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)ben zenesulfonamido]-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 HF Silica Particle PEI PHES Fluorescein

Testing Phase

Fluorescent Intensity Released by Nanocapsules Energized by UV Light

Fluorescent Intensity Released by Nanocapsules in the Absence of Light

Increasing Fluorescent Intensity Released by Nanocapsules over Time

Looking at the Rates Energized by UV –y = 3.041x In the absence of Light –y = x

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 Costas Kaparissides, Sofia Alexandridou, Katerina Kotti and Sotira Chaitidou. “Recent Advances in Novel Drug Delivery System.” AZojon Journal of Nanotechnology Online. March 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, Zonghuan Lu, Malcolm D. Prouty, Zhanhu Guo, Challa S. S. R. Kumar, Yuri M. Lvov, “Magnetic Switch of Permeability for Polyelectrolyte Microcapsules Embedded with Nanoparticles,” Langmuir, 21(5), Jan. 2005, 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.