Phospholipid Liposomes Research Articles

Membrane-Disrupting Activity of Cobra Cytotoxins Is Determined by Configuration of the N-Terminal Loop

In aqueous solutions, cobra cytotoxins (CTX), three-finger folded proteins, exhibit conformational equilibrium between conformers with either cis or trans peptide bonds in the N-terminal loop (loop-I). The equilibrium is shifted to the cis form in toxins with a pair of adjacent Pro residues in this loop. It is known that CTX with a single Pro residue in loop-I and a cis peptide bond do not interact with lipid membranes. Thus, if a cis peptide bond is present in loop-I, as in a Pro-Pro containing CTX, this should weaken its lipid interactions and likely cytotoxic activities. To test this, we have isolated seven CTX from Naja naja and N. haje cobra venoms. Antibacterial and cytotoxic activities of these CTX, as well as their capability to induce calcein leakage from phospholipid liposomes, were evaluated. We have found that CTX with a Pro-Pro peptide bond indeed exhibit attenuated membrane-perturbing activity in model membranes and lower cytotoxic/antibacterial activity compared to their counterparts with a single Pro residue in loop-I.

Preparation and properties of fucoxanthin-loaded liposomes stabilized by sea cucumber derived cholesterol sulfate instead of cholesterol

The preparation of steady-state phospholipid liposomes requires cholesterol as a stabilizer, but excessive intake of cholesterol may increase the risk of cardiovascular disease. The sulfated sterols extracted from sea cucumber, mainly including sulfated 24-methylene cholesterol and cholesterol sulfate, have been reported to have a variety of physiological activities. Sulfated sterols are similar to cholesterol in structure and have the potential to replace cholesterol to prepare novel stable multifunctional liposomes, allowing the liposomes to act as carriers for the delivery of less bioavailable nutrients while allowing sulfated sterols in the lipid bilayer to exert physiologically active effects. This study aimed to prepare a novel multifunctional nanoliposome stabilized with sulfated sterols from sea cucumber instead of cholesterol by ultrasound-assisted thin-film dispersion method. The results showed that stable and uniformly dispersed nanoliposomes could be formed when the substitution ratio of sea cucumber-derived cholesterol sulfate was 100% and the ratio of lecithin to cholesterol sulfate was 3:1. Fucoxanthin encapsulated liposome with egg yolk lecithin/sea cucumber-derived cholesterol sulfate/fucoxanthin mass ratio of 6:2:3 was successfully prepared, with an average particle size of 214 ± 3nm, polydispersity index (PDI) value of 0.297 ± 0.006, the zeta potential of-57.2 ± 1.10mV, and the encapsulation efficiency of 85.5 ± 0.8%. The results of digestion and absorption invitro and invivo showed that liposomes could significantly improve the bioavailability of fucoxanthin and prolong its residence time in serum. As an efficient multifunctional carrier, this novel liposome has great potential for applications in functional foods and biomedicine.

Drug Stability and Minimized Acid-/Drug-Catalyzed Phospholipid Degradation in Liposomal Irinotecan

Therapeutics at or close to the nanoscale, such as liposomal irinotecan, offer significant promise for the treatment of solid tumors. Their potential advantage over the unencapsulated or free form of the drug is due in part to their altered biodistribution. For slow and sustained release, significant optimization of formulation is needed to achieve the required level of stability and allow long-term storage of the drug product. Gradient-based liposomal formulation of camptothecins such as irinotecan poses unique challenges owing to the camptothecin- and acid-catalyzed hydrolysis of phospholipid esters in the inner monolayer of the liposomal membrane. We demonstrated that a narrow set of conditions related to the external pH, temperature, intraliposomal concentration, identity of the drug-trapping agent, physical form of the drug inside the liposomes, and final drug load have a marked impact on the stability of the liposome phospholipid membrane. The physical form of the drug inside the liposome was shown to be an insoluble gel with an irinotecan-to-sulfate ratio approximating 1:1, reducing the potential for irinotecan-catalyzed phospholipid hydrolysis in the internal phospholipid monolayer. As a result of this work, a stable and active liposome formulation has been developed that maintains phospholipid chemical stability following long-term storage at 2-8°C.

