Dioctadecyldimethylammonium Bromide Research Articles

Co-delivery of siRNA and lycopene encapsulated hybrid lipid nanoparticles for dual silencing of insulin-like growth factor 1 receptor in MCF-7 breast cancer cell line

Insulin-like growth factor-1 receptor (IGF-1R) is expressed in malignant and normal breast tissue, and its intermittent activation by multiple IGF-1 signaling pathways leads to neoplasm cell proliferation, impaired apoptosis, increased survival, and resistance to cytotoxic therapeutic agents. Therefore, simultaneous suppression of the receptor and its cognate ligand would be a powerful promising strategy inhibiting malignant phenotypes of breast cancer cells. In the present study, Methoxypoly(ethylene glycol) - Poly(caprolactone) was hybridized with Dimethyldioctadecylammonium bromide (DDAB) cationic lipid (mPEG-PCL-DDAB) nanoparticles (NPs) and used as a carrier for simultaneous delivery of lycopene and insulin-like growth factor 1 receptor-specific lycopene encapsulated-mPEG-PCL-DDAB nanoparticle/siRNA to MCF-7 breast cancer cells. Then, the antitumor effects of this construct were evaluated in vitro. The results demonstrated that the synthesized mPEG-PCL-DDAB nanoparticle had suitable physicochemical properties. The use of mPEG-PCL-DDAB nanoparticle-loaded anti-insulin-like growth factor 1 receptor-siRNA and lycopene dramatically induced the process of apoptosis and arrested cell cycle in the MCF-7 tumor cell lines. In general, the findings of this study demonstrated the potency of mPEG-PCL-DDAB nanoparticles for dual delivery of siRNA, and lycopene in breast cancer cell lines followed the induction of apoptosis.

Polyoxyethylene Sorbitan Monolaurate induced vesicle-to-micelle transition of aqueous dimethyldioctadecylammonium bromide dispersion

The interactions of micelle forming nonionic surfactant, Polyoxyethylene Sorbitan Monolaurate (Tween 20), with spontaneously formed vesicle dispersions of Dimethyldioctadecylammonium bromide (DDOAB) have been investigated. DDOAB vesicles are solubilized in the Tween 20 micelles and undergo vesicle-to-micelle transition. Differential scanning calorimetry (DSC) measurements show that the addition of Tween 20 lowers the gel-to-liquid crystalline phase transition temperature (Tm) of DDOAB vesicles. The thermogram peak shifts to a lower temperature, broadens and ultimately disappears when the vesicle-to-micelle transition is complete. Fluorescence anisotropy and Turbidity data indicate that the vesicle-to-micelle transition takes place in three stages: the vesicle bilayer is first saturated with Tween 20, the bilayer then disintegrates, and finally a complete solubilization takes place, leading to the formation of mixed micelles. Dynamic light scattering study shows an initial increase of the average vesicle size upon the addition of Tween 20 up to the saturation point and then a decrease upon complete solubilization of vesicles into mixed micelles. The results have been confirmed by observing Transmission Electron Microscopy (TEM). TEM images show evidence of direct transformation of the vesicles to mixed micelles without the formation of intermediate aggregates.

Immunotherapeutic potential of n-terminally formylated ESAT-6 protein in murine tuberculosis.

The early secreted antigenic target-6 kDa (ESAT-6) being one of the important antigens expressed by Mycobacterium tuberculosis (MTB) has been widely investigated for its strong immunmodulatory effects. We have previously evaluated the immunotherapeutic efficacy of ESAT-6 in the murine model of experimental tuberculosis (TB). Now in the present study, we have evaluated the immunotherapeutic efficacy of N-terminally formylated form of ESAT-6 (f-ESAT-6) in murine TB. The production and purification of f-ESAT-6 have been discussed in our earlier report (Mir SA and Sharma S, 2014). In the present study, the MTB H37Rv-infected mice were treated with f-ESAT-6 alone or in combination with anti-TB drugs (ATDs). Four weeks postinitiation of the treatment, the experimental mice were sacrificed, and the colony-forming units (CFUs) were enumerated in their lungs and spleen as described in "materials and methods" section. The N-terminally formylated ESAT-6 protein (f-ESAT-6) induced a moderate reduction in the bacterial load in the target organs of infected mice. Compared to the dimethyldioctadecyl ammonium bromide treated and untreated groups, the f-ESAT-6 treatment significantly reduced the CFU in the spleen and lungs of infected mice by 0.377 log10 units (P < 0.05) and 0.396 log10 units (P < 0.01), respectively. The administration of f-ESAT-6 in combination with ATDs revealed an additional immunotherapeutic effect and elicited higher therapeutic efficacy over drugs (ATDs) alone. The results of the present study clearly indicate that f-ESAT-6 protein alone as well as in combination with the conventional ATDs induce moderate therapeutic effect against experimental TB.

