Background: When nanoparticles (NPs) are applied into a biological fluid, such as
blood, proteins bind rapidly to their surface forming a so-called "
protein corona". These
proteins are strongly attached to the NP surface and confers them a new biological identity that is crucial for the biological response in terms of body biodistribution, cellular uptake, and toxicity. The corona is dynamic in nature and it is well known that the composition varies in dependence of the physicochemical properties of the NPs. In the present study we investigated the
protein corona that forms around
poly(lactide-co-glycolide) (PLGA) NPs at different serum concentrations using two substantially different serum types, namely
fetal bovine serum (FBS) and human serum. The corona was characterized by means of
sodium dodecylsulfate
polyacrylamide gel electrophoresis (SDS-PAGE), Bradford
protein assay, zeta potential measurements, and liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). Additionally, the time-dependent cell interaction of PLGA NPs in the absence or presence of a preformed
protein corona was assessed by in vitro incubation experiments with the human
liver cancer cell line HepG2. Results: Our data revealed that the physiological environment critically affects the
protein adsorption on PLGA NPs with significant impact on the NP-cell interaction. Under comparable conditions the
protein amount forming the
protein corona depends on the serum type used and the serum concentration. On PLGA NPs incubated with either FBS or human serum a clear difference in qualitative
corona protein composition was identified by SDS-PAGE and LC-MS/MS in combination with bioinformatic
protein classification. In the case of human serum a considerable change in corona composition was observed leading to a concentration-dependent desorption of abundant
proteins in conjunction with an adsorption of high-affinity
proteins with lower abundance. Cell incubation experiments revealed that the respective corona composition showed significant influence on the resulting nanoparticle-cell interaction. Conclusion: Controlling
protein corona formation is still a challenging task and our data highlight the need for a rational future experimental design in order to enable a prediction of the corona formation on nanoparticle surfaces and, therefore, the resulting biodistribution in the body.