Transcript Porosity Response of Layer-by- Layer Nanocapsules on the Basis of Ultraviolet Light

Porosity Response of Layer-byLayer Nanocapsules on the Basis
of Ultraviolet Light
David Huang
University of Texas at Austin
Department of Biomedical Engineering
Dr. Frank Ji, Ph.D.
Drug Delivery via Nanocapsules
• Nanocapsule
– shell of polymer
nanoparticles
– Held together by
electrostatic forces
• Drug kept inside until
released
Benefits of Nanocapsules
• Receptors can be added
without change to drug
structure
• Minimize drug degradation
• Increase drug bioavailability
• Dosage for drugs can be
decreased by 10,000 folds
Controlling Rate
• Looking for a method pulsatile release
• Controlling Rate of Release of the Drug
via light energy
– Energized Bonds causes Conformational
Change
Demonstration of Concept
• Would conformational change really cause a
noticeable difference in rate of release?
• Ultraviolet Light (355 nm) used especially just for
demonstration
• Drug replaced by Fluorescein dye to be detected
once released
• Polymer used:
Poly[1-[4-(3-carboxy-4hydroxyphenylazo)ben
zenesulfonamido]-1,2ethanediyl, sodium
salt] (PHES)
Plans to test Concept
• Create two samples of the nanocapsules
• Fill them with dye
• Place them in two environments
– Absence of light
– UV emitter
• Measure the rate of release of the dye
Creating and Filling Nanocapsules
Silica Particle
PHES
PEI
Fluorescein
Testing Phase
Fluorescent Intensity Released by
Nanocapsules over Time
Fluorescent Intensity
70
Nanocapsules under the
absence of light
Nanocapsules energized
by UV light
60
50
40
30
20
10
0
0
50
100
150
200
Time (min)
250
300
Fluorescent Intensity Released by Nanocapsules
Energized by UV Light
Fluorescent Intensity
70
60
Intensity after 5 min
Intensity after 10 min
Intensity after 15 min
50
Intensity after 20 min
40
30
20
10
0
400
450
500
550
-10
Wavelength (nm)
600
650
Fluorescent Intensity Released by
Nanocapsules in the Absence of Light
70
Intensity after 5 min
Intensity after 10 min
Intensity after 15 min
Intensity after 20 min
Fluorescent Intensity
60
50
Intensity after 25 min
40
30
20
10
0
400
-10
450
500
550
Wavelength (nm)
600
650
Increasing Fluorescent Intensity Released
by Nanocapsules over Time
90
y = 3.041x + 22.745
Fluorescent Intensity
80
70
60
50
y = 0.7972x + 33.23
40
30
In the Absence of Light
Energized by UV Light
20
10
0
0
5
10
15
Time (min)
20
25
Looking at the Rates
• Energized by UV
– y = 3.041x + 22.745
• In the absence of Light
– y = 0.7972x + 33.23
Problems?
• Decreasing Fluorescent Intensity?
– Maybe some unknown reaction
• One factor overlooked
– temperature
Conclusion
• Demonstration proved that this Pulsatile
method is possible in controlling the rate of
release by nanocapsules
• The energized nanocapsules released
substance within with a higher rate
The Next Step
• Cross-linking infrared induced
conformational change polymers to the
nanocapsules
• Filling nanocapsules with drugs
Questions?
References
•
•
•
•
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L P M Lloyd-Evans & BioBridge 2000-2005. http://www.biomateria.com/issue_5_book_review.htm
Costas Kaparissides, Sofia Alexandridou, Katerina Kotti and Sotira Chaitidou. “Recent Advances in Novel
Drug Delivery System.” AZojon Journal of Nanotechnology Online. March 2006.
Tatsiana Shutava, Malcolm Prouty, Dinesh Kommireddy, Yuri Lvov, “pH Responsible Decomposable Layer-byLayer Films and Capsules on the Basis of Tannic Acid,” Macromolecules, 38(7), Mar. 2005, 2850-2858.
Zonghuan Lu, Malcolm D. Prouty, Zhanhu Guo, Challa S. S. R. Kumar, Yuri M. Lvov, “Magnetic Switch of
Permeability for Polyelectrolyte Microcapsules Embedded with Co@Au Nanoparticles,” Langmuir, 21(5), Jan.
2005, 2042-2050.
http://www.innovations-report.de/html/berichte/biowissenschaften_chemie/bericht-38462.html
Acknowledgements
I would like thank Dr. Frank Ji, Ph.D., Dr. Steven Jones Ph.D. and Xing Yang for their guidance and
assistance. Great thanks also to the Louisiana Tech Institute of Micromanufacturing and
Department of Chemistry for their facilities and equipment. And to the National Science
Foundation for their Financial Support.