Comparison of two methods for tumour-targeting peptide modification of liposomes.

Liposomes decorated with tumour-targeting cell-penetrating peptides can enhance specific drug delivery at the tumour site. The TR peptide, c(RGDfK)-AGYLLGHINLHHLAHL(Aib)HHIL, is pH-sensitive and actively targets tumour cells that overexpress integrin receptor αvβ3, such as B16F10 melanoma cells. Liposomes can be modified with the TR peptide by two different methods: utilization of the cysteine residue on TR to link DSPE-PEG2000-Mal contained in the liposome formula (LIPTR) or decoration of TR with a C18 stearyl chain (C18-TR) for direct insertion into the liposomal phospholipid bilayer through electrostatic and hydrophobic interactions (LIPC18-TR). We found that both TR and C18-TR effectively reversed the surface charge of the liposomes when the systems encountered the low pH of the tumour microenvironment, but LIPC18-TR exhibited a greater increase in the charge, which led to higher cellular uptake efficiency. Correspondingly, the IC50 values of PTX-LIPTR and PTX-LIPC18-TR in B16F10 cells in vitro were 2.1-fold and 2.5-fold lower than that of the unmodified PTX-loaded liposomes (PTX-LIP), respectively, in an acidic microenvironment (pH 6.3). In B16F10 tumour-bearing mice, intravenous administration of PTX-LIPTR and PTX-LIPC18-TR (8 mg/kg PTX every other day for a total of 4 injections) caused tumour reduction ratios of 39.4% and 56.1%, respectively, compared to 20.8% after PTX-LIP administration. Thus, we demonstrated that TR peptide modification could improve the antitumour efficiency of liposomal delivery systems, with C18-TR presenting significantly better results. After investigating different modification methods, our data show that selecting an adequate method is vital even when the same molecule is used for decoration.

Immune checkpoint blockade enhances chemophototherapy in a syngeneic pancreatic tumor model.

Pancreatic cancer (PaCa) suffers from poor treatment options for locally advanced cases. Chemophototherapy (CPT) is an emerging anti-tumor modality, and porphyrin–phospholipid liposomes have been shown to be versatile drug carriers for CPT in preclinical rodent models. Here we show that in the syngeneic subcutaneous KPC PaCa tumor model, exhausted CD8+ T cells are localized in the tumor, and that CPT is enhanced in combination with immune checkpoint blockade (ICB). Addition of ICB using anti-programmed cell death 1 (PD-1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) antibodies resulted in ablation of medium-sized, established KPC tumors (∼200 mm3) without recurrence for over 100 days. Mice rejected subsequent tumor re-challenge. Flow cytometry and tumor slice analysis following injection of a fluorescently labeled anti-PD-1 antibody showed that CPT improved antibody delivery to the tumor microenvironment. Treatment of large established tumors (∼400 mm3) using with CPT and ICB induced appreciable tumor regression and delay in regrowth. Taken together, these data demonstrate the utility of combining CPT with immunotherapies.

Hepatocyte Rap1a contributes to obesity- and statin-associated hyperglycemia.

SUMMARYExcessive hepatic glucose production contributes to the development of hyperglycemia and is a key feature of type 2 diabetes. Here, we report that activation of hepatocyte Rap1a suppresses gluconeogenic gene expression and glucose production, whereas Rap1a silencing stimulates them. Rap1a activation is suppressed in obese mouse liver, and restoring its activity improves glucose intolerance. As Rap1a′s membrane localization and activation depends on its geranylgeranylation, which is inhibited by statins, we show that statin-treated hepatocytes and the human liver have lower active-Rap1a levels. Similar to Rap1a inhibition, statins stimulate hepatic gluconeogenesis and increase fasting blood glucose in obese mice. Geranylgeraniol treatment, which acts as the precursor for geranylgeranyl isoprenoids, restores Rap1a activity and improves statin-mediated glucose intolerance. Mechanistically, Rap1a activation induces actin polymerization, which suppresses gluconeogenesis by Akt-mediated FoxO1 inhibition. Thus, Rap1a regulates hepatic glucose homeostasis, and blocking its activity, via lowering geranylgeranyl isoprenoids, contributes to statin-induced glucose intolerance.