Integrating nanoclay intercalated with interlayers of cationic surfactant into thin-film nanocomposite nanofiltration membranes to improve performance and antifouling property

We fabricated thin-film nanocomposite (TFN) polyamide membrane for the treatment of brine solutions. Different surfactant-modified nanoclay (montmorillonite, MMT) were embedded separately into polyamide layer through interfacial polymerization between piperazine (PIP) and trimesoyl chloride (TMC). These cationic surfactants are: trimethyloctylammonium bromide (OTAB), hexadecyltrimethlammonium bromide (CTAB); and dimethyldioctadecylammonium bromide (DDAB). The cationic surfactants have different chemical structure, which can alter the d-spacing of the nanoclay. The surfactants can also facilitate the dispersion of the nanoclay in TMC/n-hexane solution. Among the surfactants, DDAB has the longest alkane chain on its chemical structure, thus adjusting the d-spacing of the nanoclay at most. TFNDDAB-MMT had the most uniformly dispersed nanoclays on the membrane surface compared to other membranes. The pure water flux of the membranes at 6 bar follows a decreasing order: TFNDDAB-MMT (66.02 ± 5.65 L m−2 h−1) > TFNOTAB-MMT (43.74 ± 3.88 L m−2 h−1) ≈ TFNNa-MMT (45.03 ± 2.80 L m−2 h−1) > TFNCTAB-MMT (41.69 ± 3.00 L m−2 h−1) ≈ TFC (40.93 ± 2.72 L m−2 h−1). Furthermore, it also enhanced the membrane antifouling property with a good stability in wide range of operating condition.

Cationic Nanostructures as Adjuvants for Vaccines.

Spherical or discoidal lipid polymer nanostructures bearing cationic charges successfully adsorb a variety of oppositely charged antigens (Ag) such as proteins, peptides, nucleic acids, or oligonucleotides. This report provides instructions for the preparation and physical characterization of four different cationic nanostructures able to combine and deliver antigens to the immune system: (1) dioctadecyl dimethylammonium bromide (DODAB) bilayer fragments (DODAB BF); (2) polystyrene sulfate (PSS) nanoparticles (NPs) covered with one cationic dioctadecyl dimethylammonium bromide bilayer (DODAB) named (PSS/DODAB); (3) cationic NPs of biocompatible polymer poly(methyl methacrylate) (PMMA) prepared by emulsion polymerization of the methyl methacrylate (MMA) monomer in the presence of DODAB BF (PMMA/DODAB NPs); (4) antigen NPs (NPs) where the cationic polymer poly(diallyl dimethyl ammonium chloride) (PDDA) directly combined at nontoxic and low dose with the antigen (Ag); when the oppositely charged model antigen is ovalbumin (OVA), NPs are named PDDA/OVA. These nanostructures provide adequate microenvironments for carrying and delivering antigens to the antigen-presenting cells of the immune system.

