Victor Shang-Yi Lin

Ordered Mesoporous Polymer−Silica Hybrid Nanoparticles as Vehicles for the Intracellular Controlled Release of Macromolecules

A two-dimensional hexagonal ordered mesoporous polymer-silica hybrid nanoparticle (PSN) material was synthesized by polymerization of acrylate monomers on the surface of SBA-15 mesoporous silica nanoparticles. The structure of the PSN material was analyzed using a series of different techniques, including transmission electron microscopy, powder X-ray diffraction, and N(2) sorption analysis. These structurally ordered mesoporous polymer-silica hybrid nanoparticles were used for the controlled release of membrane-impermeable macromolecules inside eukaryotic cells. The cellular uptake efficiency and biocompatibility of PSN with human cervical cancer cells (HeLa) were investigated. Our results show that the inhibitory concentration (IC(50)) of PSN is very high (>100 μg/mL per million cells), while the median effective concentration for the uptake (EC(50)) of PSN is low (EC(50) = 4.4 μg/mL), indicating that PSNs are fairly biocompatible and easily up-taken in vitro. A membrane-impermeable macromolecule, 40 kDa FITC-Dextran, was loaded into the mesopores of PSNs at low pH. We demonstrated that the PSN material could indeed serve as a transmembrane carrier for the controlled release of FITC-Dextran at the pH level inside live HeLa cells. We believe that further developments of this PSN material will lead to a new generation of nanodevices for intracellular controlled delivery applications.

Reversible binding and fluorescence energy transfer between surface-derivatized CdS nanoparticles and multi-functionalized fluorescent mesoporous silica nanospheres

Abstract A MCM-41 types of Mesoporous Silica Nanosphere material ( MSN ) covalently anchored with a fluorescent dye (Texas Red™) is synthesized. The Texas-Red-doped MSNs is also functionalized with a second organic group, i.e., mercaptopropyl or aminopropyl functionalities. These organic groups of the resulting bifunctional MSN s are utilized as reversible linkers to entrap two corresponding surface-derivatized cadmium sulfide ( CdS ) nanoparticles. The kinetics of encapsulation and release as well as the photophysical properties of the photoluminescent quantum dots and the MSN composites are investigated by examining the fluorescence resonance energy transfer between the two species. We demonstrated that the fluorescence energy transfer between CdS and Texas Red molecules can be “ switched off” by chemically cleaving the covalent linkage between the mesopore-entrapped CdS and the fluorescent MSN . Our results indicated that these MSN materials provided with proper pore-surface functional groups could serve as reversible hosts to entrap and release surface-derivatized cadmium sulfide nanoparticles.