Mapping and identification of soft corona proteins at nanoparticles and their impact on cellular association

The current understanding of the biological identity that nanoparticles may acquire in a given biological milieu is mostly inferred from the hard component of the protein corona (HC). The composition of soft corona (SC) proteins and their biological relevance have remained elusive due to the lack of analytical separation methods. Here, we identify a set of specific corona proteins with weak interactions at silica and polystyrene nanoparticles by using an in situ click-chemistry reaction. We show that these SC proteins are present also in the HC, but are specifically enriched after the capture, suggesting that the main distinction between HC and SC is the differential binding strength of the same proteins. Interestingly, the weakly interacting proteins are revealed as modulators of nanoparticle-cell association mainly through their dynamic nature. We therefore highlight that weak interactions of proteins at nanoparticles should be considered when evaluating nano-bio interfaces.


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Life sciences study design
All studies must disclose on these points even when the disclosure is negative. No sample size calculations were performed for this study as we did not perform any in vivo or patient analysis. No group comparisons were made in order to determine a specified effect. Sample size for in vitro cell cultures and other experiments are indicated in each figure legend. The sample size were chosen so we had enough data to do statistical analysis.
No data were excluded from analysis; all analyses were performed as described in the Materials and Methods All cell data and other findings were obtained by three technical replicates and for most analysis assays were repeated two or three times batches. All experiments findings were reliably reproducible.
n/a. This study was not concerned with individuals but with populations of cell lines; however, the differentiated THP-1 cells and hCMEC/D3 cells were randomly chosen from each batch of cultured cells for further analysis.
n/a. The investigators were not blind to group allocation during data collection as the data collection and the subsequent analysis were not sensitive to potential bias.
THP-1 monocyte cells (a human acute monocyte leukemia cell line) was obtained from the German Collection of Microorganisms and Cell Cultures (DSMZ, ACC 16).hCMEC/D3 cells were obtained from sigmaaldrich (SCC066).
The cell lines were not authenticated.

Negative for Mycoplasma
No misidentified cell lines were used.