Lihong Deng

The influence of dispersed phases on polyamide/ZIF-8 nanofiltration membranes for dye removal from water

To investigate the influence of different dispersed phases on polyamide (PA)/ZIF-8 membrane properties, three different fabrication methods for dispersing ZIF-8 nanoparticles were developed to prepare the PA/ZIF-8(A) membranes (in aqueous phases), PA/ZIF-8(O) membranes (in organic phases), and PA/ZIF-8(B) membrane (in both the aqueous and organic phases), respectively. These PA/ZIF-8 membranes were characterized in detail by XRD, DLS, XPS, FTIR, SEM, AFM, and contact angle measurements, the results showed that the structure properties of the PA/ZIF-8 membranes were significantly dependent on the dispersed phases and ZIF-8 concentrations. The nanofiltration performance of the PA/ZIF-8 membranes was investigated for application in removing dye (Congo red) from water. For the PA/ZIF-8(A) and PA/ZIF-8(O) membranes, the flux and rejection were both improved at 0.05–0.15% (w/v) ZIF-8 concentration in a single phase and the PA/ZIF-8(O) membranes exhibited slightly higher fluxes than the PA/ZIF-8(A) membranes due to the better dispersion of hydrophobic ZIF-8 in organic phases. The PA/ZIF-8(B) membrane prepared by 0.10% (w/v) ZIF-8 concentration in both the aqueous and organic phases showed the best membrane performance among all prepared PA/ZIF-8 membranes: the flux significantly increased to two times that of the pure PA membrane, and the rejection was nearly 100%. Compared with the PA/ZIF-8(A) and PA/ZIF-8(O) membranes, the improvement on membrane performance of the PA/ZIF-8(B) membrane was achieved by a combination of the high ZIF-8 loading, good ZIF-8 distribution, and fewer ZIF-8 aggregates in the PA/ZIF-8 selective layer.

Self-assembled targeted folate-conjugated eight-arm-polyethylene glycol–betulinic acid nanoparticles for co-delivery of anticancer drugs

In this study, a targeted nanoparticle platform for co-delivery of anticancer drugs based on folate-conjugated eight-arm-polyethylene glycol-betulinic acid (F-8arm-PEG-BA) was first presented. F-8arm-PEG-BA was synthesized by introducing target molecules (folate) and drug molecules (betulinic acid, BA) to hydrophilic molecules (8arm-PEG). Then another anticancer drug, hydroxycamptothecin (HCPT), was encapsulated into the self-assembled nanoparticles from the conjugate by a simple nanoprecipitation method. These F-8arm-PEG-BA/HCPT nanoparticles (NPs) had a small size (∼120 nm), acceptable critical aggregation concentration (∼64.8 μg mL-1), and high drug loading (∼18 wt% BA and ∼16 wt% HCPT). Compared to the free drugs, the nanoparticles significantly improved the cellular cytotoxicity and exhibited an obvious synergistic effect by the co-delivery of two different anticancer drugs, BA and HCPT. Pharmacokinetics study revealed the nanoparticles could prolong the circulation of BA and HCPT in the blood. In vivo studies indicated that the nanoparticles enhanced tumor targeting and antitumor activity with lower systemic toxicity. In conclusion, F-8arm-PEG-BA/HCPT NPs have great potential for targeted chemotherapy for cancer.

Cellulose-graft-poly(L-lactic acid) nanoparticles for efficient delivery of anti-cancer drugs

Cellulose based carriers have the potential for sustained release of drugs, which can protect drugs and deliver them to the target site. Herein, BA-loaded cellulose-graft-poly(l-lactic acid) nanoparticles (CE-g-PLLA/BA NPs) were fabricated by employing cellulose (CE) and poly(l-lactic acid) (PLLA) as materials and betulinic acid (BA) as a model drug. Both drug-free and BA-loaded nanoparticles were spherical in shape with a uniform size of 100-170 nm. The release of BA from CE-g-PLLA/BA NPs was relatively slow. In vitro cytotoxicity studies with A549 and LLC cell lines suggested that CE-g-PLLA/BA NPs were slightly superior to BA in antitumor activity and CE-g-PLLA NPs were non-toxic. The antitumor effect of the CE-g-PLLA/BA NPs in a mouse tumor xenograft model exhibited much better tumor inhibition efficacy and fewer side effects than that of BA, strongly supporting their use as efficient carriers for anti-cancer therapy.

