查找使用阿拉丁产品的科研文献

Unveiling the Oral Therapeutic Promise of 5-Fluorouracil-Laden Thiol-Chitosan-Coated Metal-Organic Frameworks

Yang Chen,Cai Peng

Metal-organic frameworks (MOFs), consisting of both organic linkers and metallic ions, are expected to be excellent drug delivery agents for the treatment of cancer. However, the stability of MOF in the gastrointestinal tract remains to be resolved. In this study, we synthesized a MOF, namely Zr-NDC. Next, a thiolated chitosan (TCS) surface-modified Zr-NDC was developed, providing a strong impetus for oral 5-FU delivery. The most favorable interaction sites between 5-FU and Zr-NDC were explored by computer simulation. Then, the physicochemical properties of TCS-MOF, such as particle size, size distribution, and morphology, were evaluated. Through a series of experiments, including in vitro drug release experiments, MTT analysis, and in situ single small intestinal perfusion (SPIP), the results showed that under the protection of TCS-MOF, the release rate (2.3%) of 5-FU in an acidic environment was far lower than in artificial intestinal juice (60%). The coating of TCS on the surface of Zr-NDC has the effect of controlling drug release. TCS coating can enhance the acid resistance limit of MOF and further increase the adhesion and permeability of 5-FU to the intestinal mucosa. It is expected that TCS-MOF@5-FU can serve as a potential drug delivery system for oral 5-FU.

Room-Temperature Complete Oxidation of Formaldehyde over Lactic Acid-Modified HZSM-5-Supported Pt Catalyst

Tongtong Zhang,Sijia Wang,Xingyuan Li,Yupeng Du,Jiajun Hu,Shi Jiang,Yu Guo

Room-temperature complete oxidation of formaldehyde (HCHO) is an important orientation of research programs, yet challenges remain. The development of efficient catalysts with high activity and excellent stability is of great significance for such practical application. Inspired by this whole catalytic process, we, therefore, chose HZSM-5 zeolite with abundant acidic sites as catalyst support and lactic acid (LA) as modifier to regulate the properties. The use of LA simultaneously enhances the hydroxyls density and increases the dispersion of Pt nanoparticles, which are better than the reference catalyst prepared via direct wetness impregnation method. Most satisfying of all, the lactic acid-modified HZSM-5-supported Pt catalyst demonstrates a remarkable reaction performance for room-temperature HCHO oxidation at a high concentration HCHO of 80 ppm and a large space velocity of 360,000 mL/g/h (especially with a low Pt loading of 0.5%). In addition, a 120 h test further confirms the favorable stability of the designed catalyst. This pre-modified strategy using organic acid might provide potential approach in the construction of efficient zeolite-supported catalysts.

Enhanced anticancer efficacy and tumor targeting through folate-PEG modified nanoliposome loaded with 5-fluorouracil

Van Minh Le,Trung Duc Tran Nho,Hai Trieu Ly,Thanh Sang Vo,Hoang Dung Nguyen,Thi Thu Huong Phung,Aihua Zou,Jianwen Liu

Cancer targeted therapies have attracted considerable attention over the past year. Recently, 5-fluouracil (5-FU), which has high toxicity to normal cells and short half-life associated with rapid metabolism, is one of the most commonly used therapies in the treatment of cancer. In this study the folic acid-conjugated pegylated nanoliposomes were synthesized and then loaded into them with 5-FU to improve the anti-tumor efficacy. The average size of liposomes (LPs) was about 52.7 nm which was identified by TEM. In the liposome uptake studies, the level uptake of folate-conjugated liposomes has increased compared to non-conjugated LPs according to LPs concentration, incubation time and presence of concentration of free folic acid (FA). The MTT assay and apoptotic test were carried out in HCT116 and MCF-7 cells for 24 or 48 h. The results revealed that the folate-PEG modified 5-Fu loaded nanoliposomes had strong cytotoxicity to cancer cell compared to pure 5-FU or PEG modified 5-FU loaded liposomes in a concentration- and time-dependent manner, and mainly enhanced the cancer cell death through folate-mediated endocytosis. Hence, the folate-PEG modified nanoliposome is a potential targeted drug-delivery system for the treatment of FR-positive cancers.

Pressure Reduction Enhancing the Production of 5-Hydroxymethylfurfural from Glucose in Aqueous Phase Catalysis System

Ke Ke,Hairui Ji,Xiaoning Shen,Fangong Kong,Bo Li

5-hydroxymethylfurfural (HMF) obtained from biomass is an important platform chemical for the next generation of plastics and biofuel production. Although industrialized, the high yield of HMF in aqueous systems was rarely achieved. The main problem is that HMF tends to form byproducts when co-adsorbed with water at acid sites. In this study, the pressure was reduced to improve the maximum yield of HMF from 9.3 to 35.2% (at 190 °C in 60 min) in a glucose aqueous solution. The mechanism here involved water boiling as caused by pressure reduction, which in turn promoted the desorption of HMF from the solid catalyst, thereby inhibiting the side reaction of HMF. Furthermore, the solid catalysts could be reused three times without a significant loss of their catalytic activity. Overall, this work provides an effective strategy to improve the yield of HMF in water over heterogeneous catalysts in practice.Keywords:glucose;5-hydroxylmethyfurfural;aqueous phase;heterogeneous catalysts;pressure reduction

