Gate Control of Mesoporous Silica Nanoparticle with a-Synuclein Coated Gold Nanoparticles and Its Application to Control of Cancer Metastasis

학위논문 (석사)-- 서울대학교 대학원 : 화학생물공학부, 2016. 2. 백승렬.Over the last few decades, various kinds of drug delivery systems including liposome, nano-capsule, synthetic polymer, and etc have continuously been developed to maximize the therapeutic effect of drugs. However, developing the novel gate-keeping system with a controllable release mechanism for preventing the pre-mature release of cargo is the challenge remained. Herein, we report construction of protease responsive drug delivery system with secured gate keeping effect and propose its application in the control of cancer metastasis. The drug delivery system is mesoporous silica nanoparticle based with its pores tightly capped by α-synuclein protein coated gold nanoparticles via the proteins unique adhesion property on silica surfaces. We have named it as the Particles on a Particle (PoP) system on account of its morphology that smaller particles are covering around a larger particle. In the in vitro cargo release test, using rhodamine6G dye as the model cargo, the PoP showed aorund 80% more effective gate keeping than bare system and the caps were stable at various pH ranges. Furthermore, selective cargo release was achieved by the digestion of α-synuclein by proteases such as trypsin, protease K and chymotrypsin. Protease inhibitor loaded PoP demonstrated its effectiveness in inhibiting the triggering protease indicating its usage in the treatment of the diseases where the level of certain protease is enhanced. As an expansion of this concept, the gate opening of PoP in the presence of matrix metalloproteinase, an endopeptidase known to facilitate the metastasis process of malignant tumor, was tested. Consequently, it was observed that PoP is responsive to matrix metalloproteinase and induced significant cargo release. These results emphasizes the potential of PoP as an enzyme responsive therapeutic nano-carrier which can prevent leaking of cargo and release drugs in response to the changes of patho-physicochemical microenvironment around the target disease.I. Introduction 1 1.1 Drug Delivery System 1 1.1.1 Gate Control 1 1.1.2 Mesoporous Silica Nanoparticle (MSN) 1 1.1.3 Particles on a Particle (PoP) 3 1.2 a-Synuclein and a-AuNP 3 1.2.1. a-Synuclein 3 1.2.2. a-Synuclein Coated Gold Nanoparticle (a-AuNP) 3 1.3. Cancer therapy by Drug Delivery System 7 1.3.1. Cancer Metastasis 7 1.3.2. Matrix Metalloproteinase (MMP) 7 II. Materials and Methods 9 2.1. Materials 9 2.2. Mesoporous Silica Nanoparticle Synthesis 9 2.3. Purification of a-Synuclein 10 2.4. Preparation of the protein coated gold nanoparticles 11 2.5. Formation of Particles on a Particle 11 2.6. Characterization of MSN 12 2.7 UV/VIS Spectroscopy and Fluorescence Spectroscopy 12 2.8 Cargo Release Assay 12 2.9 Enzyme Activity Assay 13 III. Results and Discussions 13 3.1. Characterization of The Synthesized MSN 13 3.2. Confirmation of The Fabricated PoP 15 3.3. Cargo Release Profile of Bare MSN vs. PoP 21 3.4. Effect of pH on The Cargo Release 21 3.5. Protease Induced Gate Opening of PoP 22 3.6. Protease Activity Inhibition by PoP 25 3.7. Matrix Metalloproteinase Induced Release 25 IV. Conclusion 30 V. References 32 국문초록 37Maste