DOTAP/UDCA vesicles: novel approach in oligonucleotide delivery

Bile salt-enriched vs. non-enriched nanoparticles: comparison of their physicochemical characteristics and release pattern

Bile salts were first used in the preparation of nanoparticles due to their stabilizing effects. As time went by, they attracted much attention and were increasingly employed in fabricating nanoparticles. It is well accepted that the physicochemical properties of nanoparticles are influential factors in their permeation, distribution, elimination and degree of effectiveness as well as toxicity. The review of articles shows that the use of bile salts in the structure of nanocarriers may cause significant changes in their physicochemical properties. Hence, having information about the effect of bile salts on the properties of nanoparticles could be valuable in the design of optimal carriers. Herein, we review studies in which bile salts were used in preparing liposomes, niosomes and other nanocarriers. Furthermore, the effects of bile salts on entrapment efficiency, particle size, polydispersity index, zeta potential, release profile and stability of nanoparticles are pointed out. Finally, we debate how to take advantage of bile salts potential for preparing desirable nanocarriers.

Nanoplatforms for Targeted Stimuli-Responsive Drug Delivery: A Review of Platform Materials and Stimuli-Responsive Release and Targeting Mechanisms

To achieve the promise of stimuli-responsive drug delivery systems for the treatment of cancer, they should (1) avoid premature clearance; (2) accumulate in tumors and undergo endocytosis by cancer cells; and (3) exhibit appropriate stimuli-responsive release of the payload. It is challenging to address all of these requirements simultaneously. However, the numerous proof-of-concept studies addressing one or more of these requirements reported every year have dramatically expanded the toolbox available for the design of drug delivery systems. This review highlights recent advances in the targeting and stimuli-responsiveness of drug delivery systems. It begins with a discussion of nanocarrier types and an overview of the factors influencing nanocarrier biodistribution. On-demand release strategies and their application to each type of nanocarrier are reviewed, including both endogenous and exogenous stimuli. Recent developments in stimuli-responsive targeting strategies are also discussed. The remaining challenges and prospective solutions in the field are discussed throughout the review, which is intended to assist researchers in overcoming interdisciplinary knowledge barriers and increase the speed of development. This review presents a nanocarrier-based drug delivery systems toolbox that enables the application of techniques across platforms and inspires researchers with interdisciplinary information to boost the development of multifunctional therapeutic nanoplatforms for cancer therapy.

Cationic surfactants derived from lysine: effects of their structure and charge type on antimicrobial and hemolytic activities

Three different sets of cationic surfactants from lysine have been synthesized. The first group consists of three monocatenary surfactants with one lysine as the cationic polar head with one cationic charge. The second consists of three monocatenary surfactants with two amino acids as cationic polar head with two positive charges. Finally, four gemini surfactants were synthesized in which the spacer chain and the number and type of cationic charges have been regulated. The micellization process, antimicrobial activity, and hemolytic activity were evaluated. The critical micelle concentration was dependent only on the hydrophobic character of the molecules. Nevertheless, the antimicrobial and hemolytic activities were related to the structure of the compounds as well as the type of cationic charges. The most active surfactants against the bacteria were those with a cationic charge on the trimethylated amino group, whereas all of these surfactants showed low hemolytic character.

Immunoliposomal systems targeting primary effusion lymphoma: in vitro study

Aims: To develop an appropriate liposomal formulation for gene delivery against primary effusion lymphoma (PEL), a herpesvirus HHV8-associated B-cell lymphoma. Materials & methods: Cationic, cationic PEGylated and cationic PEGylated anti-CD138 liposomes (ILp) linking a monoclonal antibody expressed on PEL cells were prepared by a thin layer evaporation method, followed by extrusion technique. The formulations were mixed with a model oligonucleotide to form the lipoplexes and tested on a BCBL-1 cell (a PEL cell line). The transfection efficiency was evaluated by flow cytometry and confocal laser scanning microscopy analysis. Results: Based on antigen–antibody interaction, ILp mediated a specific gene delivery as shown by a significant increase in the transfection rate and a localized internalization of the oligonucleotide, in comparison with cationic liposomes and cationic PEGylated liposomes. Conclusion: ILp could be proposed as effective carriers for oligonucleotide transfer in BCBL-1 cells. In vitro experimental results encourage us to further test the in vivo therapeutic potential of ILp for specific delivery of antitumoral agents.

