RNA interference (RNAi) has long been pursued for its therapeutic potential. Sequence-specific knockdown of gene expression requires that small interfering RNA (siRNA) gain access to cellular cytoplasm, presenting difficulties for both the transport of nucleic acids to cells and their voyage across cellular membranes. Numerous materials are under development as siRNA delivery vehicles to address this need. The carbohydrate dextran has been incorporated into amine-functionalized sil- ica nanoparticles (Dex-SiO2-NPs), enhancing their biocompatibility and success as siRNA delivery vehicles. Inspired by the work of Stober and others, reagent concentrations in the synthesis of Dex- SiO2-NPs have been adjusted to tune nanoparticle diameter. The size, shape, and morphology of Dex-SiO2-NPs have been characterized using transmission electron microscopy (TEM) and energy dispersive x-ray spectroscopy (EDS). These methods have revealed that Dex-SiO2-NPs decrease in silicon density toward their centers, when compared with SiO2-NPs. Thermal and porosity analysis were used to profile Dex-SiO2-NPs both containing dextran and after its removal by calcination. Having measured an increase in mesopores and decrease in micropores with calcination, it has been concluded that dextran serves as a porogen in Dex-SiO2-NP synthesis. Not only does dextran imbue these materials with unique morphology, it also enhances their function as delivery vehicles. Dex-SiO2-NPs improve enhanced green fluorescent protein (EGFP) supression compared to silica nanoparticles synthesized in the absence of dextran in human lung and kidney cells in vitro.
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