DEVELOPMENT OF CATHELICIDIN IN LIPOSOME CARRIER USING THIN LAYER HYDRATION METHOD

Objective: The purpose of this study was to produce an optimum liposome formulation and to study the effect of formulation parameter such as phospholipid amount and hydration time on characteristics of liposome containing Cathelichidin. Methods: Liposomes were prepared using a thin layer hydration method. Characterization of liposomes included organoleptic, PSA (Particle Size Analyzer) and zeta potential, entrapment efficiency, morphology by TEM (Transmission Electron Microscopy), the chemical interaction by FTIR (Fourier Transform Infrared Spectroscopy), and the stability by using Freeze-Thaw method. Results: The result of the organoleptic test showed that the liposome were in the form of milky white dispersion, odorless, and without sedimentation. Optimum formula was obtained by making variations of soy oil: cholesterol 10: 0 (F1), 9: 1 (F2), 8: 2 (F3), 7: 3 (F4), and variations in sonication time (10 and 30 min). Based on the results, it was found that the optimum sonication time was 30 min. F2 and F3 were chosen as the most optimum formulas with particle sizes of 190.3±6.8 nm and 212.9±4.4 nm; polydispersity index of 0.192±0.023 and 0.137±0.022, and zeta potential as much as-38.8±0.6 mV and-34.8±2.0 mV. To the optimum formula, cathelicidin was loaded with hydration time varies of 100 and 120 min. Longer hydration time resulted in smaller particle size and higher entrapment efficiency either for F2 or F3. TEM characterization revealed a spherical shape of liposomes from the optimum formula. The results of FTIR characterization did not show any interaction between the phospholipids of liposomes with cathelicidin. The data from the stability test showed good stability for F2 and F3 with a hydration time of 120 min, indicated by a p-value>0.05, which indicated that there was no significant change in the zeta potential for three Freeze-Thaw cycles. Conclusion: Formula of liposom using a variation of soy oil: cholesterol 9:1 and 8:2 with hydration time of 120 min revealed the best result with good stability for three Freeze-Thaw cycles.

Optimal combination of cationic lipid and phospholipid in cationic liposomes for gene knockdown in breast cancer cells and mouse lung using siRNA lipoplexes.

Formulation of cationic liposomes is a key factor that determine the gene knockdown efficiency by cationic liposomes/siRNA complexes (siRNA lipoplexes). Here, to determine the optimal combination of cationic lipid and phospholipid in cationic liposomes for in vitro and in vivo gene knockdown using siRNA lipoplexes, three types of cationic lipid were used, namely 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP), dimethyldioctadecylammonium bromide (DDAB) and 11-[(1,3-bis(dodecanoyloxy)-2-((dodecanoyloxy)methyl)propan-2-yl)amino]-N,N,N-trimethyl-11-oxoundecan-1-aminium bromide (TC-1-12). Thereafter, 30 types of cationic liposome composed of each cationic lipid with phosphatidylcholine or phosphatidylethanolamine containing saturated or unsaturated dialkyl chains (C14, C16, or C18) were prepared. The inclusion of phosphatidylethanolamine containing unsaturated and long dialkyl chains with DOTAP- or DDAB-based cationic liposomes induced strong luciferase gene knockdown in human breast cancer MCF-7-Luc cells stably expressing luciferase gene. Furthermore, the inclusion of phosphatidylcholine or phosphatidylethanolamine containing saturated and short dialkyl chains or unsaturated and long dialkyl chains into TC-1-12-based cationic liposomes resulted in high gene knockdown efficacy. When cationic liposomes composed of DDAB/1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), TC-1-12/DOPE and TC-1-12/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine were used, significant gene knockdown occurred in the lungs of mice following systemic injection of siRNA lipoplexes. Overall, the present findings indicated that optimal phospholipids in cationic liposome for in vitro and in vivo siRNA transfection were affected by the types of cationic lipid used.

Polyvinylpyrrolidone-Modified Taxifolin Liposomes Promote Liver Repair by Modulating Autophagy to Inhibit Activation of the TLR4/NF-κB Signaling Pathway.

