D. Patrick O’Neal, Ph. D. | Biomedical Engineering Department

1. 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

2. Nanoparticles for cancer therapy • Small >150 nm • Highly fluorescent • Compatible with drug delivery Benjamin Holden | Biological Engineering Department University of Arkansas

3. Normal flow of particles Flow of particles thru Leaky Vasculature of Tumors Blood Supply Tumor Cells

4. Nanoparticles with Encapsulated Tamoxifen Y. Lvov, in collaboration with V. Torchilin 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. Benjamin Holden | Biological Engineering Department University of Arkansas

5. Near-infrared window into tissue Tissue Optical Window http://www.ctl.com.pl/art/art4b.html

6. 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

7. Problems with ICG • Aggregation • Solubility • Stability • Photo-bleaching Benefits of ICG • FDA approved • Inside tissue optical window Benjamin Holden | Biological Engineering Department University of Arkansas

8. Instability of ICG Benjamin Holden | Biological Engineering Department University of Arkansas

9. + Addition of dye to polyelectrolyte Absorption 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 Benjamin Holden | Biological Engineering Department University of Arkansas

10. Glass slide coated with ICG using layer by layer assembly Absorption spectra of glass slide with increasing intensity with increasing dye-polyion layers Benjamin Holden | Biological Engineering Department University of Arkansas

11. (a) (b) (c) (f) (e) (d) Layer by layer assembly on silica particles Benjamin Holden | Biological Engineering Department University of Arkansas

12. Silica particle layer thickness Silica fluorescence Benjamin Holden | Biological Engineering Department University of Arkansas

13. Discussion • What are some possible causes for the aggregation of particles? • Possible solutions for aggregation. Benjamin Holden | Biological Engineering Department University of Arkansas

14. Conclusion • Objective accomplishments • What’s next? Benjamin Holden | Biological Engineering Department University of Arkansas

15. Questions ? 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 Benjamin Holden | Biological Engineering Department University of Arkansas