Cellular internalization of inorganic, lipidic and polymeric nanoparticles is of great significance in the quest to develop effective formulations for the treatment of high morbidity rate diseases. Understanding nanoparticle-cell interactions plays a key role in therapeutic interventions, and it continues to be a topic of great interest to both chemists and biologists. The mechanistic evaluation of cellular uptake is quite complex and is continuously being aided by the design of nanocarriers with desired physico-chemical properties. The progress in biomedicine, including enhancing the rate of uptake by the cells, is being made through the development of structure-property relationships in nanoparticles. We summarize here investigations related to transport pathways through active and passive mechanisms, and the role played by physico-chemical properties of nanoparticles, including size, geometry or shape, core-corona structure, surface chemistry, ligand binding and mechanical effects, in influencing intracellular delivery. It is becoming clear that designing nanoparticles with specific surface composition, and engineered physical and mechanical characteristics, can facilitate their internalization more efficiently into the targeted cells, as well as enhance the rate of cellular uptake.
Keywords: active/passive transport; cellular uptake; intracellular delivery; nanoparticles; physico-chemical properties.