Taxifolin (TAX) is a hepatoprotective flavanol compound, which is severely limited by poor solubility and low bioavailability. Liposomes (Lips) are used as well-recognized drug carrier systems that improve the water solubility and bioavailability of drugs, but are easily damaged by gastric juice after oral administration, resulting in the release of drugs in the gastric juice. Therefore, it is important to find materials that modify liposomes and avoid the destruction of the liposomal phospholipid bilayer structure by the gastrointestinal environment. Taxifolin liposomes (TAX-Lips) were modified by polyvinylpyrrolidone-k30 (PVP-TAX-Lips) and manufactured using a thin-film hydration technique. Particle size (109.27 ± 0.50 nm), zeta potential (−51.12 ± 3.79 mV), polydispersity coefficient (PDI) (0.189 ± 0.007), and EE (84.7 ± 0.2%) of PVP-TAX-Lips were studied. In addition, the results of in vitro release experiments indicated that the cumulative release rates of TAX-Lips and PVP-TAX-Lips were 89.73 ± 5.18% and 65.66 ± 4.86% in the simulated gastric fluid after 24 h, respectively, while the cumulative release rates were 68.20 ± 4.98% and 55.66 ± 3.92% in the simulated intestinal fluid after 24 h, respectively. Moreover, PVP-TAX-Lips were able to reverse lipopolysaccharide and D-galactosamine (LPS/D-GalN)-induced acute liver injury (ALI) by inducing autophagy to inhibit the expression levels of the TLR4/NF-κB signaling pathway and inflammatory factors, which suggested that PVP-TAX-Lips played an important role in the prevention of ALI and also provided a promising drug delivery system for the application of TAX.

Single Molecule-Level Detection via Liposome-Based Signal Amplification Mass Spectrometry Counting Assay.

Because of the low atomization and/or ionization efficiencies of many biological macromolecules, the application of mass spectrometry to the direct quantitative detection of low-abundance proteins and nucleic acids remains a significant challenge. Herein, we report mass spectrum tags (MS-tags) based upon gold nanoparticle (AuNP)-templated phosphatidylcholine phospholipid (DSPC) liposomes, which exhibit high and reliable signals via electrospray ionization (ESI). Using these MS-tags, we constructed a liposome signal amplification-based mass spectrometric (LSAMS) "digital" counting assay to enable ultrasensitive detection of target nucleic acids. The LSAMS system consists of liposomes modified with a gold nanoparticle core and surface-anchored photocleavable DNA. In the presence of target nucleic acids, the modified liposome and a magnetic bead simultaneously hybridize with the target nucleic acid. After magnetic separation and photolysis, the MS-tag is released and can be analyzed by ESI-MS. At very low target concentrations, one liposome particle corresponds to one target molecule; thus, the concentration of the target can be estimated by counting the number of liposomes. With this assay, hepatitis C (HCV) virus RNA was successfully analyzed in clinical samples.

Photoacoustic Effect of Near-Infrared Absorbing Organic Molecules via Click Chemistry.

Near-infrared dyes were developed to be contrast agents due to their ability to improve the productivity of photoacoustic (PA) imaging and photothermal therapy (PTT) treatments. During the article, we described in detail the PA and PT effects of a category of organic molecules. F4-TCNQ could potentially cause a red-shift in the peak PA intensity. The results show that the PTT intensity of the near-infrared dyes with phenyl groups were higher than near-infrared dyes with thiophene groups. We also investigated the photodynamic treatment effect of C1b to demonstrate that these dyes are highly desirable in biochemistry. The high photoacoustic intensity of the organic molecules and the good yield of reactive oxygen species could indicate that these dyes have good potential for a wide range of imaging applications. Finally, we embedded the dye (C1b) in a liposomal hydrophobic phospholipid bilayer (C1b⊂L) to facilitate the application of hydrophobic dyes in biomedical applications, which can be absorbed by cells with good compatible and high stability for the imaging of cellular PA.

Membrane Interactivity of Capsaicin Antagonized by Capsazepine.

