Polymer Nanoparticles and Their Cellular Interactions

Abstract

During the past decade, nanoparticles (NPs) and their interaction with human cells have been a focus of many investigations. The main advantages of NPs over other nanoparticulate systems (such as liposomes and micelles) are their increased colloidal stability, chemical resistance, and simple formulation procedures. Progress in the field of understanding and harnessing the interactions of polymeric NPs with different cell types is discussed and reviewed. Attention is focused on NPs synthesized by the miniemulsion process, as this route has proved to be the most versatile for formulating different polymeric materials via this platform technology. Nanomaterials are of interest only if they make use of the specific properties of supramolecular assemblies and nanomaterials, so that hitherto inaccessible effects can be exploited for new applications. Examples for such new properties are superparamagnetism or the high surface area that is valuable for catalysis and adsorption. Although not an effect triggered by quantum mechanics, the uptake of NPs into a wide variety of cells seems to be specific for materials in the range of 50–200 nm. Uptake can be further enhanced by surface modifications (positive or negatively charged side groups of the polymers, amino acids or specific peptides/proteins). Factors such as size, surface properties, cell type and endocytotic pathways enable the optimization of labeling and selection of cells and NPs for applications both in vitro and in vivo. Keywords: polymeric nanoparticle; polymeric nanocapsules; MRI contrast agent; cell tracking; endocytosis; miniemulsion; mesenchymal stem cell; differentiation