Novel biomimetic nanostructured lipid carriers for cancer therapy: preparation, characterization, and in vitro/in vivo evaluation.

Nanostructured lipid carriers (NLC) have become a research hotspot, wherein cancer-targeting effects are enhanced and side effects of chemotherapy are overcome. Usually, accelerated blood clearance (ABC) occurs after repeated injections, without changing the immunologic profile, despite PEGylation which prolongs the circulation function. To overcome these problems, we designed a red blood cell-membrane-coated NLC (RBCm-NLC), which was round-like, with a particle size of 60.33 ± 3.04 nm and a core-shell structure. Its stability was good, the drug paclitaxel (PTX) release from RBCm-PTX-NLC was less than 30% at pH7.4 and pH6.5, and the integrity of RBC membrane surface protein was maintained before and after preparation. Additionally, in vitro assays showed that, with the RBCm coating, the cellular uptake of the NLC by cancer cells was significantly enhanced. RBCm-NLC can avoid recognition by macrophage cells and prolong circulation time in vivo. In S180 tumor-bearing mice, the DiR-labeled RBCm-NLC group showed a stronger fluorescence signal and longer retention in tumor tissues, indicating a prompt tumor-targeting effect and extended blood circulation. Importantly, RBCm-PTX-NLC enhanced the antitumor effect and extended the survival period significantly in vivo. In summary, biomimetic NLC offered a novel strategy for drug delivery in cancer therapy.

Biodegradation of marine surface floating crude oil in a large-scale field simulated experiment.

Biodegradation of marine surface floating crude oil with hydrocarbon degrading bacteria, rhamnolipid biosurfactants, and nutrients was carried out by a large-scale field simulated experiment in this paper. After a 103 day experiment, for n-alkanes, the maximum biodegradation rate reached 71% and the results showed hydrocarbon degrading bacteria, rhamnolipid biosurfactants, and nutrients have a comprehensive effect. It also showed that rhamnolipid biosurfactants could shorten the biodegradation time through an emulsifying function; the nutrients could greatly increase the biodegradation rate by promoting HDB production. For PAHs, the chrysene series had higher weathering resistance. For the same series, the weathering resistance ability is C1- < C2- < C3- < C4-. After 53 days, no comprehensive effect occurred and more biodegradation was found for different n-alkanes in two pools which only had added rhamnolipid biosurfactants or nutrients, respectively. Except for C14, C15 and C16 sesquiterpanes, most of the steranes and terpanes had high antibiodegradability.

Lipopeptide biosurfactant production bacteria Acinetobacter sp. D3-2 and its biodegradation of crude oil.

In this work, a hydrocarbon-degrading bacterium D3-2 isolated from petroleum contaminated soil samples was investigated for its potential effect in biodegradation of crude oil. The strain was identified as Acinetobacter sp. D3-2 based on morphological, biochemical and phylogenetic analysis. The optimum environmental conditions for growth of the bacteria were determined to be pH 8.0, with a NaCl concentration of 3.0% (w/v) at 30 °C. Acinetobacter sp. D3-2 could utilize various hydrocarbon substrates as the sole carbon and energy source. From this study, we also found that the strain had the ability to produce biosurfactant, with the production of 0.52 g L(-1). The surface tension of the culture broth was decreased from 48.02 to 26.30 mN m(-1). The biosurfactant was determined to contain lipopeptide compounds based on laboratory analyses. By carrying out a crude oil degradation assay in an Erlenmeyer flask experiment and analyzing the hydrocarbon removal rate using gas chromatography, we found that Acinetobacter sp. D3-2 could grow at 30 °C in 3% NaCl solution with a preferable ability to degrade 82% hydrocarbons, showing that bioremediation does occur and plays a profound role during the oil reparation process.

Biodegradation of crude oil using an efficient microbial consortium in a simulated marine environment.

Ochrobactrum sp. N1, Brevibacillus parabrevis N2, B. parabrevis N3 and B. parabrevis N4 were selected when preparing a mixed bacterial consortium based on the efficiency of crude oil utilization. A crude oil degradation rate of the N-series microbial consortium reached upwards of 79% at a temperature of 25 °C in a 3.0% NaCl solution in the shake flask trial. In the mesocosm experiment, a specially designed device was used to simulate the marine environment. The internal tank size was 1.5 m (L)×0.8 m (W)×0.7 m (H). The microbial growth conditions, nutrient utilization and environmental factors were thoroughly investigated. Over 51.1% of the crude oil was effectively removed from the simulated water body. The escalation process (from flask trials to the mesocosm experiment), which sought to represent removal under conditions more similar to the field, proved the high efficiency of using N-series bacteria in crude oil degradation.

Fingerprinting and source identification of an oil spill in China Bohai Sea by gas chromatography-flame ionization detection and gas chromatography-mass spectrometry coupled with multi-statistical analyses.

This paper describes a case study in which advanced chemical fingerprinting and data interpretation techniques were used to characterize the chemical composition and determine the source of an unknown spilled oil reported on the beach of China Bohai Sea in 2005. The spilled oil was suspected to be released from nearby platforms. In response to this specific site investigation need, a tiered analytical approach using gas chromatography-mass spectrometry (GC-MS) and gas chromatography-flame ionization detection (GC-FID) was applied. A variety of diagnostic ratios of "source-specific marker" compounds, in particular isomers of biomarkers, were determined and compared. Several statistical data correlation analysis methods were applied, including clustering analysis and Student's t-test method. The comparison of the two methods was conducted. The comprehensive analysis results reveal the following: (1) The oil fingerprinting of three spilled oil samples (S1, S2 and S3) positively match each other; (2) The three spilled oil samples have suffered different weathering, dominated by evaporation with decrease of the low-molecular-mass n-alkanes at different degrees; (3) The oil fingerprinting profiles of the three spilled oil samples are positive match with that of the suspected source oil samples C41, C42, C43, C44 and C45; (4) There are significant differences in the oil fingerprinting profiles between the three spilled oil samples and the suspected source oil samples A1, B1, B2, B3, B4, C1, C2, C3, C5 and C6.

[Identification of crude oils in Bohai Sea by polycyclic aromatic hydrocarbon fingerprinting].

Crude oils from different sources have quite different polycyclic aromatic hydrocarbon (PAH) distributions. Also, many PAH compounds are more resistant to weathering than their saturated counterparts (n-alkanes and isoprenoids) and volatile alkylbenzene compounds, thus PAils become one of the most valuable classes of hydrocarbons for oil identification using fingerprinting. A reliable, effective, and accurate gas chromatography/mass spectrometry (GC/MS) method for the differentiation and source identification of crude oils by the use of PAH compounds is described. PAll components of 6 crude oil samples from 5 different platforms in 4 different oil fields in Bohal Sea were analyzed by GC/MS. Using different methods, such as the comparisons of original fingerprinting, characteristic information, and diagnostic ratios of PAHs, 6 crude oil samples were identified completely, which showed distinctive characteristics of the same platform oils. Although distinction was diminutive, it can still be identified by GC/MS. PAHs could be used in weathering check of spilled oils in identification and to ensure the correctness of the identification.