Although the pharmacological activity of capsaicin has been explained by its specific binding to transient receptor potential vanilloid type 1, the amphiphilic structure of capsaicin may enable it to act on lipid bilayers. From a mechanistic point of view, we investigated whether capsaicin and its antagonist capsazepine interact with biomimetic membranes, and how capsazepine influences the membrane effect of capsaicin. Liposomal phospholipid membranes and neuro-mimetic membranes were prepared with 1,2-dipalmitoylphosphatidylcholine and with 1-palmitoyl-2-oleoylphosphatidylcholine and sphingomyelin plus cholesterol, respectively. These membrane preparations were subjected to reactions with capsaicin and capsazepine at 0.5–250 μM, followed by measuring fluorescence polarization to determine the membrane interactivity to modify the fluidity of membranes. Both compounds acted on 1,2-dipalmitoylphosphatidylcholine bilayers and changed membrane fluidity. Capsaicin concentration-dependently interacted with neuro-mimetic membranes to increase their fluidity at low micromolar concentrations, whereas capsazepine inversely decreased the membrane fluidity. When used in combination, capsazepine inhibited the effect of capsaicin on neuro-mimetic membranes. In addition to the direct action on transmembrane ion channels, capsaicin and capsazepine share membrane interactivity, but capsazepine is likely to competitively antagonize capsaicin’s interaction with neuro-mimetic membranes at pharmacokinetically-relevant concentrations. The structure-specific membrane interactivity may be partly responsible for the analgesic effect of capsaicin.

A modified thin film method for large scale production of dimeric artesunate phospholipid liposomes and comparison with conventional approaches

Dimeric artesunate phospholipid (ART-GPC), an amphiphilic derivative of artemisinin dimer reported in our previous work, can be applied to treat malaria effectively. The objective of this study is to develop a facile method for the industrial production of ART-GPC liposomes. Conventional methods including thin film hydration (TFH), ethanol injection (EI), and freeze drying (FD) were used to prepare ART-GPC liposomes, and the resultants presented poor physicochemical properties. Fortunately, a modified thin film hydration method (MTFH) by forming thin film of ART-GPC composed of fine lipid bilayer structure in the vials showed promise for the liposomes production. A quality design strategy (solvents, pressure, hydration time, and temperature) was performed to obtain optimal physicochemical characteristics and production conditions. Thereafter, ART-GPC liposomes are produced under GMP conditions with the size of 176.32 nm, PDI of 0.17, zeta potential of −25.79 mV, and osmotic pressure of 297.33 mOsm/kg, confirming the scalability and reproductivity of the MTFH technology. It is the first report that the MTFH method allows liposomes to be preserved in a dry film state and in-situ hydrated in injection vials with excellent performance. Conclusively, the MTFH method is a promising technology for the large-scale production of ART-GPC liposomes.

Membrane Phase Drives the Assembly of Gold Nanoparticles on Biomimetic Lipid Bilayers.

In recent years, many efforts have been devoted to investigating the interaction of nanoparticles (NPs) with lipid biomimetic interfaces, both from a fundamental perspective aimed at understanding relevant phenomena occurring at the nanobio interface and from an application standpoint for the design of novel lipid–nanoparticle hybrid materials. In this area, recent reports have revealed that citrate-capped gold nanoparticles (AuNPs) spontaneously associate with synthetic phospholipid liposomes and, in some cases, self-assemble on the lipid bilayer. However, the mechanistic and kinetic aspects of this phenomenon are not yet completely understood. In this study, we address the kinetics of interaction of citrate-capped AuNP with lipid vesicles of different rigidities (gel-phase rigid membranes on one side and liquid-crystalline-phase soft membranes on the other). The formation of AuNP–lipid vesicle hybrids was monitored over different time and length scales, combining experiments and simulation. The very first AuNP–membrane contact was addressed through molecular dynamics simulations, while the structure, morphology, and physicochemical features of the final colloidal objects were studied through UV–visible spectroscopy, small-angle X-ray scattering, dynamic light scattering, and cryogenic electron microscopy. Our results highlight that the physical state of the membrane triggers a series of events at the colloidal length scale, which regulate the final morphology of the AuNP–lipid vesicle adducts. For lipid vesicles with soft membranes, the hybrids appear as single vesicles decorated by AuNPs, while more rigid membranes lead to flocculation with AuNPs acting as bridges between vesicles. Overall, these results contribute to a mechanistic understanding of the adhesion or self-assembly of AuNPs onto biomimetic membranes, which is relevant for phenomena occurring at the nano–bio interfaces and provide design principles to control the morphology of lipid vesicle–inorganic NP hybrid systems.