Effective treatment of simulated ASP flooding produced water by modified perlite

Organic perlite (organo-perlite) hybrids were synthesized by ion-exchange interaction of natural perlite with dioctadecyl dimethyl ammonium bromide (DDAB) at different cation exchange capacity (CEC) equivalents of perlite. The morphology and structure of perlite and organo-perlite hybrid products were characterized by WCA, zeta-potential analyzer, SEM, surface area analyzer, FT-IR, QCM-D, AFM, and interfacial rheometer. The surface wettability of perlite was changed from highly hydrophilic to hydrophobic after modification with loaded cationic surfactants, and the inversion of negative to positive charge occurred. It was also found that physical modification of perlite with the cationic surfactant DDAB equivalent to 2.0 CEC of perlite resulted in the preparation of organo-perlite hybrids with better hydrophobicity. Therefore, organo-perlite hybrids at 2.0 CEC equivalent surfactant loading were used to remove emulsified oil from simulated alkali/surfactant/polymer produced water. The experimental results demonstrated that the initial pH, dosage, temperature, and contact time had significant effects on the treatment of oily wastewater. The oil removal efficiency was 99.75% at 60 °C and pH 6. The results indicate that organo-perlite hybrids are highly promising adsorbent materials with broad applications in the fields of oily wastewater treatment and environmental protection.

Lipid exchanges between dioctadecyldimethylammonium bromide monolayer and vesicles in the subphase

AbstractStudies on the interaction of lipid monolayer with bilayer structures, such as vesicles, are relatively scarce in the literature. In order to ascertain whether these structures interact for cationic dioctadecyldimethylammonium bromide (DODAB) monolayers at the aqueous surfaces of 0, 0.05, and 0.5 mmol L−1 DODAB vesicle dispersions, differential scanning calorimetry (DSC) and surface film balance experiments were carried out. DSC results confirmed the presence of unilamellar vesicles in the subphase, while changes in the monolayer surface pressure–area per molecule (π–A) isotherm profile yielded by the presence of DODAB vesicle in the subphase revealed monolayer‐vesicle interactions as a result of monomer exchanges between the monolayer and the vesicles with stronger effects at the higher vesicle concentration investigated.

Cationic and Biocompatible Polymer/Lipid Nanoparticles as Immunoadjuvants.

Nanostructures have been of paramount importance for developing immunoadjuvants. They must be cationic and non-cytotoxic, easily assembling with usually oppositely charged antigens such as proteins, haptens or nucleic acids for use in vaccines. We obtained optimal hybrid nanoparticles (NPs) from the biocompatible polymer poly(methyl methacrylate) (PMMA) and the cationic lipid dioctadecyl dimethyl ammonium bromide (DODAB) by emulsion polymerization of methyl methacrylate (MMA) in the presence of DODAB. NPs adsorbed ovalbumin (OVA) as a model antigen and we determined their adjuvant properties. Interestingly, they elicited high double immune responses of the cellular and humoral types overcoming the poor biocompatibility of DODAB-based adjuvants of the bilayer type. The results suggested that the novel adjuvant would be possibly of use in a variety of vaccines.

Formulations of liposomal vaccine containing AdhO36 antigen and β-glucan as immunoadjuvant

Humans are the most crucial host of Salmonella Typhi as it has limited ability to reproduce outside the human body. Salmonella Typhi infections caused Typhoid fever which can be prevented with vaccines. This study aims to develop an effective typhoid fever oral vaccine using a liposomal delivery system. Several studies showed that the immunization of AdhO36 protein from Salmonella Typhi orally provides significant protection in inhibiting the Salmonella Typhi to the mice intestine. β-Glucan is a potent immunostimulant for macrophages activations. Meanwhile, the method used to produce Liposome formulations was using thin-film hydration. The liposomal products had good characteristics based on their particle size. The particle size results met the requirement for optimum intestinal absorption 399.220 + 28.095 nm Liposome+AdhO36 and 383.360 + 8.594 nm Liposome+β-glucan. Based on the zeta potential measurement, the electrical charges of the three formulations were positive, meaning that the liposome is cationic because of the DDAB (Dimethyl Dioctadecyl Ammonium Bromide) component. The positive charge will facilitate the internalization of antigen to the immunity cells.

