Persistent luminescence nanoparticles functionalized by polymers bearing phosphonic acid anchors: synthesis, characterization, and in vivo behaviour.

Optical in vivo imaging has become a widely used technique and is still under development for clinical diagnostics and treatment applications. For further development of the field, researchers have put much effort into the development of inorganic nanoparticles (NPs) as imaging probes. In this trend, our laboratory developed ZnGa1.995O4Cr0.005 (ZGO) nanoparticles, which can emit a bright persistent luminescence signal through the tissue transparency window for dozens of minutes and can be activated in vivo with visible irradiation. These properties endow them with unique features, allowing us to recover information over a long-time study with in vivo imaging without any background. To target tissues of interest, ZGO must circulate long enough in the blood stream, a phenomenon which is limited by the mononuclear phagocyte system (MPS). Depending on their size, charge and coating, the NPs are sooner or later opsonized and stored into the main organs of the MPS (liver, spleen, and lungs). The NPs therefore have to be coated with a hydrophilic polymer to avoid this limitation. To this end, a new functionalization method using two different polyethylene glycol phosphonic acid polymers (a linear one, later named lpPEG and a branched one, later named pPEG) has been studied in this article. The coating has been optimized and characterized in various aqueous media. The behaviour of the newly functionalized NPs has been investigated in the presence of plasmatic proteins, and an in vivo biodistribution study has been performed. Among them ZGOpPEG exhibits a long circulation time, corresponding to low protein adsorption, while presenting an effective one-step process in aqueous medium with a low hydrodynamic diameter increase. This new method is much more advantageous than another strategy we reported previously that used a two-step PEG silane coating performed in an organic solvent (dimethylformamide) for which the final hydrodynamic diameter was twice the initial diameter.

Qualitative and quantitative analysis of the uptake of lipoplexes by villous placenta explants.

Controlled distribution of a drug by its association to a nanocarrier is a promising approach for the treatment of pregnancy disorders such as preeclampsia. For this application, tracking both the nanocarrier and the drug is necessary to ensure the safety of both the mother and the foetus. This study reports a method to visualize and quantify the uptake of liposomal formulations in placental tissue using florescent labelling and appropriate analytical tools. Lipoplexes were labelled with a fluorescent lipid, DOPE-NBD while the encapsulated siRNA was fluorescently labelled with rhodamine. Lipoplexes were incubated with villous placenta explants, explants were imaged with confocal microscopy, then DOPE-NBD was extracted from the explant and quantified by HPLC. Qualitative evaluation by confocal microscopy showed the presence of lipoplexes and siRNA into the outer layer of the placental explants, the syncytiotrophoblast. For quantitative evaluation, an HPLC method for the quantification of fluorescent lipid DOPE-NBD in placental tissue was developed and validated. The developed method was applied to quantify the DOPE-NBD uptake in the placental tissue. Increased amounts of DOPE-NBD were detected in placental explants when increasing the incubation concentration of lipoplexes. This study provides a method to evaluate the interactions between liposomal formulation and the placental barrier.

Liposomes as Gene Delivery Vectors for Human Placental Cells.

Nanomedicine as a therapeutic approach for pregnancy-related diseases could offer improved treatments for the mother while avoiding side effects for the fetus. In this study, we evaluated the potential of liposomes as carriers for small interfering RNAs to placental cells. Three neutral formulations carrying rhodamine-labelled siRNAs were evaluated on an in vitro model, i.e., human primary villous cytotrophoblasts. siRNA internalization rate from lipoplexes were compared to the one in the presence of the lipofectamine reagent and assessed by confocal microscopy. Results showed cellular internalization of nucleic acid with all three formulations, based on two cationic lipids, either DMAPAP or CSL-3. Moreover, incubation with DMAPAP+AA provided a rate of labelled cells as high as with lipofectamine (53 ± 15% and 44 ± 12%, respectively) while being more biocompatible. The proportion of cells which internalized siRNA were similar when using DMAPAP/DDSTU (16 ± 5%) and CSL-3 (22 ± 5%). This work highlights that liposomes could be a promising approach for gene therapy dedicated to pregnant patients.

Nanomedicine as a potential approach to empower the new strategies for the treatment of preeclampsia.

Preeclampsia is a serious pregnancy disorder characterized by the onset of high blood pressure and proteinuria. Although the understanding of the disease is increasing, it remains without treatment, other than the delivery of the baby and the placenta. This review sets out to discuss some new developments and strategies in the treatment of preeclampsia. We briefly review the current knowledge on the preeclamptic pathophysiology. We then examine the recent trends in preeclampsia treatment and, in particular, the tracks of potential therapeutic targets. Finally, we focus on the possibilities nanocarriers could offer in the management of preeclampsia. Indeed, nanocarriers could help to prevent transplacental passage and promote placental-specific drug delivery, thereby enhancing efficacy and improving safety. Tendencies are then drawn from the available studies on the optimal characteristics of a nanocarrier to deliver drugs to the placenta.

Assessment of dually labelled PEGylated liposomes transplacental passage and placental penetration using a combination of two ex-vivo human models: the dually perfused placenta and the suspended villous explants.

Uptake and passage of nanocarriers through the placenta are critical information to develop new therapeutic approaches during pregnancy. In order to assess nanocarriers transplacental passage and penetration into the placenta, we studied and optimized two ex-vivo human models: the dually perfused placenta and the placenta explants. Doubly labelled PEGylated liposomes were used as models to provide data on the penetration and transplacental passage of drugs and liposomes. A HPLC method was set-up to quantify both carboxyfluorescein and lipid-rhodamine. Transplacental passage was then quantified using HPLC and placental penetration was assessed using spinning disk microscopy. We found a similar transplacental passage rate for both free and encapsulated carboxyfluorescein as well as a homogeneous fluorescence intensity in the outer cell layer of the placental villous, the syncytiotrophoblast, and the mesenchyma. Besides, liposome-rhodamine was not detected in the fetal circulation. The absence of transplacental passage of PEGylated liposomes is also supported by their detection in the sole syncytiotrophoblast. The combination of two ex-vivo models and the monitoring of both the drug and the carrier provided consistent and complementary information. Overall, we suggest combining the perfused human placenta and the human explants villous models to evaluate nanocarriers designed for treatments during pregnancy.