The interactions of mesoporous silica nanoparticles (MSNs) of different particle sizes and surface properties with human red blood cell (RBC) membranes were investigated by membrane filtration, flow cytometry, and various microscopic techniques. Small MCM-41-type MSNs (∼100 nm) were found to adsorb to the surface of RBCs without disturbing the membrane or morphology. In contrast, adsorption of large SBA-15-type MSNs (∼600 nm) to RBCs induced a strong local membrane deformation leading to spiculation of RBCs, internalization of the particles, and eventual hemolysis. In addition, the relationship between the degree of MSN surface functionalization and the degree of its interaction with RBC, as well as the effect of RBC−MSN interaction on cellular deformability, were investigated. The results presented here provide a better understanding of the mechanisms of RBC−MSN interaction and the hemolytic activity of MSNs and will assist in the rational design of hemocompatible MSNs for intravenous drug delivery and in vivo imaging. R ecent advancements in particle size and morphology control of mesoporous materials have led to the creation of nano-and submicrometer-sized mesoporous silica nanoparticles (MSNs). [1][2][3][4][5] The MSN materials with well-ordered cylindrical pore structures, such as MCM-41 and SBA-15, have attracted special interest in the biomedical field. 1 The large surface areas and pore volumes of these materials allow the efficient adsorption of a wide range of molecules, including small drugs, 6-10 therapeutic proteins, 11-13 antibiotics, 14,15 and antibodies. 16 Therefore, these materials have been proposed for use as potential vehicles for biomedical imaging, real-time diagnosis, and controlled delivery of multiple therapeutic agents. [6][7][8]10,[17][18][19][20][21][22][23][24][25] Despite the considerable interest in the biomedical applications of MSNs, relatively few studies have been published on the biocompatibility of the two most common types of MSNs (MCM-41 and SBA-15). [26][27][28][29] Asefa and co-workers reported that the cellular bioenergetics (cellular respiration and ATP levels) were inhibited remarkably by large SBA-15 nanoparticles, but the inhibition was greatly reduced by smaller MCM-41-type nanoparticles. 26 These differences in the disruption of cellular bioenergetics are believed to be caused by the different surface areas, number of surface silanol groups, and/or particle sizes of both types of material. A recent study by Kohane and collaborators on the systemic effects of MCM-41 (particle size ∼150 nm) and SBA-15 (particle size ∼800 nm) MSNs in live animals revealed interesting findings regarding their biocompatibility. 27 While large doses of mesoporous silicas administered subcutaneously to mice appear to be relatively harmless, the same doses given intravenously or intraperitoneally were lethal. 27 A possible reason for the severe systemic toxicity of MSNs when injected intravenously could be the interactions of the nanoparticles with blood cells.Our initial studies...

We report a gold nanoparticle (AuNP)-capped mesoporous silica nanoparticle (Au-MSN) platform for intracellular codelivery of an enzyme and a substrate with retention of bioactivity. As a proof-of-concept demonstration, Au-MSNs are shown to release luciferin from the interior pores of MSN upon AuNP uncapping in response to disulfide-reducing antioxidants and codeliver bioactive luciferase from the PEGylated exterior surface of Au-MSN to Hela cells. The effectiveness of luciferase-catalyzed luciferin oxidation and luminescence emission in the presence of intracellular ATP was measured by a luminometer. Overall, the chemical tailorability of the Au-MSN platform to retain enzyme bioactivity, the ability to codeliver enzyme and substrate, and the potential for imaging tumor growth and metastasis afforded by intracellular ATP-and glutathione-dependent bioluminescence make this platform appealing for intracellular controlled catalysis and tumor imaging. ABSTRACT: We report a gold nanoparticle (AuNP)-capped mesoporous silica nanoparticle (Au-MSN) platform for intracellular codelivery of an enzyme and a substrate with retention of bioactivity. As a proof-of-concept demonstration, Au-MSNs are shown to release luciferin from the interior pores of MSN upon AuNP uncapping in response to disulfide-reducing antioxidants and codeliver bioactive luciferase from the PEGylated exterior surface of Au-MSN to Hela cells. The effectiveness of luciferase-catalyzed luciferin oxidation and luminescence emission in the presence of intracellular ATP was measured by a luminometer. Overall, the chemical tailorability of the Au-MSN platform to retain enzyme bioactivity, the ability to codeliver enzyme and substrate, and the potential for imaging tumor growth and metastasis afforded by intracellular ATP-and glutathionedependent bioluminescence make this platform appealing for intracellular controlled catalysis and tumor imaging.