Action-potential-inspired osmotic power generation nanochannels

The action potential across biological membranes formed by osmotic gradient induced by external conditions plays a key role in the signal transmission of life processes, which can inspire researchers to develop artificial osmotic power generation device with multi-stimuli controllable power output. Herein, an adaptive 2D nanochannel membrane is fabricated by stacking of montmorillonite nanosheets co-modified with a laboratory synthesized cationic surfactant containing spiropyran species and a commercially cationic surfactant of dioctadecyldimethylammonium bromide. Similar to biological action potentials, the osmotic power generation of 2D nanochannel membranes can be regulated by external multiple stimuli such as light, pH and temperature based on the adaptive ion selectivity and ion flux of nanofluidic channels relying on the surface charges of spiropyran species and the phase state of surfactants. Impressively, the control of temperature rising to 60 °C significantly boosted the maximum power density of 2D nanochannel membrane from ∼0.81 W/m2 to be ∼7.12 W/m2 by 8.8 times at a gradient of artificial sea water and river water resulting from the enhanced ion flux by phase transition of surfactants, which is the highest value among those of clay-based nanochannel membranes and ion exchange membranes. Our results implies that the development of adaptive 2D nanochannel membranes is a new strategy for improving the power output of osmotic energy conversion devices.

Synthesis of methoxy poly(ethylene glycol)-poly(ε-caprolactone) diblock copolymers hybridized with DDAB cationic lipid as the efficient nanocarriers for in vitro delivery of lycopene into MCF-7 breast cancer cells

Given the high rate of cancer mortality in the world, trying to find appropriate therapeutic strategies is a very crucial issue. Since insulin-like growth factor −1(IGF-1) and its receptor (IGF-1R) play a significant role in tumor formation and progression, targeting them can have a vital effect on cancer treatment. Lycopene is a natural antioxidant that exerts its anti-tumor effect by regulating IGF-I signaling and cell cycle arrest, making it a suitable therapeutic agent for reducing tumor induction. However, the utilization of lycopene is limited due to its high lipophilicity and very low solubility in biological body fluids. To overcome this problem, polymer lipid hybrid nanocarriers that have a core-shell structure have received much attention in recent years. In this study, to produce lipid-hybrid nanoparticles (NPs), methoxypolyethylene glycol-polycaprolactone (mPEG-PCL) copolymers were applied for lycopene loading due to biocompatibility, biodegradability, non-toxic nature, small size, amphiphilic properties, and stability of these NPs in the circulatory system. Furthermore, the use of the cationic lipid of Dimethyldioctadecylammonium bromide (DDAB) increased the cellular uptake of nanocarriers. This study proposed mPEG-PCL-DDAB as a potent nanocarrier for drug delivery to MCF-7 breast cancer cell lines, in vitro, and their applicability for the IGF-1R silencing, as a promising anti-cancer therapeutic approach, for the first time.

Effects of sterol derivatives in cationic liposomes onbiodistribution and gene-knockdown in the lungs of mice systemically injected with siRNA lipoplexes.

Cationic liposomes can be intravenously injected to deliver short interfering (si)RNAs into the lungs. The present study investigated the effects of sterol derivatives in systemically injected siRNA/cationic liposome complexes (siRNA lipoplexes) on gene-knockdown in the lungs of mice. Cationic liposomes composed of 1,2-dioleoyl-3-trimethylammonium-propane or dimethyldioctadecylammonium bromide (DDAB) were prepared as a cationic lipid, with sterol derivatives such as cholesterol (Chol), β-sitosterol, ergosterol (Ergo) or stigmasterol as a neutral helper lipid. Transfected liposomal formulations composed of DDAB/Chol or DDAB/Ergo did not suppress the expression of the luciferase gene in LLC-Luc and Colon 26-Luc cells in vitro, whereas other formulations induced moderate gene-silencing. The systemic injection of siRNA lipoplexes formulated with Chol or Ergo into mice resulted in abundant siRNA accumulation in the lungs. In comparison, systemically injected DDAB/Chol or DDAB/Ergo lipoplexes of Tie2 siRNA effectively increased the suppression of the Tie2 mRNA expression in the lungs of mice. These findings indicated that DDAB/Chol and DDAB/Ergo liposomes could function as vectors for siRNA delivery to the lungs.

