查找使用阿拉丁产品的科研文献

Novel bagasse cellulose-based foams with pH-responsive wetting properties for controlled oil/water separation

Mengling Xie,Mingqiang Zhong,Chenni Qin,Yang Liu,Hui Zhao,Wenbo Yin

In this study, bagasse cellulose-based porous foams were developed using bleached sugarcane bagasse pulp as the main raw material. The intention was to achieve controlled oil/water separation using low-cost and environmentally acceptable raw materials to solve the current problem of oily wastewater treatment . Bagasse cellulose-based foams with 3D structure and good mechanical properties were produced via freeze-drying. A pH-responsive copolymer was synthesized by free radical polymerization to modify the foam with pH-responsive wettability. Results showed that bagasse cellulose-based foams with an adsorption capacity of up to 48.77 g/g, and their pH-responsive properties could easily achieve the wettability transition between super-oleophilic (oil contact angle is 0°) and super-oleophobic (oil contact angle is 157.3°). The changes in foam wettability were realized by the conformational transition of pH-responsive copolymers under different pH values. Ultimately, the pH-responsive switchable wettability of the foam was still able to reach 80% adsorption capacity after five cycles, demonstrating excellent stability and recyclability.

A pH-responsive complex based on supramolecular organic framework for drug-resistant breast cancer therapy

Yun-Chang Zhang,Pei-Yu Zeng,Zhi-Qiang Ma,Zi-Yue Xu,Ze-Kun Wang,Beibei Guo,Feng Yang,Zhan-Ting Li

Thermal, structural, and emulsifying properties of pumpkin seed protein isolate subjected to pH-shifting treatment

Gao Dan,Helikh Anna,Duan Zhenhua,Xie Qingli

In this study, the thermal, structural, and emulsifying properties of pumpkin seed protein isolates (PSPI) subjected to pH-shifting were investigated. PSPI subjected to different pH values (pH 2, 4, 6, 8, 10, and 12), were named PSPI 2, PSPI 4, PSPI 6, PSPI 8, PSPI 10, and PSPI 12, respectively. According to the differential scanning calorimetry analysis, the control PSPI exhibited denaturation temperatures of 87.67 and 104.11 °C, and their corresponding enthalpies were 1.66 and 0.37 J/g, respectively. Among the PSPI samples, only PSPI 2 showed no significant difference in denaturation temperatures and enthalpies as compared to the control PSPI. The emulsifying activity indexes of PSPI 2, PSPI 4, and PSPI 12 increased ( p  > 0.05) by 205.84, 298.98, and 288.69%, respectively, and the emulsion stability indexes of these three samples increased by 42.32, 67.58, and 40.87%, respectively. The disulfide bond contents of PSPI 2, PSPI 4, and PSPI 12 increased by 7.46, 9.28, and 5.01%, respectively, and the free sulfhydryl group contents of these three samples decreased by 36.69, 44.39, and 29.11%, respectively, which indicated that the improved emulsifying properties of PSPI 2, PSPI 4, and PSPI 12 might be correlated to the increased disulfide bond contents and decreased free sulfhydryl group contents. However, the emulsifying properties of PSPI samples had no obvious correlation with their surface hydrophobicity and particle sizes.

A Near-Infrared Triggered Intracellular pH Regulative PAMAM/O-nitrobenzaldehyde Coated UCNPs for Cancer Therapy

