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Nanotech News
Understanding How a Nanoparticle's Surface Affects Cell Uptake One promising method for building nanoparticles is through electrostatic, layer-by-layer self-assembly. This approach to nanoparticle construction yields well-designed shells whose thickness and surface composition can be determined in advance. In addition, nanoparticle shells built in this manner can be "opened" and "closed" by manipulating environmental variables, allowing these particles to be loaded with a wide variety of payload molecules, including: drugs, DNA, enzymes and imaging markers. What is not well understood about these particles is how their surface composition affects their interactions with cells, a key consideration for drug delivery applications. Initial work aimed at filling that information gap has now been published online in the Journal of Biomedical Materials Research Part A. Researchers at Case Western Reserve University, led by collaborators Jinming Gao, Ph.D., and David Boothman, Ph.D., examined how various physical and chemical properties, including surface charge and composition, altered the interaction of polyelectrolyte nanoparticles with breast cancer cells. The researchers also examined how different polymer coatings, which would be used to prevent proteins from sticking to the particles, affected nanoparticle interactions with breast cancer cells. The researchers found that nanoparticles with a wide variety of compositions were readily taken up by cancer cells. When incubated with serum, however, the particles accumulated proteins on their surfaces that dramatically altered their interactions with cancer cells. The researchers then modified the nanoparticle surfaces using polyethylene glycol-polyethyleneimine (PEG-PEI) copolymers of varying PEG and PEI compositions and again measured the resulting particles' uptake by cells. These experiments showed that increasing the ratio of polyethyleneimine to polyethylene glycol in the polymer coating increased the uptake of the resulting nanoparticles by breast cancer cells. From these results, the investigators concluded that choosing the exact composition of a nanoparticle polymer coating can both reduce protein absorption and improve cell uptake. This work, funded by the National Cancer Institute, is detailed in a paper titled "Interactions between self-assembled polyelectrolyte shells and tumor cells." This paper was published online in advance of print publication. An abstract is available at the journal's website. |
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