Development and Evaluation of Solid Witepsol Nanoparticles for Gene Delivery

Gene therapy approaches have become increasingly attractive in the medical, pharmaceutical, and biotechnological industries due to their applicability in the treatment of diseases with no effective conventional therapy. Non-viral delivery using cationic solid lipid nanoparticles (cSLNs) can be useful to introduce large nucleic acids to target cells. A careful selection of components and their amounts is critical to obtain a successful delivery system. In this study, solid Witepsol nanoparticles were formulated, characterized, and evaluated in vitro for gene delivery purposes. Solid Witepsol nanoparticles were formulated through the microemulsion dilution technique using two grades of Witepsol and three surfactants, namely Cremephor RH40, Kolliphor HS15, and Peceol. Dimethyldioctadecylammonium bromide was incorporated into the system as a cationic lipid. Twelve combinations of these ingredients were formulated. The obtained nanoparticles were then evaluated for particle size, zeta potential, DNA binding and protection ability, cytotoxicity, and transfection ability. Particle sizes of the prepared cationic cSLNs were between 13.43±0.06 and 68.80±0.78 nm. Their zeta potential, which is important for DNA binding efficiency, was determined at >+40 mV. Gel retardation assays revealed that the obtained cSLNs can form a compact complex with plasmid DNA (pDNA) encoding green fluorescent protein and that this complex can protect pDNA from DNase I-mediated degradation. Cytotoxicity evaluation of nanoparticles was performed on the L929 cell line. In vitro transfection data revealed that solid Witepsol nanoparticles could effectively transfect fibroblasts. Our findings indicate that solid Witepsol nanoparticles prepared using the microemulsion dilution technique are promising non-viral delivery systems for gene therapy.

Relationship of color change to permeation of target compound in polydiacetylene vesicle system

AbstractPolydiacetylene (PDA) systems, which showed color changes due to the permeation of target molecules, were reported previously by our research group. To use the systems for controlled drug delivery systems, the relationship of the color change to the permeation time of the PDA vesicle must be characterized precisely. Therefore, this relationship was investigated and characterized in this study. Methotrexate (MTX) was used as the target compound and the detection of MTX is an important process in anticancer study. N‐(2‐aminoethyl)pentacosa‐10,12‐diynamide (AEPCDA) was used as the diacetylene surfactant. Dimethyldioctadecylammonium bromide (DOAB) was used as an assistant surfactant. The color change occurred when the mixed surfactant vesicles, with DOAB, were used. When a lower ratio of DOAB was added to the AEPCDA vesicle, the color change rate was slower than that when using the higher ratio of DOAB. The color change rate constants were estimated for several different ratios (AEPCDA:DOAB). Surfactants with different carbon numbers to DOAB were used as the assistant surfactants in this study. The results showed that the color change rate constant decreased with the increasing carbon number of the assistant surfactant. This means that the color change rate can be controlled by changing the assistant surfactant.

Adsorption of protein antigen to the cationic liposome adjuvant CAF®01 is required for induction of Th1 and Th17 responses but not for antibody induction

The degree of antigen adsorption to adjuvants in subunit vaccines may significantly influence the immune responses they induce upon vaccination. Commonly used approaches for studying how the level of adsorption affects the induction of antigen-specific immune responses include (i) using adjuvants with different abilities to adsorb antigens, and (ii) comparing different antigens selected based on their ability to adsorb to the adjuvant. A weakness of these approaches is that not only the antigen adsorption level is varied, but also other important functional factors such as adjuvant composition and/or the B/T cell epitopes, which may affect immunogenicity. Hence, we investigated how changing the adsorption capabilities of a single antigen to an adjuvant influenced the vaccine-induced immune responses. The model antigen lysozyme, which displays a positive net charge at physiological pH due to an isoelectric point (pI) of 11, was succinylated to different extents, resulting in a reduction of the pI value to 4.4–5.9, depending on the degree of succinylation. A pronounced inverse correlation was found between the pI value of the succinylated lysozyme analogues and the degree of adsorption to a cationic liposomal adjuvant consisting of dimethyldioctadecylammonium bromide (DDA) and trehalose dibehenate (TDB) (CAF®01). Furthermore, increased adsorption to this adjuvant correlated directly with the magnitude of lysozyme-specific Th1/Th17 immune responses induced by the vaccine in mice, while there was an inverse correlation with antibody induction. However, high lysozyme-specific antibody titers were induced with an increased antigen dose, even upon vaccination with a strongly adsorbed succinylated lysozyme analogue. Hence, these data illustrate that the degree of lysozyme adsorption to CAF®01 strongly affects the quality of the resulting immune responses.