Liping Zhou,Hao Hu,Yi-Xin Zhang,Qing-Ye Meng,Bing Yu,You-Qing Shen,Hai-Lin Cong

Dendrimers have become effective drug carriers and gene transfection vectors for medical biomaterials. In this experiment, UCNPs (NaGdF4:Tm, Yb@NaGdF4) and three-generation PAMAM dendrimers were prepared firstly; then NaGdF4:Tm, Yb@NaGdF4 was modified by Polyacrylic acid(PAA); PAMAM were grafted to the surface of the modified UCNPs by the reaction between amino groups and carboxyl groups; finally, O-nitrobenzaldehyde was grafted to the surface by Schiff base reaction.The synthesized upconversion materials were coated with PAA and PAMAM, then loaded with O-nitrobenzaldehyde to form spherical nanoparticles. The particle size of prepared nanoparticles is 75 ∼ 80 nm. The dendrimer complex can emit ultraviolet light to regulate the pH gradient of aqueous solution under the excitation of near-infrared light (980 nm), and can be used to kill cancer cells by changing the acidity of tissue cells; secondly, the cavity between dendrimers and dendrimers on the surface of the complex can be used in many fields such as drug delivery and gene transfection; the nanoparticles provide a new method for cancer treatment.

Insights on the pH-dependent roles of peroxymonosulfate and chlorine ions in phenol oxidative transformation

Chen-Xuan Li,Chang-Bin Chen,Yun-Jie Wang,Xian-Zhong Fu,Shuo Cui,Jia-Yuan Lu,Jie Li,Hou-Qi Liu,Wen-Wei Li,Tai-Chu Lau

The formation of halogenated disinfection byproducts (DBPs) during organic pollutants degradation in advanced oxidation processes (AOPs) has raised growing concerns globally. However, the detailed roles of chlorine ions (Cl − ) in pollutant degradation by peroxymonosulfate (PMS) alone remain controversial so far. Here, we shed light on the PMS-Cl − -phenol interactions and revealed a previously overlooked pH-dependent phenol transformation pathway. At acidic pH, Cl − significantly accelerated the phenol removal. The Cl − -PMS reaction resulted in abundant reactive chlorine species, which attacked phenol to form 4-chlorophenol and 2, 4-dichlorophenol as the main transformation products. In contrast, the impact of Cl − became negligible at alkaline pH. Raising the pH severely suppressed the phenol chlorination and significantly stimulated generation of singlet oxygen ( 1 O 2 ) for degradation of phenol and the minor formed chlorophenols. The 1 O 2 was resulted from a combined effect of PMS self-decomposition and PMS-benzoquinone interaction at alkaline pH. Our results imply a previously-underestimated impact of Cl − on phenolic compounds degradation in PMS-based AOPs and underscore a potential risk of chlorinated DBPs formation under environmental conditions.

Super-pH-Sensitive Mesoporous Silica Nanoparticle-Based Drug Delivery System for Effective Combination Cancer Therapy

Yin-Jia Cheng,Si-Yong Qin,Yi-Han Ma,Xiao-Sui Chen,Ai-Qing Zhang,Xian-Zheng Zhang

A multifunctional nanoplatform based on mesoporous silica nanoparticles (MSNs) was developed for combinational tumor therapy. Doxorubicin (DOX) was chosen as an antitumor drug and loaded into mesopores of MSNs via physical absorption. Then, a tumor-targeted fusion peptide conjugated with 2,3-dimethylmaleic anhydride (DTCPP) and a therapeutic peptide conjugated with 2,3-dimethylmaleic anhydride (DTPP) were introduced to the surface of MSNs as super-pH-sensitive nanovalves through disulfide linkages. The BSA adsorption assay confirmed the charge-reversal property of MSN-ss-DTPP&DTCPP nanoparticles at slightly acidic condition (pH 6.8) and superior stability in physiological environment (pH 7.4). According to the drug release research, both glutathione (GSH) and acidic condition are required for the accelerated drug release from DOX@MSN-ss-DTPP&DTCPP nanoparticles. Moreover, in vitro studies demonstrated the significantly reinforced tumor cellular uptake efficiency and mitochondrial disruption ability of DOX@MSN-ss-DTPP&DTCPP nanoparticles in tumor environment, in which DOX@MSN-ss-DTPP&DTCPP nanoparticles exhibited the preferred cytotoxicity toward αvβ3-positive human cervical carcinoma (HeLa) cells. We believe that the multifunctional dual-stimuli-sensitive MSN could provide an effective strategy for combinational tumor therapy.

