Muricauda onchidii sp. nov., isolated from a marine invertebrate from South China Sea, and transfers of Flagellimonas algicola, Flagellimonas pacifica and Flagellimonas maritima to Muricauda algicola comb. nov., Muricauda parva nom. nov. and Muricauda aurantiaca nom. nov., respectively, and emended description of the genus Muricauda.

An aerobic, Gram-stain-negative, rod-shaped and non-motile strain (XY-359T) was isolated from the mouth of a marine invertebrate Onchidium species from the South China Sea. It grew at pH 6.0-8.5 (optimum, pH 7.5), at 15-37 °C (optimum, 30 °C) and in the presence of 0.5-4.5 % (w/v) NaCl (optimum, 2.5 %). It could not hydrolyse Tweens 20, 40, 60 or 80 and no flexirubin-type pigments were produced. The major polar lipids were phosphatidylethanolamine, one unidentified aminolipid, six unidentified phospholipids and two unidentified polar lipids. The major fatty acids were iso-C17:0 3-OH, iso-C15:1 G and iso-C15:0 3-OH. The respiratory quinone was MK-6. Strain XY-359T showed the greatest degree of 16S rRNA sequence similarity to Flagellimonas algicola AsT0115T (96.54 %), followed by Muricauda flava DSM 22638T (96.27 %). Phylogenetic analysis based on 16S rRNA gene sequences and 31 core genes indicated that strain XY-359T belongs to the genus Muricauda. The genome size of strain XY-359T was 4 207 872 bp, with 39.1 mol% of DNA G+C content. The average nucleotide identity and digital DNA-DNA hybridization values between strain XY-359T and F. algicola AsT0115T were 74.58 % and 18.5 %, respectively, and those between strain XY-359T and M. flava DSM 22638T were 74.2 % and 18.3 %. The combined phenotypic, chemotaxonomic and phylogenetic data suggest that strain XY-359T represents a novel species of the genus Muricauda, for which the name Muricauda onchidii sp. nov. is proposed. The type strain is XY-359T (=MCCC 1K03658T =KCTC 72218T). Moreover, based on the proposal of nesting Spongiibacterium and Flagellimonas within Muricauda by García (Validation List No. 193) and the analyses of phylogenetic trees and average amino acid identities in this study, the transfers of F. algicola, F. pacifica and F. maritima to the genus Muricauda as Muricauda algicola comb. nov., Muricauda parva nom. nov. and M. aurantiaca nom. nov., respectively, are proposed, with an emended description of the genus Muricauda.

Three dimensionally printed nitrocellulose-based microfluidic platform for investigating the effect of oxygen gradient on cells.

In this article, we present a novel nitrocellulose-based microfluidic chip with 3-dimensional (3D) printing technology to study the effect of oxygen gradient on cells. Compared with conventional polydimethylsiloxane (PDMS) chips of oxygen gradient for cell cultures that can only rely on fluorescence microscope analysis, this hybrid nitrocellulose-based microfluidic platform can provide a variety of analysis methods for cells, including flow cytometry, western blot and RT-PCR, because the nitrocellulose-based chips with cells can be taken out from the growth chambers of 3D printed microfluidic chip and then used for cell collection or lysis. These advantages allow researchers to acquire more information and data on the basic biochemical and physiological processes of cell life. The effect of oxygen gradient on the zebrafish cells (ZF4) was used as a model to show the performance and application of our platform. Hypoxia caused the increase of intercellular reactive oxygen species (ROS) and accumulation of hypoxia-inducible factor 1α (HIF-1α). Hypoxia stimulated the transcription of hypoxia-responsive genes vascular endothelial growth factor (VEGF) and induced cell cycle arrest of ZF4 cells. The established platform is able to obtain more information from cells in response to different oxygen concentration, which has potential for analyzing the cells under a variety of pathological conditions.

Combination of Curcumin and Paclitaxel Liposomes Exhibits Enhanced Cytotoxicity Towards A549/A549-T Cells and Unaltered Pharmacokinetics.

