Mesoporous silica particles (MSP) are a new development in nanotechnology. Covalent modification of the surface of the silica is possible both on the internal pore and on the external particle surface. It allows the design of functional nanostructured materials with properties of organic, biological and inorganic components. Research and development are ongoing on the MSP, which have applications in catalysis, drug delivery and imaging. The most recent and interesting advancements in size, morphology control and surface functionalization of MSP have enhanced the biocompatibility of these materials with high surface areas and pore volumes. In the last 5 years several reports have demonstrated that MSP can be efficiently internalized using in vitro and animal models. The functionalization of MSP with organic moieties or other nanostructures brings controlled release and molecular recognition capabilities to these mesoporous materials for drug/gene delivery and sensing applications, respectively. In this study different MSP have been tested: silica-FITC MSP and silica-folate-FITC MSP. Folic acid was used as the targeting ligand because -folate receptor is observed to be up-regulated in various types of human cancers. We have evaluated by confocal laser scanning microscopy (CLSM) the intracellular localization of FITC-loaded MSP in two different cancer cell lines: IGROV-1 (ovarian carcinoma) and A549 (lung adenocarcinoma) characterized by a different expression of folate receptor alpha. Our results demonstrate that silica nanoparticles localize into the cytoplasm of A549 and IGROV-1 cell lines after 1, 6 and 24 hours of treatment and present a perinuclear localization. Additionally the treated cells were examined cross-sectionally in order to confirm that the MSP were indeed internalized by the cells and not simply bound on the surface membrane. Flow cytometry was used for the quantification of fraction of cells that had internalized nanoparticles. The cellular uptake of silica nanoparticles was observed with both cell lines and folate modification on the silica nanoparticles increased the particles uptake by A549 and IGROV-1 cells. The over-expression of folate receptor may facilitate the recognition of the folate-modified nanoparticles and increase the uptake through folate receptor-mediated endocytosis Electron microscopy experiments also confirmed that silica nanoparticles are able to enter into tumor cells. The particles are progressively internalized into the cell cytoplasm starting from 15 minutes after treatment and after 30 minutes are completely internalized.
Cavaletti, G., Ceresa, C., Nicolini, G., Miloso, M., Cundari, S., Pasqua, L. (2009). Confocal laser scanning microscope and ultrastructural study of the intracellular localization of fluorescein-loaded mesoporous silica carriers. Intervento presentato a: LXIII meeting of the italian society of anatomy and histology, Torino.
Confocal laser scanning microscope and ultrastructural study of the intracellular localization of fluorescein-loaded mesoporous silica carriers
CAVALETTI, GUIDO ANGELOPrimo
;CERESA, CECILIASecondo
;NICOLINI, GABRIELLA;MILOSO, MARIAROSARIA;
2009
Abstract
Mesoporous silica particles (MSP) are a new development in nanotechnology. Covalent modification of the surface of the silica is possible both on the internal pore and on the external particle surface. It allows the design of functional nanostructured materials with properties of organic, biological and inorganic components. Research and development are ongoing on the MSP, which have applications in catalysis, drug delivery and imaging. The most recent and interesting advancements in size, morphology control and surface functionalization of MSP have enhanced the biocompatibility of these materials with high surface areas and pore volumes. In the last 5 years several reports have demonstrated that MSP can be efficiently internalized using in vitro and animal models. The functionalization of MSP with organic moieties or other nanostructures brings controlled release and molecular recognition capabilities to these mesoporous materials for drug/gene delivery and sensing applications, respectively. In this study different MSP have been tested: silica-FITC MSP and silica-folate-FITC MSP. Folic acid was used as the targeting ligand because -folate receptor is observed to be up-regulated in various types of human cancers. We have evaluated by confocal laser scanning microscopy (CLSM) the intracellular localization of FITC-loaded MSP in two different cancer cell lines: IGROV-1 (ovarian carcinoma) and A549 (lung adenocarcinoma) characterized by a different expression of folate receptor alpha. Our results demonstrate that silica nanoparticles localize into the cytoplasm of A549 and IGROV-1 cell lines after 1, 6 and 24 hours of treatment and present a perinuclear localization. Additionally the treated cells were examined cross-sectionally in order to confirm that the MSP were indeed internalized by the cells and not simply bound on the surface membrane. Flow cytometry was used for the quantification of fraction of cells that had internalized nanoparticles. The cellular uptake of silica nanoparticles was observed with both cell lines and folate modification on the silica nanoparticles increased the particles uptake by A549 and IGROV-1 cells. The over-expression of folate receptor may facilitate the recognition of the folate-modified nanoparticles and increase the uptake through folate receptor-mediated endocytosis Electron microscopy experiments also confirmed that silica nanoparticles are able to enter into tumor cells. The particles are progressively internalized into the cell cytoplasm starting from 15 minutes after treatment and after 30 minutes are completely internalized.
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