Aspherical, Nanostructured Microparticles for Targeted Gene Delivery to Alveolar Macrophages

Abstract

Introducing novel shapes to particulate carrier systems adds unique features to modern drug and gene delivery. Depending on the route of administration, particle geometry can influence deposition and fate within biological environments. In this work, a template-assisted engineering technique is applied, providing full control of size and shape in the preparation of aspherical, nanostructured microparticles. Based on the interconnection of nanoparticles, stabilized by a functional layer-by-layer (LbL) coating, the resulting cylindrical micrometer architecture is especially qualified for pulmonary delivery. Designed as gene delivery system, plasmid-DNA (pCMV-luciferase) and branched polyethylenimine are used to reach both structural integrity of the carrier system and delivery of genes into the cells of interest. Due to their size, particles are exclusively taken up by phagocytes, which also adds a targeting effect to the introduced system. The luciferase expression is demonstrated in macrophages showing increasing levels over a time period of at least 7 d. Furthermore, it is shown for the first time that the expression is depending on the LbL design. From in vivo experiments, corresponding luciferase expression is observed in mice alveolar macrophages. Combining site specific transport with the possibility of genetically engineering immunocompetent phagocytes, the presented system offers promising potential to improve applications for cell-based immunotherapy.

Silica nanoparticles of microrods enter lung epithelial cells

“…The intention of this short report was to highlight that this novel drug delivery system may not only reach macrophages but also enter epithelial cells. The corncob-like microrods have previously been reported to be engulfed by macrophages and to successfully transfect macrophages ( 2 ); however, due to their dimensions, they were considered incapable of entering epithelial cells. The epithelial cells used were A549 cells.…”

“…Cells were cultivated at 37°C in a humidified atmosphere with 5% CO 2 in RPMI-1640 medium with 10% fetal bovine serum (Merck KGaA), 100 units ml −1 penicillin and 100 µg ml −1 streptomycin. The microparticles were produced from amorphous silica nanoparticles (Polysciences GmbH, Eppelheim, Germany) as described previously ( 2 ) and had a length of 10 µm and diameter of 3 µm. The microparticles were suspended in aqua dest distilled water, and the number of particles per µl were determined by the use of a Neubauer counting chamber.…”

“…However, there remains to be a need for safe and efficient gene therapy carrier systems for different cell types. Recently, a novel carrier system was developed ( 2 ) and implemented for the delivery of drugs or plasmids to human macrophages ( 3 ). A corncob-like microparticle composed of amorphous silica nanoparticles was created and loaded with a gene construct for luciferase.…”

“…Those particles could serve as a gene delivery system to phagocytosing cells in vitro and in vivo ; notably, it was demonstrated that the particles were engulfed by professional phagocytes, alveolar macrophages. Days after engulfment of the microparticles, the alveolar macrophages were confirmed to be transfected with luciferase ( 2 ). Thus macrophages, as the primary phagocytes, may even engulf these relatively large microparticles of 10 µm in length and 3 µm in width.…”

Photo-Enhanced Delivery of Genetic Material Using Curcumin Loaded Composite Nanocarriers

“…Liposomal encapsulation increases the bioavailability, biocompatibility and bio efficacy of the therapeutic substances ranging from drugs to biomolecules such as DNA, siRNA and other oligonucleotides [11][12][13]. Poly Ethylen Imine (PEI) on the other hand is a proven polymer for gene delivery and is often considered as a gold standard for transfection [14][15][16]. A combination of PEI/nucleic acid polyplexes and liposomes called Lipopolyplexes (LPP) has been proven to increase the efficiency of gene delivery and decrease the toxicity associated with polyethylenimine [17][18][19].…”