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Nanoparticle Interactions with Biomolecules: Implications for Disposition
Nanomaterials: Environmental Risks and Benefits and Emerging Consumer Products
NATO-OTAN Advanced Research Workshop
April 27-30, 2008
Alison ElderDepartment of Environmental Medicine,
University of Rochester
Exposures to Nanomaterials: Most Likely Routes
From: Borm et al., 2006
Respiratory tract
GI tract
Skin
Gastrointestinal Tract
• Data suggests that persorption of particles can occur.– Persorption of micron-sized “insoluble” PVC particles
(Volkheimer, 1975).– About 0.0001% Pu dioxide GI tract absorption in humans
(Stather et al., 1979).– No absorption of orally-administered poorly-soluble 15 nm
192Ir particles from GI tract (Kreyling et al., 2002).• Tissue distribution of colloidal Au nanoparticles is
size-dependent following exposures in drinking water for 7 days (Hillyer and Albrecht, 2001).
Does particle density play a role?
Skin Architecture
Basementmembrane
From: Bouwstra et al., 2006
Key Considerations for Studies of Nanomaterials Interactions with Skin
• Surface pH of ~5.0• Lipid lamellae of stratum corneum
Main question: Can nanoparticles breach the stratum corneum and under what conditions?
Tissue Cadmium Content 24 hrs following IntratrachealMicrospray Exposure of Surface-Modified QDots
(Rats, 5 μg Cd sprayed in 3x50 μl)
0.01
0.1
1
10
100
1000
10000
ControlPEGPEG-amine
Note: No Cd was detectable in cerebrum, cerebellum, or olfactory bulbs<L
OQ
<LO
Q
<LO
Q
<LO
Q
<LO
Q
<LOQ <LOQ<LOQ
Carboxyl
Lung HeartBoneMarrow
LiverSpleen KidneyLymphnodes
LavageSup.
LavageCells
Trachea
* *****
**
*
**
p<0.05
**
Cd
Con
tent
, Tot
al n
g
*, vs. control, p<0.05.
Tissue Cadmium Content 24 hrs following IntravenousExposure to Surface-Modified QDots
(Rats, 1.7 μg Cd injected in 200 μl)
0.01
0.1
1
10
100
1000
10000
Lung HeartBoneMarrow
LiverSpleen KidneyLymphnodes
LavageSup.
LavageCells
ControlPEGPEG-amine
<LO
Q
<LO
Q
<LO
Q
<LO
Q
<LO
Q
<LO
Q<LOQ
Blood
<LOQ
*
**#
*
*
*
#
#
#
# #
**
#
**
Carboxyl
Cd
Con
tent
, Tot
al n
g
**
#
*, vs. control, p<0.05;#, vs. all other groups, p<0.05.
Tissue Cd Levels 7 Days after Exposure
Tissue Cadmium Content following IntratrachealMicrospray of Surface-Modified QDots
7 days after Instillation (Rats, 10 μg Cd 3x 150 μl)
Lung Pellet Super Trachea LN-Lung LN-Axil. LN-Illiac Kidney Spleen Liver BM0.01
0.1
1
10
100
Control
100
1000
10000Note: No Cd was detectable in BM, Heart, Blood, Brain tissue
PEG 7DayPEG-amine 7DayCarboxyl 7Day
Cd
Con
tent
, Tot
al n
g
Tissue Cadmium Content following IntraveniousInjection of Surface-Modified QDots
7 days after Injection (Rats, 5 μg Cd 200 μl)
Lung Pellet Super Trachea LN-Lung LN-Axil. LN-Illiac Kidney Spleen Liver BM Heart Blood CSF0.01
0.1
1
10
100
Control
100
1000
10000 Note: No Cd was detectable in cerebrum, cerebellum, or olfactory bulbs
PEG 7DayPEG-amine 7DayCarboxyl 7Day
Cd
Con
tent
, Tot
al n
g
Intratracheal Microspray Intravenous Injection
Liver Cd Levels: Comparison of Exposure Route (and Surface Coating)
0
1000
2000
3000
4000
5000
6000
PEGPEG-amineCarboxyl
Liver Cd Levels following Intravenous Injection of Quantum Dotswith Different Surface Coatings
0 1
Days7
ng C
d
0
50
100
150
Liver Cd Levels following Intratracheal Microspray Delivery of Quantum Dotswith Different Surface Coatings
PEGPEG-amineCarboxyl
1000
1250
1500
1750
2000
