L OUISIANA T ECH U NIVERSITY College 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

L OUISIANA T ECH U NIVERSITY College of Engineering and Science Nanoparticles for cancer therapy 1.Small >150 nm 2.Highly fluorescent 3.Compatible with drug delivery Benjamin Holden | Biological Engineering Department University of Arkansas

L OUISIANA T ECH U NIVERSITY College of Engineering and Science Flow of particles thru Leaky Vasculature of Tumors Tumor Cells Blood Supply Normal flow of particles

L OUISIANA T ECH U NIVERSITY College of Engineering and Science Nanoparticles 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

L OUISIANA T ECH U NIVERSITY College of Engineering and Science Near-infrared window into tissue Tissue Optical Window

L OUISIANA T ECH U NIVERSITY College 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

L OUISIANA T ECH U NIVERSITY College of Engineering and Science Problems with ICG 1.Aggregation 2.Solubility 3.Stability 4.Photo-bleaching Benefits of ICG 1.FDA approved 2.Inside tissue optical window Benjamin Holden | Biological Engineering Department University of Arkansas

L OUISIANA T ECH U NIVERSITY College of Engineering and Science Instability of ICG Benjamin Holden | Biological Engineering Department University of Arkansas

L OUISIANA T ECH U NIVERSITY College of Engineering and Science + Benjamin Holden | Biological Engineering Department University of Arkansas 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

L OUISIANA T ECH U NIVERSITY College of Engineering and Science 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

L OUISIANA T ECH U NIVERSITY College 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

L OUISIANA T ECH U NIVERSITY College of Engineering and Science Surface Charge Baseline Layers ≈Diameter Baseline Layer≈Diameter H 2 O sol -Silica124 nmColloidal silica 124 nm +PDDA158 nmPDDA168 nm -PSS160 nmPSS158 nm +PDDA186 nmPDDA- NIR nm -PSS191 nmPSS209 nm +PDDA205 nmPDDA- NIR nm Layer by in DI H 2 O 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

L OUISIANA T ECH U NIVERSITY College 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

L OUISIANA T ECH U NIVERSITY College of Engineering and Science Conclusion Objective accomplishments What’s next? Benjamin Holden | Biological Engineering Department University of Arkansas

L OUISIANA T ECH U NIVERSITY College 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