NiO-PTA supported on ZIF-8 as a highly effective catalyst for hydrocracking of Jatropha oil

Nickel oxide (NiO) and phosphotungstic acid (PTA) supported on a ZIF-8 (NiO-PTA/ZIF-8) catalyst was first synthesized and it showed high activity and good selectivity for the hydrocracking of Jatropha oil. The catalyst was characterized by SEM, SEM-EDS, TEM, N2 adsorption, FT-IR, XRD and XPS. Compared with the NiO-PTA/Al2O3 catalyst, the selectivity of C15-C18 hydrocarbon increased over 36%, and catalytic efficiency increased 10 times over the NiO-PTA/ZIF-8 catalyst. The prepared NiO-PTA/ZIF-8 catalyst was stable for a reaction time of 104 h and the kinetic behavior was also analyzed. This catalyst was found to bypass the presulfurization process, showing promise as an alternative to sulfided catalysts for green diesel production.

Novel Multiarm Polyethylene glycol-Dihydroartemisinin Conjugates Enhancing Therapeutic Efficacy in Non-Small-Cell Lung Cancer

The clinical application of dihydroartemisinin (DHA) has been hampered due to its poor water-solubility. To overcome this hurdle, we devised a novel polymer-drug conjugate, multiarm polyethylene glycol-dihydroartemisinin (PEG-DHA), made by linking DHA with multiarm polyethylene glycol. Herein, we investigated PEG-DHA on chemical structure, hydrolysis, solubility, hemolysis, cell cytotoxicity in vitro, and efficacy in vivo. The PEG-DHA conjugates have showed moderate drug loadings (2.82 ~ 8.14 wt%), significantly good water-solubilities (82- ~ 163-fold of DHA), excellent in vitro anticancer activities (at concentrations ≥8 μg/ml, showed only 15–20% cell viability) with potency similar to that of native DHA, and long blood circulation half-time (5.75- ~ 16.75-fold of DHA). Subsequent tumor xenograft assays demonstrated a superior therapeutic effect of PEG-DHA on inhibition of tumor growth compared with native DHA. The novel PEG-DHA conjugates can not only improve the solubility and efficacy of DHA but also show the potential of scale-up production and clinical application.

Water soluble multiarm-polyethylene glycol–betulinic acid prodrugs: design, synthesis, and in vivo effectiveness

Betulinic acid (BA) is a new type of cancer-fighting drug, but it is limited by its low water solubility and relatively short half-life in clinical applications. To overcome the shortcomings, BA prodrugs were prepared by using multiarm-polyethylene glycol linkers. The prodrugs exhibited high drug loading capacity (3.26–11.81 wt%), high water solubility (290–750 fold of free BA), and excellent in vitro anticancer activity. Subsequent tumor xenograft assays demonstrated the superior therapeutic effect of BA prodrugs on inhibition of tumor growth compared with free BA. Multiple intravenous injection of BA prodrugs equivalent to 10 mg of BA per kg resulted in the decrease of an established implanted murine Lewis lung carcinoma (percent tumor growth inhibition after treatment on day 20, 72.1–90.7%) in mice. These results strongly supported that the BA prodrugs are promising for cancer therapy.

Hydroprocessing of Jatropha Oil for Production of Green Diesel over Non-sulfided Ni-PTA/Al2O3 Catalyst

The non-sulfided Ni-PTA/Al2O3 catalyst was developed to produce green diesel from the hydroprocessing of Jatropha oil. The Ni-PTA/Al2O3 catalyst was prepared by one-pot synthesis of Ni/Al2O3 with the co-precipitation method and then impregnanting Ni/Al2O3 with PTA solution. The catalysts were characterized with BET, SEM-EDX, TEM, XRD, XPS, TGA and NH3-TPD. The Ni and W species of the Ni-PTA/Al2O3 catalyst were much more homogeneously distributed on the surface than that of commercial Al2O3. Catalytic performance in the hydroprocessing of Jatropha oil was evaluated by GC. The maximum conversion of Jatropha oil (98.5 wt%) and selectivity of the C15-C18 alkanes fraction (84.5 wt %) occurred at 360 °C, 3.0 MPa, 0.8 h−1. The non-sulfided Ni-PTA/Al2O3 catalyst is more environmentally friendly than the conventional sulfided hydroprocessing catalyst, and it exhibited the highest catalytic activity than the Ni-PTA catalyst supported with commercial Al2O3 grain and Al2O3 powder.

