Sensitization of Antibiotic-Resistant Gram-Negative Bacteria to Photodynamic Therapy via Perfluorocarbon Nanoemulsion.

With the merits of excellent efficacy, safety, and facile implementation, antibacterial photodynamic therapy (APDT) represents a promising means for treating bacterial infections. However, APDT shows an unsatisfactory efficacy in combating antibiotic-resistant Gram-negative bacteria due to their specific cell wall structure. In this work, we report a perfluorocarbon nanoemulsion (Ce6@FDC) used as a multifunctional nanocargo of photosensitizer and oxygen for sensitizing antibiotic-resistant Gram-negative bacteria to APDT. Ce6@FDC was fabricated via ultrasonic emulsification with good colloidal stability, efficient Ce6 and oxygen delivery, and excellent photodynamic activity. Meanwhile, Ce6@FDC could strongly bind with Gram-negative Acinetobacter baumannii (A. baumannii) and Escherichia coli (E. coli) via electrostatic interaction, thus leading to notable photodynamic bactericidal potency upon irradiation. In addition, oxygenated Ce6@FDC also exhibited a remarkable efficacy in eradicating Gram-negative bacteria biofilm, averaging five log units lower than the Ce6 group under identical conditions. Taken together, we demonstrate that photodynamic perfluorocarbon nanoemulsion with oxygen-delivery ability could effectively kill planktonic bacteria and remove biofilm, representing a novel strategy in fighting against antibiotic-resistant Gram-negative bacteria.

Highly efficient photocatalytic oxidation of antibiotic ciprofloxacin using TiO2@g-C3N4@biochar composite.

In this present study, a novel indirect Z-scheme TiO2@g-C3N4@biochar (TiO2@g-C3N4@BC) composite photocatalyst was successfully fabricated and characterized with SEM, TEM, EDS, XRD, FTIR, PL, XPS, and UV-vis DRS. The photocatalytic degradation behavior of ciprofloxacin (CIP) on the TiO2@g-C3N4@BC was evaluated under UV-vis and visible light irradiation, and the possible reaction mechanism of photocatalytic oxidation of CIP on the TiO2@g-C3N4@BC was explained. The TiO2@g-C3N4@BC composite photocatalyst exhibited stronger photocatalytic oxidation activity for CIP in comparison with TiO2, g-C3N4, TiO2@BC, and TiO2@g-C3N4. After 60 min of UV-vis and visible light irradiation, the photocatalytic removal efficiency of CIP by TiO2@g-C3N4@BC was 99.3 and 89.2%, respectively. The photocatalytic removal performance of CIP was affected by the initial concentration of CIP, catalyst dosage, and pH value. The composite photocatalyst presented excellent stability and reusability after five cycles. An indirect Z-scheme principle of the CIP photocatalytic oxidation reaction on TiO2@g-C3N4@BC was clearly proposed, and the whole process of photocatalytic degradation was the results of the interaction between CIP and reactive active species (·O2-, h+, and ·OH), of which ·O2- is the main active substance. Four CIP degradation pathways were proposed. This work may provide an effective strategy to remove antibiotics in wastewater.

Self-assembly delivery system based on small-molecule camptothecin prodrug for treatment of colorectal carcinoma.

The aim of this study was to prepare small-molecule camptothecin (CPT) prodrugs and evaluate their effectiveness in colorectal carcinoma therapy. Prodrug nanoparticles (NPs) were physicochemically characterized and evaluated for their cytotoxicity in human colon cancer (HCT116) cell lines. The antitumor efficacy of the NPs was evaluated in HCT116 tumor-bearing mice. The prepared NPs exhibited high drug loading capacity (32% of CPT w/w) and also kept a high active lactone fraction of CPT (>85%) during circulation. The NPs were internalized into tumor cells efficiently compared with free drug and significantly enhanced the drug's therapeutic efficacy. The developed small-molecule CPT prodrug NPs could be a promising strategy in the clinical therapy of colorectal carcinoma.

Exploring soil erosion trajectories and their divergent responses to driving factors: a model-based contrasting study in highly eroded mountain areas.