Phosphorus promotion on hydrothermal stability of ZSM-5 by P precursors with different molecular sizes

Ne Ni,Xiuzhi Gao,Enhui Xing,Yuan Zhu,Jianqiang Liu,Mudi Xin,Ying Ouyang,Yibin Luo,Xingtian Shu

The promotional effects of phosphorous modification on ZSM-5 zeolites by phosphorus oxyacids (H 4 P 2 O 7 , H 3 PO 4 , H 3 PO 3 , and H 3 PO 2 ) with different molecular sizes were investigated with catalytic cracking of n -tetradecane as the probe reaction. It was verified that the diffusion of P precursor molecules into ZSM-5 channels was important to prevent aggregation of P species for better stabilization on tetra-coordinated framework aluminum . Meanwhile, the P–Al interaction was proposed based on results of 27 Al, 31 P, and 29 Si MAS NMR. With H 3 PO 2 as the P precursor, easy diffusion into ZSM-5 channels contributed to less formation of polyphosphates, homogeneous distribution of P species, better reserved crystallinity, microporous area and acidic sites for improving cracking performance of n -tetradecane.

Transdermal Delivery of 5-Aminolevulinic Acid by Nanoethosome Gels for Photodynamic Therapy of Hypertrophic Scars

Zheng Zhang,Ying Liu,Yunsheng Chen,Lexiang Li,Ping Lan,Dannong He,Jie Song,Yixin Zhang

5-Aminolevulinic acid (ALA)-loaded nanoethosome (ALA-ES) gels are successfully prepared to realize a transdermal delivery of ALA, and they provide a feasible approach for the photodynamic therapy (PDT) of hypertrophic scars (HS). Herein, the morphological and physicochemical features indicate that ALA-ES is stable in gel matrix. In vitro transdermal penetration studies suggest ALA-ES gels can overcome the compact dermal barrier and deliver more ALA into human HS tissue. In vivo delivery studies further reveal that ALA-ES gels can penetrate into rabbit HS tissue to facilitate ALA accumulating in hypertrophic scar fibroblast (HSF) and converting into protoporphyrin IX in the cytoplasm. Utilizing transmission electron microscopy, the visual in vivo penetration process indicates ALA-ES penetrate into HS tissue utilizing its deformable membrane, enters HSF by a pinocytotic-like mechanism, and then releases ALA in the cytoplasm. Subsequently, PDT efficacy is assessed using rabbit HS models. The morphological and histological analysis reveal that ALA-ES gels can improve HS by promoting HSF apoptosis, remodelling collagen fibers and increasing MMP3 expression. The results demonstrate that ALA-ES gels are suitable in clinical treatment of HS and make a substantial progress within the field.

Amphiphilic dendritic nanomicelle-mediated co-delivery of 5-fluorouracil and doxorubicin for enhanced therapeutic efficacy

Rui Han,Yuan Sun,Chen Kang,Huijing Sun,Wenguang Wei

Screening 5-lipoxygenase inhibitors from Choerospondias axillaris via a novel enzyme immobilization targeted fishing technology

Shiyu Li,Kai Xu,Shanpeng Ma,Xueying Qin,Li Jiang,Xiaohong Hou,Zibo Dong,Xun Gao,Lingling Huo

Currently, coronary heart disease (CHD) is prevalent worldwide, with its harmful impact second only to that of malignant tumors. A growing number of studies have confirmed that Choerospondias axillaris can significantly improve the therapeutic effect of CHD treatment and reduce the incidence of adverse reactions. However, its bioactive components and pharmacological mechanisms remain unclear. Based on a targeted fishing strategy, this study synthesized magnetic nanomaterials immobilized with 5-lipoxygenase (5-LOX) for screening and identifying 5-LOX inhibitors from the crude extract of Choerospondias axillaris . A total of 21 active components were identified and analyzed using ultra-high performance liquid chromatography-Q-Exactive Orbitrap tandem mass spectrometry (UHPLC-Q-Exactive Orbitrap-MS/MS). By comparing the screened active components with reported 5-LOX inhibitors, 9 novel 5-LOX inhibitors were discovered. Further molecular docking was performed on these 9 inhibitors, and the pharmacological activity of the selected ligands was verified using a 5-LOX inhibitor screening kit (fluorescence method).The compounds are ranked by activity from strongest to weakest: Lobetyolin (23.92 μM), Anhydroicaritin (29.55 μM), Narirutin(33.66 μM), Fisetin (47.28 μM) and Naringin(59.02 μM). This novel enzyme-immobilized targeted fishing technology is expected to efficiently and accurately screen bioactive components targeting different receptors from complex substrates.