A Non-sulfided flower-like Ni-PTA Catalyst that Enhances the Hydrotreatment Efficiency of Plant Oil to Produce Green Diesel.

The development of a novel non-sulfided catalyst with high activity for the hydrotreatment processing of plant oils, is of high interest as a way to improve the efficient production of renewable diesel. To attempt to develop such a catalyst, we first synthesized a high activity flower-like Ni-PTA catalyst used in the hydrotreatment processes of plant oils. The obtained catalyst was characterized with SEM, EDX, HRTEM, BET, XRD, H2-TPR, XPS and TGA. A probable formation mechanism of flower-like Ni(OH)2 is proposed on the basis of a range of contrasting experiments. The results of GC showed that the conversion yield of Jatropha oil was 98.95%, and the selectivity of C11-C18 alkanes was 70.93% at 360 °C, 3 MPa, and 15 h−1. The activity of this flower-like Ni-PTA catalyst was more than 15 times higher than those of the conventional Ni-PTA/Al2O3 catalysts. Additionally, the flower-like Ni-PTA catalyst exhibited good stability during the process of plant oil hydrotreatment.

Synthesis, characterization and adsorption performance of molecularly imprinted nanoparticles for tripterine by precipitation polymerization

Synthesis of molecularly imprinted nanoparticles for tripterine with good selectivity and high adsorption capacity by precipitation polymerization is presented for the first time, in which tripterine, methacrylic acid and ethylene glycol dimethacrylate were used as a template molecule, functional monomer and cross-linker, respectively. The preparation conditions of molecularly imprinted nanoparticles were optimized, and the optimal molar ratio of template to functional monomer to cross-linker was 1 : 3 : 3. And non-imprinted polymers (NIPs) for control experiments were also prepared. The nanoparticles were characterized using a scanning electron microscope, laser particle size analyzer and BET, respectively. The results indicated that the imprinted nanoparticles were spherical in shape and the size was relatively uniform. Selectivity analysis suggested that the obtained imprinted nanoparticles could specifically recognize tripterine. In addition, adsorption kinetics and adsorption isotherm of the imprinted nanoparticles were utilized to study the binding characteristics of the imprinted nanoparticles. The results revealed that the imprinted nanoparticles had high adsorption capacity and the maximum adsorption capacity of tripterine on the imprinted particles was up to 145.97 mg g−1. In potential application research, this adsorbent was satisfactorily employed as a solid-phase extraction sorbent to extract TTR in urine samples.

A self-assembled nanoparticle platform based on poly(ethylene glycol)–diosgenin conjugates for co-delivery of anticancer drugs

Diosgenin (DGN) is a steroidal saponin from a therapeutic herb. It is reported to be a kind of potential natural antitumor drug. However, clinical application of diosgenin in cancer therapy is limited due to undesirable pharmaceutical characteristics such as its consequently poor solubility and low bioavailability. Here we developed a nanoparticle platform based on poly(ethylene glycol)–diosgenin (mPEG–DGN) conjugates for co-delivery of anticancer drugs. Firstly, to improve the solubility and bioavailability of DGN, the amphiphilic conjugates mPEG–DGN were made by linking DGN with mPEG. Then they self-assembled stable nanoparticles to deliver another anticancer drug hydroxycamptothecin (HCPT) by a simple nanoprecipitation method. The obtained nanoparticles possessed the appropriate size, high drug loading efficiency of diosgenin and HCPT, slow release of the drugs and high synergistic effects. Hence, the mPEG–DGN nanoparticle is a promising drug delivery system for cancer therapy.