porosity response of layer-by- layer nanocapsules on the basis of ultraviolet light david huang...
TRANSCRIPT
Porosity Response of Layer-by-Layer 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-4-hydroxyphenylazo)benz
enesulfonamido]-1,2-ethanediyl, 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
PEIPHES
Fluorescein
Testing Phase
Fluorescent Intensity Released by Nanocapsules over Time
0
10
20
30
40
50
60
70
0 50 100 150 200 250 300Time (min)
Flu
ore
sc
en
t In
ten
sit
y
Nanocapsules under theabsence of light
Nanocapsules energizedby UV light
Fluorescent Intensity Released by Nanocapsules Energized by UV Light
-10
0
10
20
30
40
50
60
70
400 450 500 550 600 650
Wavelength (nm)
Flu
ore
sc
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t In
ten
sit
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Intensity after 5 min
Intensity after 10 min
Intensity after 15 min
Intensity after 20 min
Fluorescent Intensity Released by Nanocapsules in the Absence of Light
-10
0
10
20
30
40
50
60
70
400 450 500 550 600 650
Wavelength (nm)
Flu
ore
sc
en
t In
ten
sit
y
Intensity after 5 min
Intensity after 10 min
Intensity after 15 min
Intensity after 20 min
Intensity after 25 min
Increasing Fluorescent Intensity Released by Nanocapsules over Time
y = 3.041x + 22.745
y = 0.7972x + 33.23
0
10
20
30
40
50
60
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80
90
0 5 10 15 20 25
Time (min)
Flu
ore
sc
en
t In
ten
sit
y
In the Absence of Light
Energized by UV Light
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• 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-by-
Layer 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
AcknowledgementsI 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.