Antimicrobial and self-crosslinking potential of experimentally developed dioctadecyldimethyl ammonium bromide and riboflavin dentin adhesive.

The aim of the study is to investigate a new formulation, based on dioctadecyldimethyl ammonium-bromide (QA) and riboflavin (RF), combining antimicrobial activities and protease inhibitory properties with collagen crosslinking without interference to bonding capabilities in a rabbit model. Quaternary ammonium riboflavin (QARF) experimental adhesives modified with dioctadecyldimethyl ammonium-bromide and riboflavin were bonded (0.5/1.0/2.0%) to rabbit dentin to investigate for pulpal-histology, interfacial-morphology, transmission electron microscopy, mechanical properties, collagen crosslinking, micro-Raman analysis, antimicrobial, and anti-protease activities. Collagen type-I molecules were generated using molecular-docking. Odontoblasts appeared with normal histology, were seen in controls with no inflammatory cells detected in 0.5% specimens at day 7 and mild inflammatory response at day 30. In QARF 2.0%, inflammatory cells were not detected at day 7 and 30 (p < .05). Dentinal tubules are seen with intact collagen surface in 1% specimens. Resin penetrated inside 1% adhesive specimens with few irregularly funnel-shaped tags. Transmission electron microscopy showed thinner collagen in all specimens except 1% QARF specimens. Biofilms were influenced by QARF adhesives. Elastic moduli were significantly higher in 1.0% and 2.0% QARF adhesive specimens with a significant increase in total crosslinks. Stable amide groups with anti-protease activity was observed in QARF groups. Charged residues were seen in the triple helix hCOL3A1, Gly489-Gly510 after stabilisation with formulation. The 1% QARF modified adhesives improved biochemical and biomechanical properties of rabbit dentin.

Fabrication of Robust Capsules by Sequential Assembly of Polyelectrolytes onto Charged Liposomes.

This work presents a simple methodology for coating small unilamellar liposomes bearing different degrees of positive charge with polyelectrolyte multilayers using the sequential layer-by-layer deposition method. The liposomes were made of mixtures of 1,2-dioleyl-sn-glycero-3-phosphocoline and dimethyl dioctadecyl ammonium bromide (DODAB) and coated by alternated layers of the sodium salt of poly(4-styrenesulfonate) (PSS) and poly(allylamine) (PAH) as polyanions and polycations, respectively. The results show that the zeta potential of the liposomes was not very sensitive to the mole fraction of DODAB in the membrane, XD, in the range 0.3 ≤ XD ≤ 0.8. We were able to coat the liposomes with up to four polymer bilayers. The growth of the capsule size was followed by dynamic light scattering, and in some cases, by cryo-transmission electron microscopy, with good agreement between both techniques. The thickness of the layers, measured from the hydrodynamic radius of the coated liposome, depends on the polyelectrolyte used, so that the PSS layers adopt a much more packaged conformation than the PAH layers. An interesting finding is that the PSS amount needed to reach the isoelectric point of the capsules increases linearly with the charge density of the bare liposomes, whereas the amount of PAH does not depend on it. As expected, the preparation of the multilayers has to be done in such a way that when the system is close to the isoelectric point, the capsules do not aggregate. For this, we dropped the polyelectrolyte solution quickly, stirred it fast, and used dilute liposome suspensions. The method is very flexible and not limited to liposomes or polyelectrolyte multilayers; also, coatings containing charged nanoparticles can be easily made. Once the liposomes have been coated, lipids can be easily eliminated, giving rise to polyelectrolyte nanocapsules (polyelectrosomes) with potential applications as drug delivery platforms.

Oligonucleotide Delivery across the Caco-2 Monolayer: The Design and Evaluation of Self-Emulsifying Drug Delivery Systems (SEDDS).

