Search

Microfluidization has been investigated as a new, scalable, and basic component saving method to produce cationic lipid nanoparticles, in particular for the delivery of short interfering RNAs (siRNAs). The design of experiment (DoE) allowed to reach optimized characteristics in terms of nanocarrier size reduction and low polydispersity. The structure of cationic liposomes and siRNA-lipoplexes was characterized. The optimized preparation parameters were identified as three microfluidization passages at a pressure of 10,000 psi, with a thin film hydration volume of 4 ml. Microfluidized liposomes mean size was 160 nm, with a polydispersity index of 0.2-0.3 and a zeta potential of +40 mV to +60 mV. Positive versus negative charge ratio between the charges of the cationic lipid and the phosphate charges of the siRNAs is a key factor determining the structure and silencing efficacy of siRNA lipoplexes. At a (+/-) charge ratio of 8, a proportion of 88% of the siRNA was associated to microfluidized lipoplexes, which remained stable for one month. These lipoplexes exhibited moderate cytotoxicity and gene silencing efficacy, which should be further optimized., (Copyright © 2021 Elsevier B.V. All rights reserved.)

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., (Copyright © 2019 Elsevier B.V. All rights reserved.)

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., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Among drug delivery systems, catanionic vesicles now appear as powerful candidates for pharmaceutical applications because they are relatively cheap and easy to use, thus well corresponding to industrial requirements. Using labelled vesicles made of a tricatenar catanionic surfactant, the work reported here aims at exploring the mechanisms by which internalisation into a cell occurs. The study was performed on various cell types such as phagocytic as well as non-phagocytic cells using confocal laser scanning microscopy and flow cytometry. Using various inhibitors, endocytosis and also a passive process, as probably fusion, were highlighted as interaction phenomena between catanionic vesicles and cell membranes. Finally, the interaction modelled with giant liposomes as membrane models confirmed the hypothesis of the occurrence of a fusion phenomenon between the nanovectors and cell membranes. This process highlights the potential of catanionic vesicles for a future pharmaceutical application as a universal drug delivery system., (Copyright © 2010 Elsevier B.V. All rights reserved.)