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Encapsulated silica colloidal particles using layer by-layer electrostatic self-assembly of polyelectrolytes and fluorescent dye Benjamin Holden Department of Biological Engineering, University of Arkansas ,. D. Patrick O’Neal, Ph. D. | Biomedical Engineering Department. - PowerPoint PPT Presentation
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LOUISIANA TECH UNIVERSITYCollege of Engineering and Science
Encapsulated silica colloidal particles using layer by-layer electrostatic self-assembly of polyelectrolytes and fluorescent dye
Benjamin Holden Department of Biological Engineering, University of Arkansas,
D. Patrick O’Neal, Ph. D. | Biomedical Engineering Department
LOUISIANA TECH UNIVERSITYCollege of Engineering and Science
• Nanoparticles for cancer therapy1. Small >150 nm2. Highly fluorescent3. Compatible with drug delivery
Benjamin Holden | Biological Engineering Department University of Arkansas
LOUISIANA TECH UNIVERSITYCollege of Engineering and Science
Flow of particles thru Leaky Vasculature of Tumors
TumorCells
BloodSupply
Normal flow of particles
LOUISIANA TECH UNIVERSITYCollege of Engineering and Science
Nanoparticles with Encapsulated TamoxifenNanoparticles with Encapsulated Tamoxifen
SEM Images: Tamoxifen nanoparticles of approximately (b) 122 and (c) 134 nm after 20 minute sonication in a polycation bath. Samples images are taken 48 hours after LbL process is complete.
Y. Lvov, in collaboration with V. Torchilin
Benjamin Holden | Biological Engineering Department University of Arkansas
LOUISIANA TECH UNIVERSITYCollege of Engineering and Science
Near-infrared window into tissueTissue Optical Window
http://www.ctl.com.pl/art/art4b.html 400 500 600 700 800 900 1000 1100
NIR-664
ICG
LOUISIANA TECH UNIVERSITYCollege of Engineering and Science
• RESEARCH OBJECTIVE – devolve a technique to coat nanoparticles using layer by layer with a fluorescent dye.– Methods
• Adding dye to polyelectrolyte• Layer by layer• Coating a slide• Coating nanoparticles
Benjamin Holden | Biological Engineering Department University of Arkansas
LOUISIANA TECH UNIVERSITYCollege of Engineering and Science
Problems with ICG
1. Aggregation 2. Solubility 3. Stability4. Photo-bleaching
Benefits of ICG
1. FDA approved2. Inside tissue optical window
Benjamin Holden | Biological Engineering Department University of Arkansas
LOUISIANA TECH UNIVERSITYCollege of Engineering and Science
Instability of ICG
0.15
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0.25
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0.35
0 50 100 150 200 250 300
Time (min)
Abs
In Dark
In light
Benjamin Holden | Biological Engineering Department University of Arkansas
LOUISIANA TECH UNIVERSITYCollege of Engineering and Science
+Benjamin Holden | Biological Engineering Department University of Arkansas
-0.5
0
0.5
1
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400 500 600 700 800 900 1000 1100
Wavelength (nm)
NIR-664_PDDANIR-664-PEINIR-664-PAH
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0.05
0.1
0.15
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0.25
0.3
0.35
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400 500 600 700 800 900 1000 1100
Wavelenght (nm)
ICG-P AH
ICG-P DDA
ICG-P E I
Addition of dye to polyelectrolyteAbsorption spectra of ICG-PDDA (blue line), ICG-PEI (red line), and ICG-PAH (black line) in
0.1 M sodium bicarbonate
Absorption spectra of NIR-664-PDDA (blue line), NIR-664--PEI (red line), and NIR-664-PAH (black line) in DI H2O
LOUISIANA TECH UNIVERSITYCollege of Engineering and Science
-0.01
0
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400 500 600 700 800 900 1000 1100
Wavelength (nm)
5 layers4 layers3 layers2 layers
Absorption spectra of glass slide with increasing intensity with increasing dye-polyion layers
Glass slide coated with ICG using layer by layer assembly
Benjamin Holden | Biological Engineering Department University of Arkansas
LOUISIANA TECH UNIVERSITYCollege of Engineering and Science
(a) (b) (c)
(f) (e) (d)
Benjamin Holden | Biological Engineering Department University of Arkansas
Layer by layer assembly on silica particles
LOUISIANA TECH UNIVERSITYCollege of Engineering and Science
0
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675 685 695 705 715 725 735 745
Wavelen ght ( n m)
NI R_664 Coat 2
NI R-664 Coat 1
Surface Charge
Baseline Layers
≈DiameterBaseline
Layer ≈DiameterH2O sol
- Silica 124 nm Colloidal silica
124 nm
+ PDDA 158 nm PDDA 168 nm
- PSS 160 nm PSS 158 nm
+ PDDA 186 nm PDDA-NIR-664
204 nm
- PSS 191 nm PSS 209 nm
+ PDDA 205 nm PDDA-NIR-664
645 nm
Layer by in DI H2O and NaCl, particle size and surface charge of colloidal silica particles.
Silica particle layer thickness
Silica fluorescence
Benjamin Holden | Biological Engineering Department University of Arkansas
LOUISIANA TECH UNIVERSITYCollege of Engineering and Science
Discussion
• What are some possible causes for the aggregation of particles?
• Possible solutions for aggregation.
Benjamin Holden | Biological Engineering Department University of Arkansas
LOUISIANA TECH UNIVERSITYCollege of Engineering and Science
Conclusion
• Objective accomplishments • What’s next?
Benjamin Holden | Biological Engineering Department University of Arkansas
LOUISIANA TECH UNIVERSITYCollege of Engineering and Science
Questions ?
Benjamin Holden | Biological Engineering Department University of Arkansas
Acknowledgments
I thank Dr. P. O’Neal for his guidance and many helpful discussions. I would also like to thank Saleh Ramazani and Greg for there help in the day to day operation of my project. Special thanks to Dr Jones, Dr Lvov, and the National Science foundation. I am grateful to the staff of the IFM and BME buildings for the use of there facilities
and equipment