Over the past two decades, numerous types of nanoparticles (NPs) have been developed for medical applications; however only a few nanomedicines are actually available on the market. One reason is the lack of understanding and data concerning the NP fate and their behavior upon contact with biological media and cell membranes. Biomimetic membrane models are interesting tools to approach and understand NPs–cell membrane interactions. The use of these models permits one to control physical and chemical parameters and to rapidly compare membrane types and the influence of different media conditions. The interactions between NPs and cell membranes can be qualified and quantified using analytical and modeling methods. In this review, the major studies concerning NPs–cell membrane models and associated methods are described. The advantages and drawbacks for each method are compared for the different models. The key mechanisms of interactions between NPs and cell membranes are revealed using cell membrane models and are interrogated in comparison with the NP behavior in cellulo or in vivo. Investigating the interactions between NPs and cell membrane models is now proposed as an intermediate step between physicochemical characterization of NPs and biological assays.

The formation of a protein corona around nanoparticles can influence their toxicity, triggering cellular responses that may be totally different from those elicited by pristine nanoparticles. The main objective of this study was to investigate whether the species origin of the serum proteins forming the corona influences the in vitro toxicity assessment of silica nanoparticles. Coronas were preformed around nanoparticles before cell exposures by incubation in fetal bovine (FBS) or human (HS) serum. The compositions of these protein coronas were assessed by nano-LC MS/MS. The effects of these protein-coated nanoparticles on HepG2 cells were monitored using real-time cell impedance technology. The nanoparticle coronas formed in human or fetal bovine serum comprised many homologous proteins. Using human compared with fetal bovine serum, nanoparticle toxicity in HepG2 cells decreased by 4-fold and 1.5-fold, when used at 50 and 10μg/mL, respectively. It is likely that “markers of self” are present in the serum and are recognized by human cell receptors. Preforming a corona with human serum seems to be more appropriate for in vitro toxicity testing of potential nanocarriers using human cells. In vitro cytotoxicity assays must reflect in vivo conditions as closely as possible to provide solid and useful results.

Mesoporous Silica Nanoparticles (MSN) are now considered as multifunctional platforms for pharmaceutical development. The goal of this study was to optimize a synthesis procedure to obtain reproducible monodisperse magnetic core@shell Fe₃O₄@MSN with different coatings and study their uptake by cells. 100 nm core@shell nanoparticles with a unique 18 nm magnetic core were synthesized and covered with PEG groups or coated with a lipid bilayer in a controlled manner and their cellular fate was investigated. Both PEG and lipidic coated nanoparticles exhibit a low toxicity when incubated with Hep-G2 cells compared to pristine ones. Furthermore, the different real-time impedance cellular profiles that were observed and the particles uptake by the cells investigated by TEM suggest different internalization mechanisms or uptake kinetics depending on MSN coverage. This study is a first essential step to ensuring the preparation of well-defined nanomaterials for medical applications; it is considered as a crucial step to be able to perform detailed research about cellular trafficking and signaling pathways.

Magnetic mesoporous silica nanoparticles (M-MSNs) are a promising class of nanoparticles for drug delivery. However, a deep understanding of the toxicological mechanisms of action of these nanocarriers is essential, especially in the liver. The potential toxicity on HepaRG cells of pristine, pegylated (PEG), and lipid (DMPC) M-MSNs were compared. Based on MTT assay and real-time cell impedance, none of these NPs presented an extensive toxicity on hepatic cells. However, we observed by transmission electron microscopy (TEM) that the DMPC and pristine M-MSNs were greatly internalized. In comparison, PEG M-MSNs showed a slower cellular uptake. Whole gene expression profiling revealed the M-MSNs molecular modes of action in a time- and dose-dependent manner. The lowest dose tested (1.6 µg/cm²) induced no molecular effect and was defined as ‘No Observed Transcriptional Effect level.’ The dose 16 µg/cm² revealed nascent but transient effects. At the highest dose (80 µg/cm²), adverse effects have clearly arisen and increased over time. The limit of biocompatibility for HepaRG cells could be set at 16 µg/cm² for these NPs. Thanks to a comparative pathway-driven analysis, we highlighted the sequence of events that leads to the disruption of hepatobiliary system, elicited by the three types of M-MSNs, at the highest dose. The Adverse Outcome Pathway of hepatic cholestasis was implicated. Toxicogenomics applied to cell cultures is an effective tool to characterize and compare the modes of action of many substances. We propose this strategy as an asset for upstream selection of the safest nanocarriers in the framework of regulation for nanobiosafety.

The biological fate of nanoparticles (NPs) for biomedical applications is highly dependent of their size and charge, their aggregation state and their surface chemistry. The chemical composition of the NPs surface influences their stability in biological fluids, their interaction with proteins, and their attraction to the cell membranes. In this work, core-shell magnetic mesoporous silica nanoparticles (Fe₃O₄@MSN), that are considered as potential theranostic candidates, are coated with polyethylene glycol (PEG) or 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) lipid bilayer. Their biological fate is studied in comparison to the native NPs. The physicochemical properties of these three types of NPs and their suspension behavior in different media are investigated. The attraction to a membrane model is also evaluated using a supported lipid bilayer. The surface composition of NPs strongly influences their dispersion in biological fluids mimics, protein binding and their interaction with cell membrane. While none of these types of NPs is found to be toxic on mice four days after intravenous injection of a dose of 40 mg kg⁻¹ of NPs, their surface coating nature influences the in vivo biodistribution. Importantly, NP coated with DMPC exhibit a strong accumulation in liver and a very low accumulation in lung in comparison with nude or PEG ones.