Oligonucleotides (OND) represent a promising therapeutic approach. However, their instability and low intestinal permeability hamper oral bioavailability. Well-established for oral delivery, self-emulsifying drug delivery systems (SEDDS) can overcome the weakness of other delivery systems such as long-term instability of nanoparticles or complicated formulation processes. Therefore, the present study aims to prepare SEDDS for delivery of a nonspecific fluorescently labeled OND across the intestinal Caco-2 monolayer. The hydrophobic ion pairing of an OND and a cationic lipid served as an effective hydrophobization method using either dimethyldioctadecylammonium bromide (DDAB) or 1,2-dioleoyl-3-trimethylammonium propane (DOTAP). This strategy allowed a successful loading of OND-cationic lipid complexes into both negatively charged and neutral SEDDS. Subjecting both complex-loaded SEDDS to a nuclease, the negatively charged SEDDS protected about 16% of the complexed OND in contrast to 58% protected by its neutral counterpart. Furthermore, both SEDDS containing permeation-enhancing excipients facilitated delivery of OND across the intestinal Caco-2 cell monolayer. The negatively charged SEDDS showed a more stable permeability profile over 120 min, with a permeability of about 2 × 10−7 cm/s, unlike neutral SEDDS, which displayed an increasing permeability reaching up to 7 × 10−7 cm/s. In conclusion, these novel SEDDS-based formulations provide a promising tool for OND protection and delivery across the Caco-2 cell monolayer.

Phase Change Dimethyldioctadecylammonium-Shelled Microdroplets as a Promising Drug Delivery System: Results on 3D Spheroids of Mammalian Tumor Cells.

Significant improvement of phase-change perfluorocarbon microdroplets (MDs) in the vast theranostic scenario passes through the optimization of the MDs composition with respect to synthesis efficiency, stability, and drug delivery capability. To this aim, decafluoropentane (DFP) MDs stabilized by a shell of dimethyldioctadecylammonium bromide (DDAB) cationic surfactant were designed. A high concentration of DDAB-MDs was readily obtained within a few seconds by pulsed high-power insonation, resulting in low polydisperse 1 µm size droplets. Highly positive ζ-potential, together with a long, saturated hydrocarbon chains of the DDAB shell, are key factors to stabilize the droplet and the drug cargo therein. The high affinity of the DDAB shell with cell plasma membrane allows for localized chemotherapeutics delivery by increasing the drug concentration at the tumor cell interface and boosting the uptake. This would turn DDAB-MDs into a relevant drug delivery tool exhibiting high antitumor activity at very low drug doses. In this work, the efficacy of such an approach is shown to dramatically improve the effect of doxorubicin against 3D spheroids of mammalian tumor cells, MDA-MB-231. The use ofthree-dimensional (3D) cell cultures developed in the form of multicellular tumor spheroids (i.e., densely packed cells in a spherical shape) has numerous advantages compared to 2D cell cultures: in addition to have the potential to bridge the gap between conventional in vitro studies and animal testing, it will improve the ability to perform more predictive in vitro screening assays for preclinical drug development or evaluate the potential of off-label drugs and new co-targeting strategies.

Advax adjuvant formulations promote protective immunity against aerosol Mycobacterium tuberculosis in the absence of deleterious inflammation and reactogenicity

The development of safe and effective adjuvants is a critical goal of vaccine development programs. In this report, we defined the immunostimulatory profile and protective effect against aerosol Mycobacterium tuberculosis infection of vaccine formulations incorporating the semi-crystalline adjuvant δ-inulin (Advax). Advax formulated with CpG oligonucleotide and the QS-21 saponin (AdvaxCpQS) was the most effective combination, demonstrated by the capacity of CysVac2/AdvaxCpQS to significantly reduce the bacterial burden in the lungs of M. tuberculosis-infected mice. CysVac2/AdvaxCpQS protection was associated with rapid influx of neutrophils, macrophages and monocytes to the site of vaccination and the induction of antigen-specific IFN-γ+/IL-2+/TNF+ polyfunctional CD4+ T cells in the lung. When compared to the highly potent adjuvant combination of monophosphoryl lipid A and dimethyldioctadecylammonium bromide (MPL/DDA), AdvaxCpQS imparted a similar level of protective efficacy yet without the profound stimulation of inflammatory cytokines and vaccination site ulceration observed with MPL/DDA. Addition of DDA to CysVac2/AdvaxCpQS further improved the protective effect of the vaccine, which correlated with increased polyfunctional CD4+ T cells in the lung but with no increase in vaccine reactogenicity. The data demonstrate that Advax formulations can decouple protective tuberculosis immunity from reactogenicity, making them ideal candidates for human application.