vi CHAPTER 1. DISSERTATION ORGANIZATION 1 CHAPTER 2. MESOPOROUS SILICA NANOPARTICLES FOR DRUG DELIVERY AND CONTROLLED RELEASE 2 Abstract 2 iii 7.2 In planta Delivery 32 8. Conclusion 34 References 35 CHAPTER 3. INTERACTION OF MESOPOROUS SILICA NANOPARTICLES WITH HUMAN RED BLOOD CELL MEMBRANES: SIZE AND SURFACE EFFECTS 41 Abstract 41 1. Introduction 41 2. Results and Discussion 43 2.1. Size-and surface-dependent MSN interaction with RBC membranes 43 2.2. Size-and surface-dependent engulfment of MSNs by RBCs 48 2.3. Surface functionality effects on RBC-MSN interaction 50 2.4. Effect of RBC-MSN interaction on RBC deformability 53 3. Conclusion 54 4. Methods 55 Acknowledgement 58 References 59 Appendix 63 CHAPTER 4. MESOPOROUS SILICA NANOPARTICLE TETHERED SINGLE SITE PLATINUM CATALYSTS FOR THE FUNCTIONALIZATION OF ETHYLENE 69 Abstract 69 Article 69 References 74 Appendix 75 CHAPTER 5. ONE-POT OXIDATIVE ESTERIFICATION OF ALLYL ALCOHOL CO-CATALYZED BY ALCOHOL DEHYDROGENASE ENZYME AND MESOPOROUS SILICA NANOPARTICLE SUPPORTED GOLD NANOPARTICLES 79 Abstract 79 iv 1. Introduction 79 2. Materials and Methods 81 3. Results and Discussion 84 4. Conclusion 92 References 93 CHAPTER 6. LUCIFERASE AND LUCIFERIN CO-IMMOBILIZED MESOPOROUS SILICA NANOPARTICLE MATERIALS FOR INTRACELLULAR BIOCATALYSIS 95 Abstract 95 Article 95 Acknowledgement 104 References 105 Appendix 107 CHAPTER 7. GENERAL CONCLUSIONS 117 v ACKNOWLEDGEMENTS I would like to convey my sincere thanks and deep appreciation to those who have supported and inspired me during these years. First and foremost, I am deeply indebted to my major professor, Dr. Victor Shang-Yi Lin, whose enthusiasm, encouragement, creativity, patience and dedication to science exemplified to me what a scientist should be. It is my supreme honor to have been a graduate student in his research group. Although he is no longer with us, his words and deeds will continue to guide me in my future life.

To establish a new method for tracking the interaction of nanoparticles with chemical cleaving agents, we exploited the optical effects caused by attaching 5–10 nm gold nanoparticles with molecular linkers to large mesoporous silica nanoparticles (MSN). At low levels of gold loading onto MSN, the optical spectra resemble colloidal suspensions of gold. As the gold is removed, by cleaving agents, the MSN revert to the optical spectra typical of bare silica. Time-lapse images of gold-capped MSN stationed in microchannels reveal that the rate of gold release is dependent on the concentration of the cleaving agent. The uncapping process was also monitored successfully for MSN endocytosed by A549 cancer cells, which produce the cleaving agent glutathione. These experiments demonstrate that the optical properties of MSN can be used to directly monitor cleaving kinetics, even in complex cellular settings.

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Article Acknowledgement References Appendix: Supporting Information CHAPTER 3 FUNCTIONALIZED MESOPOROUS SILICA NANOPARTICLE BASED HETEROGENEOUS CATALYST FOR C-H BOND ACTIVATION REACTION 1. Introduction 2. Experimental methods 2.1. Synthesis of Bpy-amide-TES 2.2. Post-grafting method iii 2.3. Co-condensation method 3. Results and discussion 4. Conclusion References CHAPTER 4. GENERAL CONCLUSIONS iv ACKNOWLEDGEMENT I would like to convey my sincere thanks and deep appreciation to those who have supported and inspired me during these years. First and foremost, I am deeply indebted to my major professor, Dr. Victor Shang-Yi Lin, whose enthusiasm, encouragement, creativity, patience and dedication to science. exemplified to me what a scientist should be. It is my supreme honor to be a graduate student in his research group. Although he is no longer with us, his words and deeds will continue to guide me in my future life. My sincere gratitude also extends to my advisor Dr. Brian G. Trewyn, for his guidance for my research and his generous support with my degree completion.