Nanoparticles in the Biological Context: Surface Morphology and Protein Corona Formation

A recent paper demonstrated that the formation of a protein corona is not a general property of all types of nanosized objects. In fact, it varies between a massive aggregation of plasma proteins onto the nanoparticle down to traces (e.g., a few proteins per 10 nanoparticles), which can only be determined by mass spectrometry in comparison to appropriate negative controls and background subtraction. Here, differences between various types of nanosized objects are discussed in order to determine general structure-property-relations from a physico-chemical viewpoint. It is highlighted that "not all nanoparticles are alike" and shown that their internal morphology, especially the difference between a strongly hydrated/swollen shell versus a sharp "hard" surface and its accessibility, is most relevant for biomedical applications.