Add-on phospholipid liposomes in a postmenopausal depressive episode of a patient with major depressive disorder

Add-on phospholipid liposomes in a postmenopausal depressive episode of a patient with major depressive disorder

Hollow spherical nucleic acid structures based on polymer-coated phospholipid vesicles.

A feasible one pot synthesis of hollow spherical nucleic acids (SNAs) using phospholipid liposomes is reported. These constructs are synthesized in a chemically straightforward process involving formation of unilamellar liposomes, coating the liposomes with a thin cross-linked polymeric layer, and grafting the latter with short (about 20 bases) DNA oligonucleotide strands. They consist of vesicular cores, composed of readily available phospholipid (1,2-dipalmitoyl-sn-glycero-phosphocholine), whereas the strands are deliberately arranged on the surface of the vesicular entities. The initial vesicular structure and morphology are preserved during the coating and grafting reactions. The novel hollow/vesicular SNAs are characterized with a hydrodynamic radius and radius of gyration of 78.3 and 88.5 nm, respectively, and moderately negative (-14.2 mV) ζ potential. They carry thousands (5868) of oligonucleotide strands per vesicle, which are not strongly radially oriented and adopt an unextended conformation as anticipated from the smaller value of the grafting density compared to the critical grafting density at the transition to brush conformation. The constructs are practically devoid of toxicity and exhibit high binding affinity to complementary nucleic acids. Unlike any other nucleic acid structural motif, they cross the cell membrane and enter cells without the need of transfection agents.

Inhibition of cryoaggregation of phospholipid liposomes by an Arabidopsis intrinsically disordered dehydrin and its K-segment

Dehydrin is an intrinsically disordered protein involved in the cold tolerance of plants. Although dehydrins have been thought to protect biomembranes under cold conditions, the underlying protective mechanism has not been confirmed. Here we report that Arabidopsis dehydrin AtHIRD11 inhibited the aggregation of phospholipid liposomes after freezing and thawing. AtHIRD11 showed significantly greater cryoaggregation-prevention activity than cryoprotective agents such as trehalose, proline, and polyethylene glycols. Amino acid sequence segmentation analysis indicated that the K-segment of AtHIRD11 inhibited the cryoaggregation of phosphatidylcholine (PC) liposomes but other segments did not. This showed that K-segments conserved in all dehydrins were likely to be the cryoprotective sites of dehydrins. Amino acid replacement for a typical K-segment (TypK for short) sequence demonstrated that both hydrophobic and charged amino acids were required for the cryoaggregation-prevention activity of PC liposomes. The amino acid shuffling of TypK remarkably reduced cryoprotective activity. Although TypK did not bind to PC liposomes in solution, the addition of liposomes reduced its disordered content under crowded conditions. Together, these results suggested that dehydrins protected biomembranes via conserved K-segments whose sequences were optimized for cryoprotective activities.

Tyrosine kinase inhibitor prodrug-loaded liposomes for controlled release at tumor microenvironment

