Download - PAC presentation Anca V2
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Stability of polymersomes containing 111In using Perturbed Angular Correlation spectroscopy
Anca Tacu
Supervisor: Peter Bode
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1. Introduction
2. Data Interpretation
3. Results & Discussion
4. Conclusion
5. Future Work
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Cancer
Tumour tissueIncreased permeability of blood vessels
Dysfunctional lymphatic drainage
Accumulation nanocarriers
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Loading efficiencylpmoltC
In/5.0)( 0111
lpmoltCCd
/86.1)( 0111
Efficiency of loading dependent on:• age of stock solution • type of buffer
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PACMeasures correlation between the directions of emission of 2 consecutive γ-rays
Directional probability of emission dependent on:•orientation of the nuclear spin axis •surrounding electrical field
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Stop,θ
Clock,t1
2
θ
Start
Differentiate between different surrounding media of the radionuclide studied
PAC
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PAC
180 9022
22 22 180 90
12
N NG
A Q N N
180 9022
22 22 180 90
12
N NG
A Q N N
22 0.5G
Highly perturbed 0 ≤ G22 ≤ 1 No perturbation
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PAC
Parameters:• Relaxation time• The skn(η) coefficients• The precession frequencies: ωkn(η)
),cos()(3
0
tsetG knn
knt
kkk
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Results & Discussion3 sets of measurements:
• 111InCl3 crystalized and in solution at pH 2
• 111In-DTPA and 111In-Tropolone complexes
• 111In loaded polymersomes
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Results & DiscussionSpecifications sample
Activity sample
Time since Calibration
Experimental Reference
Crystalized InCl3 300 kBq 10 d -0.15 0.14-0.02
Liquid 111InCl3 300 kBq 11 d 1.48 0.98Liquid 111InCl3 (liquid nitrogen)
0.08
22G
180 9022
22 22 180 90
12
N NGA Q N N
0 ≤ G22 ≤ 1A22 = -0.0870Q22 = 0.8066N180-N90<0
22G
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Results & DiscussionSpecifications sample Activity
sampleTime since calibration
111In-DTPA in HEPES 130 kBq 17 d 0.31111In-DTPA in HEPES (liquid nitrogen) -0.57 111In-DTPA in PBS 0.57 111In-DTPA in PBS (liquid nitrogen) -1.93111In-Tropolone in HEPES 420 kBq 15 d 0.04 111In-Tropolone in PBS 0.23 111In-Tropolone in PBS (liquid nitrogen) -1.23
22G
Issue with the detectorOR
Correlation times of molecules too small to be detected by the PAC
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Stability vs. Instability180 90
2222 22 180 90
12
N NGA Q N N
A22 = -0.0870Q22 = 0.8066
N180-N90<0
Assumption 180o detector stable: N180=90 000Case 1:
N90=60 000N90=100 000
Case 2:
22 0.67G 22 2.03G
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Results & DiscussionSpecifications sample Activity
sampleTime since calibration
200 nm polymersomes in PBS
1st day 170 kBq 1 d 0.39 2nd day 130 kBq 2 d 0.26
200 nm polymersomes in HEPES
1st day 140 kBq 9 d 0.042nd day 110 kBq 10 d 0.17
400 nm polymersomes in HEPES
2nd day 140 kBq 10 d 0.12
800 nm polymersomes in HEPES
2nd day 170 kBq 10 d -0.05
22G
Size of polymersome seems not to have any influencePerturbation in HEPES polymersome seems to be higher than in PBS onesDoes the age of stock solution matter?
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Conclusion• PAC has potential
• The system seems to have technical problems
• Winfit was not a reliable software
• No final conclusions could be drawn- more
measurements should be made
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Future work1. Investigate:
• the influence of In3+
• the effect of Cd2+
• life-time of polymersomes upon systemic administration (in vivo & in vitro)
2. Was it just a problem with the detectors?
3. Purchase/ Implement a program for the data fitting