Layer-by-layer microcapsules are composed of alternating layers of oppositely charged molecules. These microstructures are beneficial for use in nanomedicine because they can be easily modified. For example, the different layers can be tuned to carry the necessary bioactive molecules while also targetinga desired tissue and triggering incorporation of the bioactive molecule into the cell.
Targeting moieties can be incorporated into the microstructures to specifically target cells of interest. This method is useful, but it relies on a deep knowledge of the unique ligands on the tissue of interest, and this knowledge isn’t always available or sufficient. Therefore, magnetically targeted delivery of molecules is a desirable technique for directing microcapsules to the correct location. Once the microcapsule reaches the correct location it must release its contents into the targeted cells. Recent work demonstrates that the addition of magnetite nanoparticles into a layer-by-layer microcapsule increases the delivery of luciferase enzyme and plasmid DNA to cultured cells.
The scientists incorporated magnetite nanoparticles as a middle layer between biodegradable microcapsules. The finished microcapsules carried luciferase enzyme and plasmid DNA. The addition of the magnetite increased the density of the microcapsules and increased the sedimentation rate out of suspension and onto cells in a culture dish. Additionally, as measured by a bioluminescence assay, the magnetite increased the delivery rate of the luciferase enzyme to the cells. The transfection of cells was improved by the use of microcapsules containing magnetite. Finally, the delivery of both luciferase and plasmid was significantly increased when a magnetic field was applied to the dish.
This work has not been tested in vivo, but the group did biocompatibility testing on cultured cells and displayed no toxicity at low concentrations. This work holds promise in the realm of biotechnology and could be a useful way to label and track cells.
Improved and targeted delivery of bioactive molecules to cells with magnetic layer-by-layer assembled microcapsules. Anton M. Pavlov, Samantha A. Gabriel, Gleb B. Sukhorukov, David J. Gould.Nanoscale, 2015.
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