Strategies to increase the selective electrocatalytic oxidation of 5-hydroxymethylfurfural to produce 2,5-furanedicarboxylic acid

Junxiang Wang,Xu Wang,Xiaoyan Liu,Yanfei Feng,Yukun Wan,Hui Yang

Electrocatalytic 5-hydroxymethylfurfural oxidation reaction (HMFOR) to produce 2,5-furanedicarboxylic acid (FDCA) offers a promising strategy to produce high value chemicals. Herein, CuO(S-ER-1.5) with excellent catalytic performance was prepared by anodic oxidation, sulfidation and electrochemical reconstruction on the substrate of copper foam. The experimental results of catalytic performance showed that CuO(S-ER-1.5) can catalyze HMFOR with a high current density (200 mA cm −2 ) at a low potential (1.48 V vs RHE) and exhibit outstanding stability. The open-circuit potential time test displayed that more HMF molecules were adsorbed in the Helmholtz layer of CuO(S-ER-1.5), which proved that the CuO(S-ER-1.5) could improve the kinetic adsorption of HMF. The electrochemical impedance spectroscopy further showed that CuO(S-ER-1.5) had faster reaction kinetics than Cu(OH) 2 precursor. The product analysis showed that CuO(S-ER-1.5) electrocatalytic HMFOR followed the DFF path, and the catalytic mechanism was explored by the three-step rate deconvolution procedure. It was found that CuO(S-ER-1.5) electrocatalytic HMFOR was dominated by direct oxidation reaction. This work provides a valuable guidance for the synthesis of value-added chemicals FDCA by electrocatalytic HMFOR.

Efficient conversion of glucose into 5-hydroxymethylfurfural using a bifunctional Fe3+ modified Amberlyst-15 catalyst

Siquan Xu,Chunyu Yin,Donghui Pan,Feng Hu,Yuanfeng Wu,Yanan Miao,Lijing Gao,Guomin Xiao

In this study, a series of Fe3+ modified Amberlyst-15 resins (Fe/AR) were prepared and used as environmentally friendly bifunctional catalysts for the conversion of glucose to 5-hydroxymethylfurfural (HMF). The physicochemical properties of the Fe/AR catalysts were characterized by XRD, SEM-EDX, XPS, TG-DTA and FTIR spectroscopy techniques. It was found that the 10%-Fe/AR catalyst has the ability to synergistically catalyze the isomerization of glucose and the dehydration of fructose in a “one-pot” reaction, and allows an impressive 68% HMF yield to be achieved in the H2O/THF biphasic system. Moreover, the 10%-Fe/AR catalyst still retained the desired catalytic activity after four consecutive cycles.

Gram-Scale Synthesis of Carbon-Supported Sub-5 nm PtNi Nanocrystals for Efficient Oxygen Reduction

Minli Wang,Xu Chen,Wenwen Xu,Zhongfeng Wang,Peilei He,Zhiyi Lu

The preparation of a high performance and durability with low-platinum (Pt) loading oxygen reduction catalysts remains a challenge for the practical application of fuel cells. Alloying Pt with a transition metal can greatly improve the activity and durability for oxygen reduction reaction (ORR). In this work, we present a one-pot wet-chemical strategy to controllably synthesize carbon supported sub-5 nm PtNi nanocrystals with a ~3% Pt loading. The as-prepared PtNi/C-200 catalyst with a Pt/Ni atomic ratio of 2:3 shows a high oxygen reduction activity of 0.66 A mgpt−1and outstanding durability over 10,000 potential cycles in 0.1 M KOH in a half-cell condition. The PtNi/C-200 catalyst exhibits the highest ORR activity, with an onset potential (Eonset) of 0.98 V and a half-wave potential (E1/2) of 0.84 V. The mass activity and specific activity are 3.89 times and 9.16 times those of 5% commercial Pt/C. More importantly, this strategy can be applied to the gram-scale synthesis of high-efficiency electrocatalysts. As a result, this effective synthesis strategy has a significant meaning in practical applications of full cells.

An alginate-based hydrogel composite obtained by UV radiation and its release of 5-fluorouracil

Wu Chengyi,Li Cong,Zhang Xu,Cheng Chao,Wang Jinshou

A novel pH-sensitive and macroporous NaAlg-based hydrogels were prepared, the monomers of which were N -methylolacrylamide (NMAAm) and acrylic acid, using N , N -methylene-bis-acrylamide (MBA) as a cross-linker, 2,2-dimethoxy-2-phenylacetophenone as a photoinitiator via ultraviolet irradiation. The morphology, thermal property and structure of hydrogel were characterized by Fourier transform infrared spectroscopy, scanning electron microscope, X-ray diffractometer and thermogravimetric analysis. The swelling ratios (SRs) of hydrogel were investigated in water, salt and pH solutions. The SR of hydrogel in water increased from 8.1 to 19.4 g/g with increase in weight of NaAlg from 0.2 to 1.0. The result indicated that hydrogel displayed favorable pH- and salt-sensitive. 5-fluorouracil (5-FU) as a model drug was loaded on hydrogel, the drug encapsulation efficiency of products reached to 85.2%, and the cumulative release rate of drug was 78.4 and 37% in the intestinal and gastric fluid, respectively. In addition, the dynamic data of drug release were evaluated by different mathematical models, and the experimental results revealed that it was more fitted to Ritger–Peppas and Higuchi equation models, correlation coefficients ( R 2 ) of which were up to 0.99.