a.u
.)Δ
MFI
(a.u
.)
Normal Degassed
**
Au
Possible mechanisms
• Thermal effects?• Mechanical effects?
Microcavitation
Focal intensity: ~140 W/cm2
13
Pure Cells ds(sgc8c)-Au NP Cell with H2O20
5
10
15
20
25
30
Pre-HIFUPost-HIFUM
FI
(a. u
.)
Intracellular Reactive Oxygen Species
Cells were treated with DCFH-DA before HIFU treatments
ROS production was observed in Cells with ds(sgc8c)-Au NPs after HIFU
treatments.
s
14
Summary• Au NPs conjugated with Dox-DNA complexes have shown to
be ultrasound-responsive drug delivery systems. The drug release mechanism was found to relate to microcavitation.
• The presence of Au NPs might provide nucleation sites for facilitating gas nuclei on the surface of Au NPs to grow into cavitation bubbles under HIFU excitation.
• Further investigation is required to clarify which phenomena during microcavitation responsible for the Dox release.
• ROS scavenger treatment.• DNA integrity evaluation.• Different HIFU parameters.• Different types of nanoparticles.
Thanks for your attention.
15
16
Enhanced Dox LeakageAfter HIFU Treatment
0 2 4 6 8 10 120
20
40
60
80
100
120
CellCell-ultrasound56 nm56 nm-ultrasound
Time (hr)
Gm
(a.
u.)
2.6-fold increase
17
Varying Concentration of Au and Gas Content (ROS measurement)
ROS-ds-sg
c8c-Au N
P (0.0
625x)
ROS-ds-sg
c8c-Au N
P (0.1
25x)
ROS-ds-sg
c8c-Au N
P (0.2
5x)
ROS-ds-sg
c8c-Au N
P (0.5
x)
ROS-ds-sg
c8c-Au N
P v.s. d
s-sg
c8c
0
5
10
15
20
25
30
35
(56 nm Au NP )
ultrasound w/o
ultrasound w
Gm
(a. u
.)
18
Cellular uptake of ds(sgc8c)-Au NPs determined by atomic absorption spectra.
19
TEM image of 13-nm Au NPs
20 μm
20
MTT Assay
a) nontreated cells, and cells incubated with
b) Doxc) Dox:ds(sgc8c), d) Dox:ds(sgc8c)-Au NPse) Dox:ds(control)-Au
•Pyrolysis in bubble interior.▫Dissociation due to high temperature.
•Hydroxylation at bubble interface.▫Reaction with Reactive Oxygen Species.
•Super-critical water at bubble interface.
I. Hua, R. H. Hoechemer, and M. R. Hoffmann, “Sonolytic Hydrolysis of p-Nitrophenyl Acetate: The Role of Supercritical Water,” The Journal of Physical Chemistry, vol. 99, no. 8, pp. 2335-2342, Feb. 1995.