Purpose: Surface modification of systemically-administered nanoparticles by plasma proteins is a major factor in site-specific delivery and cellular interactions. The main goal of this project was to evaluate how the protein corona affects lipid nanoparticle (LNP)-cell interactions and subsequent transfection of small interfering RNA (siRNA).
Approach: Four types of LNPs formulated with C14 and C18 carbon chain length fatty acids and poly(ethylene glycol) (PEG) for siRNA encapsulation. The nanoparticles were incubated with HepG2 cells, with or without the addition of 5% fetal bovine serum (FBS) in the media. Cellular uptake in HepG2 cells was observed with fluorescence confocal microscopy; gene silencing was confirmed by PCR. Additionally, protein corona composition on LNPs incubated with FBS was investigated by SDS-PAGE and mass spectrometry.
Results: The relative size, charge, and morphology of the formulations were considered identical. However, distinct differences in transfection efficiencies were observed. At the same siRNA concentrations, C14-PEG with FBS showed the highest gene knockdown of 80-90 while C18 NPs showed almost no knockdown. For C18 LNPs, gene silencing was hindered by FBS addition; whereas for C14 LNPs, FBS facilitated silencing. SDS-PAGE and mass spectrometry confirm differential serum protein corona composition on LNPs.
Conclusions: The four types of LNPs showed different cellular uptake in a model system based on the surface protein modification from serum. Further understanding of the protein corona and correlation to tailored nanoparticle surface chemistry would provide an intriguing opportunity for systemic targeting and cellular delivery.