Soil erosion threatens environmental sustainability worldwide. Exploring the trajectories of soil erosion and associated drivers is of great significance for combating land degradation. This study selected the highly eroded Loess Plateau (LP) and Karst Plateau (KP) as contrasting regions to monitor soil erosion dynamics. Monitoring was performed by applying the Revised Universal Soil Loss Equation based on a GIS platform and multi-source input data to investigate associated drivers. The results established that soil erosion in both regions was substantially reduced by ecological restoration projects and significant land use/cover conversions. Landscape and geomorphological variables were found to be the dominant factors controlling soil erosion in the LP and KP, as they influenced land use patches and geomorphological patterns, respectively. The correlations between fragmentation metric indices and soil erosion indicated that the appropriately intensive fragmentation in the LP could mitigate or prevent soil erosion by disturbing its formation and transportation and ultimately positively influenced soil erosion control. Geomorphological patterns were also determinative factors, particularly for the KP, where almost all geomorphological variables were significantly correlated with the erosion modulus. Owing to the peculiar landform and landscape conditions in karst areas and loess hilly-gully areas, geomorphological and landscape variables should be considered when determining the main factors affecting soil erosion processes and integrated into the forecasting model to improve the accuracy of the simulation. The findings of this study are expected to (i) improve the efficacy of soil erosion control and (ii) promote the sustainable planning and management of land and soil resources.

Adsorption of dichromate ions from aqueous solution onto magnetic graphene oxide modified by ß-cyclodextrin.

In this work, the ß-cyclodextrin modified magnetic graphene oxide (ß-CD/MGO) composite was fabricated by the in situ co-precipitation method and characterized by Fourier transform-infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM), and particle size analysis. The adsorption behavior of dichromate ions on the ß-CD/MGO was investigated, and the mechanism of adsorption was also studied using FT-IR and XPS. The results from SEM and TEM showed that the graphene oxide (GO) layer became rough, and many fine particles were attached after compounding with ferroferric oxide and ß-cyclodextrin. The characterization results of FT-IR and XPS show that that ß-cyclodextrin and ferroferric oxide have been perfectly compounded to the graphene oxide layer and ß-CD/MGO has a particle size of about 460 nm, a specific surface area of 252.3 m2g-1, and a saturation magnetization of 73.5 emu g-1. The adsorption amount of dichromate ions on the ß-CD/MGO is affected by pH, adsorbent dosage, and adsorption time. Kinetic studies showed that the adsorption process followed a pseudo-second-order kinetic model. Equilibrium data agreed very well with the Langmuir model, the maximum adsorption amount of dichromate ions on the ß-CD/MGO was 49.95 mg g-1. After five successive adsorbent reuses, the reuse rate is still 73%, indicating the excellent potential reusability of ß-CD/MGO adsorbent. ß-CD/MGO exhibits excellent adsorption performance for dichromate ions. As an environmentally friendly magnetic adsorbent, ß-CD/MGO is suitable for the treatment of dichromate-containing wastewater.

Preparation and evaluation of tumour microenvironment response multistage nanoparticles for epirubicin delivery and deep tumour penetration.

Poor tumour penetration became a major challenge for the use of nanoparticles in anticancer therapy. To further enhance the tumour penetration efficiency, we developed a tumour-microenvironment-responsive multistage drug delivery system which was formed layer by layer via electrostatic interaction with cationic drug-loaded nanoparticles, hyaluronidase (HAase) and iRGD-modified gelatin (G-iRGD). The drug-loaded nanoparticles were formed by self-assembling mPEG-PDPA-PG and encapsulation with epirubicin (EPI). Due to the protonation of tertiary amine groups of PDPA segment in acid environment, mPEG-PDPA-PG could enhance the lysosomal escape and the intracellular release of EPI. This NPs/HAase/G-iRGD delivery system showed great biocompatibility in vitro, confirmed by MTT method. In vitro spherical tumour model penetration and in vivo tumour permeability investigation showed HAase coated NPs-EPI (NPs-EPI/HAase) could significantly enhance its penetrating efficiency. The NPs-EPI/HAase could assist in breaking down the hyaluronic acid (HA), which was a key component of extracellular matrix and thereby improving mass transport within the solid tumours. The flow cytometry studies showed that G-iRGD coated NPs-EPI (NPs-EPI/G-iRGD) was more easily taken up by HepG2 cells than gelatin coated NPs-EPI (NPs-EPI/G), which revealed the active targeting ability of iRGD. The results proved that this NPs/HAase/G-iRGD delivery system showed promising potential in enhancing tumour penetration efficiency.