ng C
d
0 1
Days7
Intratracheal Intravenous
Tissue Au Content 24 hrs following Intratracheal Microspray Exposure to Colloidal Au Nanoparticles with Different Surface Coatings
0.00
0.05
0.10
0.15
Citrate
PEG 5kSerum albumin
PEG 20k
LALN Bone Marrow BloodSpleen KidneyHeart
0.2
0.3
0.4
0.5
% o
f Adm
inis
tere
d D
ose
(+SD
)
Tissue Au Content 24 hrs following Intravenous Exposure to Colloidal Au Nanoparticles with Different Surface Coatings
0
1
2
3
4
5
Citrate
PEG 5kSerum albumin
PEG 20k
LALN Bone Marrow BloodSpleen KidneyHeart
20
40
60
80
100
120
140
% o
f Adm
inis
tere
d D
ose
(+SD
)
Translocation of Nanogold to the Brain
0.000
0.001
0.002
0.003
0.004
0.005
0.006
Time post exposure
5nm Gold, surface modified:Au in brain after ITM Exposure
1-hour 24-hour
Citrate
PEG 5kSerum albumin
PEG 20k
% o
f Adm
inis
tere
d D
ose
(+SD
)
0.00
0.03
0.06
0.09
0.12
0.15
Time post exposure
5nm Gold, surface modified:Au in brain after IV Exposure
1-hour 24-hour
Citrate
PEG 5kSerum albumin
PEG 20k
% o
f Adm
inis
tere
d D
ose
(+SD
)
Key Cross-Cutting Themes
• Nanoparticle physicochemical characteristics• Properties of portal of entry• Integrity of barrier• Responses caused by NP-cell interactions (e.g.
inflammation) are likely to affect biodistribution
AcknowledgementsAmber Rinderknecht
Nancy CorsonBob GeleinPamela Wade-Mercer
Günter OberdörsterJacob Finkelstein
Grant Support:EPA, NIH/NCIDoD, NSF
Questions?
Summary of Results1. Nanoparticles delivered via the lower respiratory
tract are translocated to extrapulmonary tissues• Dependent on particle physicochemical
characteristics.2. Nanoparticles can be retained in small amounts
by the brain following a single exposure• Dependent on particle physicochemical
characteristics and portal of entry.
Considerations Regarding Nanomaterials Absorption through Skin
• Penetration via hair follicles• Health or condition of skin
– UV radiation, tape stripping facilitate particle access to hair follicles (Sincai et al., 2007; Vogt et al., 2006).
– No penetration without flexion (Tinkle et al., 2003).• Nanoparticle size
– Positively-charged polystyrene beads (20-40 nm) found in follicles at level of epidermis, dermis – particles over 200 nm did not penetrate (Alvarez-Román et al., 2004; Vogt et al., 2007).
– Small percentage of dextran beads penetrate to level of dermis – size cut-off between 1 and 2 μm (Tinkle et al., 2003).
Study Design: Nanoparticle Characteristics
• Characteristics of the QDots:– CdSe/ZnS core-shell particles coated with polymer, ~5
nm core-shell diameter (Invitrogen) – 565 nm emitters– PEG, PEG-amine, or carboxyl conjugated surfaces
• Characteristics of colloidal Au particles:– 5 nm primary particle size (Ted Pella, Inc.)– Coated with albumin, 5 kDa PEG, or 20 kDa PEG
CdSe-ZnS Quantum Dots in 0.9% Saline
PEGylated23 nm
Carboxylated13 nm
PEGamine17 nm
Hydrodynamic Radii of Colloidal Gold Nanoparticles (5 nm)
0
5
10
15
20
25
0.1 1 10 100 1000 10000
Vol
ume
(%)
Size (d.nm)
Citrated AuRSA-AuPEG (5K)-AuPEG (20K)-Au
8 nm19 nm28 nm47 nm
Peak MeanSurface Coating
from: Dr. A. Rinderknecht
Study Design: Nanoparticle Exposures
• Exposures to QDots (dose expressed as Cd content):– Intratracheal microspray (5 μg Cd/150 μl saline)– Intravenous injection (1.7 μg Cd/200 μl saline)
• Exposures to colloidal Au:– Intratracheal microspray (50 μg/150 μl saline)– Intravenous injection (15 μg/200 μl saline)