Tyrosine kinase inhibitors (TKIs) represent one of the most advanced class of therapeutics for cancer treatment. Most of them are also cytochrome P450 (CYP) inhibitors and/or substrates thereof. Accordingly, their efficacy and/or toxicity can be affected by CYP-mediated metabolism and by metabolism-derived drug-drug interactions. In order to enhance the therapeutic performance of these drugs, we developed a prodrug (Pro962) of our TKI TK962 specifically designed for liposome loading and pH-controlled release in the tumor. A cholesterol moiety was linked to TK962 through pH-sensitive hydrazone bond for anchoring to the liposome phospholipid bilayer to prevent leakage of the prodrug from the nanocarrier. Bioactivity studies performed on isolated target kinases showed that the prodrug maintains only partial activity against them and the release of TK962 is required. Biopharmaceutical studies carried out with prodrug loaded liposomes showed that the prodrug was firmly associated with the vesicles and the drug release was prevented under blood-mimicking conditions. Conversely, conventional liposome loaded with TK962 readily released the drug. Flow cytometric studies showed that liposomes efficiently provided for intracellular prodrug delivery. The use of the hydrazone linker yielded a pH-controlled drug release, which resulted in about 50% drug release at pH 4 and 5 in 2 h. Prodrug, prodrug loaded liposomes and active lead compound have been tested against cancer cell lines in either 2D or 3D models. The liposome formulation showed higher cytotoxicity than the unformulated lead TK962 in both 2D and 3D models. The stability of prodrug, prodrug loaded liposomes and active lead compound in human serum and against human, mouse, and rat microsomes was also assessed, demonstrating that liposome formulations impair the metabolic reactions and protect the loaded compounds from catabolism. The results suggest that the liposomal formulation of pH releasable TKI prodrugs is a promising strategy to improve the metabolic stability, intracellular cancer cell delivery and release, and in turn the efficacy of this class of anticancer drugs.

INRA96 Supplemented With Phospholipids Liposomes, A Promising Approach for Stallion Sperm Chilling

Among biotechnologies of reproduction in the equine species, artificial insemination remains the most used technology especially for cooled transported sperm. Although the use of INRA96 extender has demonstrated its efficiency for long-term sperm storage at 4°C or 15°C, some stallions (“bad coolers”) are excluded from such technology.Some years ago, we demonstrated that liposomes produced from egg yolk (EY) phospholipids could be an alternative to egg yolk plasma in stallion freezing extenders. To develop a new extender for sperm chilling, we evaluated the protective effect of liposomes produced from EY phospholipids on stallion sperm storage at 4°C.The sperm of stallions from two studs was diluted in INRA96 extender (as control) or an experimental extender (EE) composed of INRA96 supplemented with liposomes of EY phospholipids. After 24H (D1), 72H (D3), and 6 days (D6) or 7 days (D7), motility parameters were evaluated using Computer Assisted Semen Analyzer.Our results demonstrated that total and progressive motility decreased significantly after dilution and storage in INRA96 between D1 and D3 (P < .05) while no significant decrease was observed between D1 and D3 with EE. Regarding VAP parameter, no significant difference was observed between extenders except at D7 in stud 2.Moreover, total and progressive motility were maintained at a significantly higher level (D3, D6, D7) when sperm was stored in EE compared to INRA96.These promising results demonstrate that the supplementation of INRA96 extender with egg-yolk phospholipids liposomes allows a higher protection to stallion sperm cells.

Easy Preparation of Liposome@PDA Microspheres for Fast and Highly Efficient Removal of Methylene Blue from Water.

Mussel-inspired chemistry was usefully exploited here with the aim of developing a high-efficiency, environmentally friendly material for water remediation. A micro-structured material based on polydopamine (PDA) was obtained by using liposomes as templating agents and was used for the first time as an adsorbent material for the removal of methylene blue (MB) dye from aqueous solutions. Phospholipid liposomes were made by extrusion and coated with PDA by self-polymerization of dopamine under simple and mild conditions. The obtained Liposome@PDA microspheres were characterized by DLS and Zeta potential analysis, TEM microscopy, and FTIR spectroscopy. The effects of pH, temperature, MB concentration, amount of Liposome@PDA, and contact time on the adsorption process were investigated. Results showed that the highest adsorption capacity was obtained in weakly alkaline conditions (pH = 8.0) and that it could reach up to 395.4 mg g−1 at 298 K. In addition, adsorption kinetics showed that the adsorption behavior fits a pseudo-second-order kinetic model well. The equilibrium adsorption data, instead, were well described by Langmuir isotherm. Thermodynamic analysis demonstrated that the adsorption process was endothermic and spontaneous (ΔG0 = −12.55 kJ mol−1, ΔH0 = 13.37 kJ mol−1) in the investigated experimental conditions. Finally, the applicability of Liposome@PDA microspheres to model wastewater and the excellent reusability after regeneration by removing MB were demonstrated.