Investigation of protein corona formed on upconverting nanoparticles

Abstract

Currently, the use of multifunctional upconverting nanoparticles (UCNPs) is rapidly growing in the view of their bioimaging, drug delivery and therapy application possibilities [1]. In order to create nanomedicines it is crucial to understand UCNPs interaction with biological environment. When nanoparticles (NPs) enter biological media they rapidly interact with biomolecules and proteins that form the so-called protein corona. Furthermore, when NPs enter blood circulatory system they interplay with blood plasma proteins, which form plasma protein corona [2]. Detailed understanding of the interplay between NPs and blood plasma is crucial for their application in cancer theranostics. Plasma, compared to fetal bovine serum, is more beneficial for protein corona studies and is more in-vivo-like model system. However, only a handful of papers report on the interaction between plasma and NPs [3]. It should be noted that blood plasma requires anticoagulants that inhibit plasma from clotting in comparison with serum which does not. In addition, any surface modification of NP will alter size and protein composition of corona around the NP. Therefore, any studies on protein corona formation around different NP’s coatings are very important to find the most suitable NP composition for theranostics. This work aims at the investigation of the protein corona around citrate, SiO2 and phospholipid coated LiYF4:Yb3+, Tm3+ UCNPs, and corona’s impact on cellular internalization. Photophysical characteristics of UCNPs in media containing human blood plasma were studied along with UCNPs’ physico-chemical interaction with proteins and biologically active molecules. Remarkably, the surface coating of the UCNPs, as well as the isoelectric point of the plasma proteins, are found to play significant roles in determining the UCNP coronas. All in all, knowledge about protein corona around UCNPs is imperative in developing novel strategies for cancer diagnostics and therapy.