Background: Combination chemotherapy of chemo-drugs and natural herbal drugs has been shown to be more advantageous than individual treatment with respect to enhancing cytotoxicity, alleviating toxicity and controlling the development of multidrug resistance (MDR). Purpose: The goal of this study is to construct a combined drug delivery system of curcumin liposomes (CUR-LPs) and paclitaxel liposomes (PTX-LPs) to enhance the anticancer activity and reverse the MDR of PTX. Methods: CUR-LPs and PTX-LPs were prepared by solvent evaporation method with optimal formulation composition. MTT assay was used to assess the effect of the combination of CUR-LPs and PTX-LPs treatments on the proliferation of A549/A549-T cells. In addition, the pharmacokinetic behaviors of the combination treatments were evaluated by HPLC. Results : The mixed liposomes were found to have negative zeta-potential (-17.91 ± 1.21 mV) and relatively uniform particle size (105.88 ± 3.19 nm) with a low polydispersity index (0.21 ± 0.016). IC50 of PTX for combination of CUR-LPs and PTX-LPs decreased in the range of 1.47-2.9 times and 1.59-2.5 times compared to the free-drug counterparts in A549 and A549-T cells, respectively. Superior cytotoxicity and higher synergy (CI< 0.4) were observed for the combination treatment with ratio of 40:1 (CUR-LPs:PTX-LPs) compared with the free-drug counterparts in both cell lines tested. Following intravenous administration in rats, liposomes presented higher bioavailability (CUR-LPs: 9.02 fold; PTX-LPs: 7.32 fold) compared to free drugs. Co-administration did not alter the respective pharmacokinetic behaviors. Conclusion: Overall, the present study presents a promising strategy for the development of compound formulations of CUR and PTX.

Preparation and characterization of magnetic cationic liposome in gene delivery.

Low transfection efficiency in vivo and failure to deliver therapeutic nucleic acids to the target organs limit the use of cationic liposomes (CLs) in gene therapy. Magnetic drug targeting (MDT) was applied in this study to improve the transfection efficiency and overcome the limitations. Magnetic cationic liposomes (MCLs) were prepared by incorporating MAG-T (magnetite) into CLs. The inclusion of relatively high concentration of MAG-T significantly increased the size of liposomes/lipoplexes, reduced the zeta potential, and decreased the cell viability. The transfection efficiency of MCLs in gene delivery was evaluated by using plasmid DNA (pDNA) containing a luciferase reporter gene in THLE-3 cells. Results suggested that the transfection efficiency of MCLs/pDNA complexes with a relatively lower content of MAG-T (0.75 mg/ml) was the same as that of CLs/pDNA complexes without a magnetic field but was higher (about 2.6-fold) with magnetic induction. Finally, using MCLs/pDNA complexes and a static magnetic field placed over the liver of rats, luciferase reporter gene expression in the liver increased as compared to MCLs/pDNA complexes and CLs/pDNA complexes in the absence of an external magnetic field.

[Preliminary study on sea cucumber saponin-nobiliside A liposome and its hemolytic activity].

Nobiliside A (Nob A) liposomes were prepared. Its assay method of content and encapsulation efficiency (EE) were established, and hemolytic activity with Nob A solution in vivo and in vitro were compared. Preparative method, phospholipid content, ratio of phospholipid to cholesterol and ratio of drug to lipids were optimized by single factor exploration. According to the optimized results, 3 batches of Nob A liposomes were prepared, then high performance liquid chromatography coupled with evaporative light scattering detector (HPLC-ELSD) method was used to determine the content of Nob A and minicolumn centrifugation method to determine EE, transmission electron microscope was used to detect the morphology and laser scatter analysis to evaluate particle sizes of the liposomes. The hemolytic activity was studied both in vivo and in vitro. The results indicated that HPLC-ELSD method and minicolumn centrifugation method used in this study are simple, applicable and accurate for the determination of the content and EE of Nob A liposome respectively . Nob A liposomes have a high EE with spherical shape and uniform size by using the film ultrasonication technique. When the ratio of phospholipid to cholesterol was 2:1 and the ratio of Nob A to lipids was 1:40, the mean EE of Nob A liposomes was 95.7% and the mean diameter was 87.6 nm. Liposomes inhibited the hemolytic activity of Nob A in vivo and in vitro sharply. As for its low hemolytic activity in vivo and in vitro, Nob A liposomes are optimistic to be used by intravenous injection.

Lung-targeting drug delivery system of baicalin-loaded nanoliposomes: development, biodistribution in rabbits, and pharmacodynamics in nude mice bearing orthotopic human lung cancer.