Biopolymer-modified graphite oxide nanocomposite films based on benzalkonium chloride-heparin intercalated in graphite oxide

Heparin is a potent anticoagulant agent that interacts strongly with antithrombin III to prevent the formation of fibrin clots. In the present work, poly(dimethylsiloxane)(PDMS)/graphite oxide-benzalkonium chloride-heparin (PDMS/modified graphite oxide) nanocomposite films were obtained by the solution intercalation technique as a possible drug delivery system. The heparin-benzalkonium chloride (BAC-HEP) was intercalated into graphite oxide (GO) layers to form GO-BAC-HEP (modified graphite oxide). Nanocomposite films were characterized by XRD, SEM, TEM, ATR-FTIR and TGA. The modified graphite oxide was observed to be homogeneously dispersed throughout the PDMS matrix. The effect of modified graphite oxide on the mechanical properties of the nanocomposite film was investigated. When the modified graphite oxide content was lower than 0.2 wt%, the nanocomposites showed excellent mechanical properties. Furthermore, nanocomposite films become delivery systems that release heparin slowly to make the nanocomposite films blood compatible. The in vitro studies included hemocompatibility testing for effects on platelet adhesion, platelet activation, plasma recalcification profiles, and hemolysis. Results from these studies showed that the anticoagulation properties of PDMS/GO-BCA-HEP nanocomposite films were greatly superior to those for no treated PDMS. Cell culture assay indicated that PDMS/GO-BCA-HEP nanocomposite films showed enhanced cell adhesion.

Flow cytometry and live confocal analysis for the evaluation of the uptake and intracellular distribution of FITC-ODN into HaCaT cells

In this study, the mechanism of the internalization and the cellular distribution of 59 fluorescein conjugated PS-ODN (FITC-ODN) after transfection with different mixed lipidic vesicles/oligo complexes (lipoplexes) have been investigated. Mixed lipidic vesicles were prepared with one of the most used cationic lipid (DOTAP) and different amounts of a cholic acid (UDCA) to release the oligo into HaCaT cells. Using flow cytometry, the cellular uptake of the oligo was studied with and without different inhibitors able to block selectively the different pathways involved in the internalization mechanism. The intracellular distribution of the oligo was analyzed by confocal laser scanning microscopy (CLSM), treating the cells with the lipoplexes and directly observing without any fixing procedure. To better carry out the colocalization studies, fluorescent-labeled markers, specific for the different cellular compartments, were coincubated with 59 fluorescein-conjugated 29-mer phosphorotioate oligonucleotide (FITC-ODN). The different lipidic vesicles affect the internalization mechanism of FITC-ODN. After using the inhibitors, the uptake of complexes involved a different internalization mechanism. The live CLSM analysis demonstrated that, after 1 hour from the complex incubation, the oligo was transferred into cells and localized into the endosomes; after 24 hours, the oligo was intracellularly localized close to the nuclear structure in a punctuate pattern. However, the results from fusion experiments showed also a binding of a quite low amount of oligo with the cell membranes.

Co-delivery of siRNA and an anticancer drug for treatment of multidrug-resistant cancer

AIMS

To develop a novel nanomedicine approach for the treatment of multidrug-resistant (MDR) cancer by combining an anticancer drug and suppressors of cellular resistance within one multifunctional nanocarrier-based delivery system (NDS).

MATERIALS & METHODS

The NDS consisted of cationic liposomes (carrier, 100-140 nm), doxorubicin (DOX, anticancer drug), siRNA targeted to MRP1 and BCL2 mRNA (suppressors of pump and nonpump cellular-resistance, respectively). The resulting approximately 500 nm complex has a zeta potential of +4 mV.

RESULTS & DISCUSSION

The NDS provides an effective co-delivery of DOX and siRNA as well as cell-death induction and suppression of cellular resistance in MDR lung cancer cells.

CONCLUSION

We demonstrate NDS-enhanced efficiency of chemotherapy to a level that cannot be achieved by applying its components separately.