The local interference of cytokine signaling mediated by siRNA-loaded nanoparticles might be a promising new therapeutic approach to dampen inflammation during pulmonary diseases. For the local therapeutic treatment of pulmonary inflammation, we produced multi-shell nanoparticles consisting of a calcium phosphate core, coated with siRNAs directed against pro-inflammatory mediators, encapsulated into poly(lactic-co-glycolic acid), and coated with a final outer layer of polyethylenimine. Nasal instillation of nanoparticles loaded with a mixture of siRNAs directed against different cytokines to mice suffering from T1 cell-mediated lung inflammation, or of siRNA directed against NS-1 in an influenza infection model led to a significant reduction of target gene expression which was accompanied by distinct amelioration of lung inflammation in both models. Thus, this study provides strong evidence that the specific and local modulation of the inflammatory response by CaP/PLGA nanoparticle-mediated siRNA delivery could be a promising approach for the treatment of inflammatory disorders of the lung.
The pro-inflammatory cytokine TNF-a was silenced by treating MODE-K cells with triple-shell calcium phosphate nanoparticles. These consisted of a core of calcium phosphate, followed by a shell of siRNA, then a shell of calcium phosphate to protect the siRNA from nucleases and finally a shell of poly(ethyleneimine) for colloidal stabilization and to give the particles a positive charge. First, the gene silencing efficiency was demonstrated with HeLa-eGFP cells and determined by manually counting the green fluorescent cells, by quantitative FACS analysis of the green fluorescence per cell, and by qPCR at the RNA level. Cell counting gave the highest degrees of eGFP expression, but FACS and qPCR gave more accurate data as they are not probing the cell colour (green or not green) only as yes/no property. This was transposed to the inflammatory relevant mouse cell line MODE-K that was previously stimulated with LPS to induce the expression of TNF-a. By application of the nanoparticles, the TNF-a expression was reduced almost to the original level, as shown by qPCR. Thus, calcium phosphate nanoparticles are well suited to reduce inflammatory reactions by silencing the corresponding cytokines, e.g. TNF-a.
We report the synthesis, characterization, photophysical investigations, and cell‐uptake studies of luminescent silica nanoparticles incorporating covalently linked visible‐light‐excitable Eu3+ complexes. Visible‐light excitation was accomplished by using highly conjugated carbazole‐based β‐diketonate ligands. Covalent incorporation of the Eu3+ complexes into the silica nanoparticles was achieved by modification of the bidentate phosphine oxide 4,6‐bis(diphenylphosphoryl)‐10H‐phenoxazine (DPOXPO), which was used as the neutral donor for the Eu3+ ion. The surface amine functionalization of the nanoparticles was carried out using aminopropyltriethoxysilane (APTES). The prepared nanoparticles (Eu@Si‐OH and Eu@Si‐NH2) are around 35–40 nm in diameter, monodisperse, stable in aqueous dispersion, and also retain the luminescent properties of the incorporated Eu3+ complex. The synthesized nanoparticles exhibit a promising luminescence quantum yield of 38 % and an excited‐state lifetime of 638 µs at physiological pH. The photobleaching experiments revealed that the developed nanoparticles are more photostable than the parent Eu3+ complex 1. In vitro experiments with Eu@Si‐NH2 nanoparticles on HeLa cells showed that they are biocompatible and are readily taken up by cells.
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