The present study aims to develop a kind of novel nanoliposomes for the lung-targeting delivery system of baicalin as a Chinese medicine monomer. Baicalin-loaded nanoliposomes were prepared by the effervescent dispersion and lyophilized techniques. Baicalin-loaded nanoliposomes had an average particle size of 131.7±11.7 nm with 0.19±0.02 polydispersity index, 82.8%±1.24% entrapment efficiency and 90.47%±0.93% of yield and sustaining drug release effect over 24 h and were stable for 12 months at least. In vitro no hemolytic activity was observed for the experimental drug concentration. After intravenous administration of baicalin-loaded nanoliposomes to rabbits, drug concentration in the lungs was the highest among the tested organs at all time points and was significantly higher than that of its solution. For the targeting parameters, the relative intake rate and the ratio of peak concentration of lung were 4.837 and 2.789, respectively. Compared with plasma, liver, spleen, and kidney, the ratios of targeting efficacy (Te)liposomes to (Te)injection of lung were increased by a factor of 14.131, 1.893, 3.357, and 3.470, respectively. Furthermore, the results showed that the baicalin-loaded nanoliposomes did not induce lung injury. Importantly, baicalin-loaded nanoliposomes showed better antitumor therapeutic efficacy in the nude mice bearing orthotopic human lung cancer with the median survival time of blank liposomes (11.40±0.16 days), baicalin solution (17.30±0.47 days), and baicalin-loaded nanoliposomes (25.90±0.53 days). Therefore, the liposome is a promising drug carrier with an excellent lung-targeting property and therapeutic effect for the treatment of lung disease, such as lung cancer.

Preparation, pharmacokinetics and biodistribution of baicalin-loaded liposomes.

Baicalin (BA) is a major constituent of Scutellaria baicalensis Georgi, a medicinal herb. Previous pharmacokinetic studies of BA showed its low oral bioavailability. The aim of the present study was to develop a novel BA-loaded liposome (BA-LP) to enhance oral bioavailability. BA-LP, composed of BA, Tween(®) 80, Phospholipon(®) 90H, and citric acid at weight ratio of 96/50/96/50, respectively, was prepared by the effervescent dispersion technique and characterized in terms of morphology, size, zeta potential, encapsulation efficiency, and the in vitro release. Pharmacokinetics and biodistribution studies were carried out in rats after oral administration of BA-LP and a carboxymethyl cellulose suspension containing BA (BA-CMC) as a control. BA-LP exhibited a spherical shape by transmission electron microscopy observation. BA-LP had a mean particle size of 373±15.5 nm, zeta potential of -20.1±0.22 mV, and encapsulation efficiency of 82.7%±0.59%. The BA-LP showed a sustained-release behavior, and the in vitro drug-release kinetic model fit well with the Weibull distribution equation: lnln (1/(1-Q)) =0.609 lnt -1.230 (r=0.995). The oral bioavailability and the peak concentration of the BA-LP was threefold and 2.82-fold that of BA-CMC, respectively. The in vivo distribution results indicated that drug concentrations were significantly increased in the liver, kidney, and lung in the case of BA-LP, which were 5.59-fold, 2.33-fold, and 1.25-fold higher than those of BA-CMC, respectively. In conclusion, the study suggested that BA-LP might be a potential oral drug delivery system to improve bioavailability of BA.

Development of nobiliside A loaded liposomal formulation using response surface methodology.

To reduce the hemolysis and toxicity of nobiliside A (Nob), liposomes were used as a carrier in this study. Response surface methodology (RSM) based on central composite rotatable design (CCRD) was applied for formulation optimization. Phosphatidyl choline (PC) proportion, cholesterol (CH) proportion, and lipids/drug ratio were selected as the independent variables while the encapsulation efficiency (EE) and hemolytic rate (HR) of the liposomes as the dependent variables. The results indicated CH proportion and lipids/drug ratio were the major contributing variables for EE and PC/CH ratio was the major contributing variables for HR. The optimum formulation of Nob liposomes, in which PC proportion of 2% (w/v), CH proportion of 0.9% (w/v), and lipids/drug ratio (w/w) of 40, had higher EE (>95%) and lower HR (<1% at the concentration of 80 microg mL(-1)) with spherical shape and uniform sizes. The intravenous LD50 increased to 9.5 mg kg(-1) compared to 4.1 mg kg(-1) of Nob solution. In conclusion, the liposome was a safety and effective carrier for intravenous Nob.