Lipid nanoparticle-based co-delivery of epirubicin and BCL-2 siRNA for enhanced intracellular drug release and reversing multidrug resistance.

At present, combined therapy has become an effective strategy for the treatment of cancer. Co-delivery of the chemotherapeutic drugs and siRNA can more effectively inhibit tumor growth by nano drug delivery systems (NDDSs). Here, we prepared and evaluated a multifunctional envelope-type nano device (MEND). This MEND was a kind of composite lipid-nanoparticles possessing both the properties of liposomes and nanoparticles. In this study, an acid-cleavable ketal containing poly (ß-amino ester) (KPAE) was used to bind siBCL-2 and the KPAE/siBCL-2 complexes were further coated by epirubicin (EPI) containing lipid to form EPI/siBCL-2 dual loaded lipid-nanoparticles. The results showed that the average size of EPI/siBCL-2-MEND was about 120 nm, and the average zeta potential was about 41 mV. The encapsulation efficiency (EE) of EPI and siBCL-2 was 86.13% and 97.07%, respectively. EPI/siBCL-2 dual loaded lipid-nanoparticles showed enhanced inhibition efficiency than individual EPI-loaded liposomes on HepG2 cells by MTT assay. Moreover, western blot experiment indicated co-delivery of EPI/siBCL-2 can significantly down-regulate the expression of P-glycoprotein (P-gp), while free EPI and EPI-loaded liposomes up-regulated it. Therefore, the strategy of co-delivering EPI and siBCL-2 simultaneously by lipid-nanoparticles showed promising potential in reversing multidrug resistance of tumor cells.

Preparation and evaluation of a novel bonded imidazolium ionic liquid as stationary phase for gas chromatography.

1-Butyl-3-[(3-trimethoxysilyl)propyl]imidazolium chloride ionic liquid was synthesized and chemically modified onto the inner wall of a fused capillary column as a stationary phase for gas chromatography. The 1-butyl-3-[(3-trimethoxysilyl)propyl]imidazolium chloride ionic liquid bonded capillary column was evaluated in detail. The results revealed that the ionic liquid bonded capillary column exhibited high column efficiency of 1.08 × 104 plates/m, and good chromatographic separation selectivity (α) for polar and non-polar substances, and a good thermal stability between room temperature and 400°C. Moreover, the determination of thermodynamic parameters and the linear solvation energy relationship were further carried out. The results indicated that the chromatographic retention of each probe molecule on the ionic liquid bonded stationary phase was an enthalpy-driven process, and the system constants of the linear solvation energy relationship signified that the dispersion interaction, the hydrogen bonding acidity and hydrogen bonding basicity were dominant interactions between probes and stationary phase among five interactions during the chromatographic separation. However, the contribution of each specific interaction for the stationary phase is ranked as the dispersion interaction > the hydrogen bonding basicity > the hydrogen bonding acidity.

[Prokaryotic expression, identification and histo-localization of the Taenia asiatica enolase gene].

OBJECTIVE: To express enolase gene of Taenia asiatica, investigate the immunoreactivity of the recombinant TaENO protein, and immuno-histo-localize the presence of the recombinant TaENO in adults of T. asiatica. METHODS: The gene encoding enolase of T. asiatica (TaENO) was cloned by high throughput sequencing from the cDNA library of adult T. asiatica. The coding region of TaENO was amplified by PCR, and cloned into a prokaryotic expression vector pET-30a (+). The recombinant plasmid was transformed into E. coli BL-21/DE3 and followed by expression of the protein induced by IPTG. The protein was purified by Ni-IDA affinity chromatography, and tested by SDS-PAGE. Its immunoreactivity was examined by Western blotting. The mice were immunized subcutaneously with purified TaENO formulated in Freund's adjuvant. Serum samples were collected and analyzed for specific antibodies by ELISA. The localization of TaENO in adult worms was demonstrated by immunofluorescent technique. RESULTS: The recombinant expression plasmid was identified by PCR, double endonuclease digestion and sequencing. The recombinant TaENO was about Mr 47 000 with a concentration of 0.37 mg/ml. It was recognized by antisera of SD rats immunized with TaENO, sera of taeniasis patients and sera of infected swine. The immunofluorescence assay revealed that TaENO immune serum located in the tegument of T. asiatica adult. CONCLUSION: The TaENO gene has been expressed with immunoreactivity, and the recombinant TaENO is immunolocalized in the tegument of T. asiatica adult.