An exceptionally stable Zr-based fluorescent metal–organic framework for highly selective detection of pH

Shun-Hua Wu,Shu Wang,Wen-Le Fang,Xiao-Feng Guo,Hong Wang

In this study, we synthesized metal–organic frameworks (MOFs) UiO-67-bpydc using H2bpydc as ligands and Zr6 clusters as vertexes. Due to the protonation of the bipyridine group, UiO-67-bpydc shows pH-dependent fluorescence (365 nm/530 nm) in the pH range from 1 to 9, which shows its feasibility as a wide-range pH sensor. Further study indicated that UiO-67-bpydc exhibits stability, reusability, selectivity and has an excellent linear relationship in the pH range 4.0–6.5, and the mechanism of the UiO-67-bpydc fluorescence intensity with the variation of pH has been studied in detail. This MOF-based fluorescent sensor has been applied to specifically detect the pH of solutions in the presence of the body fluid matrix. Compared with reported pH-MOF sensors, UiO-67-bpydc can be practically applied in real samples and is easily prepared with excellent stability in different buffer solutions.

ZnO Quantum Dots Modified by pH-Activated Charge-Reversal Polymer for Tumor Targeted Drug Delivery

Yifan Wang,Liang He,Bing Yu,Yang Chen,Youqing Shen,Hailin Cong

In this paper, we reported a pH responsive nano drug delivery system (NDDS) based on ZnO quantum dots (QDs) for controlled release of drugs. Zwitterionic poly(carboxybetaine methacrylate) (PCBMA) and poly(2-(dimethylamino) ethyl methacrylate) (PDMAEMA) were introduced to modify ZnO QDs, which can help enhance water stability, increase blood circulation time, and promote endocytosis. After tuning of PCBMA/PDMAEMA ratios, the ZnO@P(CBMA-co-DMAEMA) nanoplatform shows a sensitive switch from strong protein adsorption resistance (with negatively charged surface) at physiological pH to strong adhesion to tumor cell membranes (with positively charged surface) at the slightly acidic extracellular pH of tumors. Anti-cancer drug, Doxorubicin (DOX), molecules were demonstrated to be successfully loaded to ZnO@P(CBMA-co-DMAEMA) with a relatively large drug loading content (24.6%). In addition, ZnO@P(CBMA-co-DMAEMA) loaded with DOX can achieve lysosomal acid degradation and release of DOX after endocytosis by tumor cells, resulting in synergistic treatment of cancer, which is attributed to a combination of the anticancer effect of Zn2+and DOX.Keywords:Zinc oxide quantum dots (ZnO QDs);poly(carboxybetaine methacry late) (PCBMA);poly(2-(dimethylamino) ethyl methacrylate) (PDMAEMA);drug delivery

Synergistic pH and Temperature-Driven Actuation of Poly(NIPAM-co-DMAPMA)/Clay Nanocomposite Hydrogel Bilayers

Guorong Gao,Liufang Wang,Yang Cong,Zhenwu Wang,Yang Zhou,Rong Wang,Jing Chen,Jun Fu

Hydrogel actuators that deform in response to external stimuli have promising applications in diverse fields. It is desirable to develop robust hydrogels with multiple and synergistic stimuli responsiveness. This work reports on robust poly(NIPAM-co-DMAPMA)/clay hydrogel bilayers that undergo reversible and repeatable curling/uncurling in response to pH and/or temperature changes. The bilayers are fabricated by sequential synthesis of thermoresponsive N-isopropylacrylamide (NIPAM) and N-[3-(dimethylamino)propyl] methacrylamide (DMAPMA) monomers, which produces robust interface bonding between the layers. Different NIPAM/DMAPMA ratios were used between two gel layers to manipulate the asymmetric responsiveness, thus leading to curling/uncurling of bilayers upon exposure to stimuli. The hydrogel bilayers are fabricated into soft manipulators to grasp and release target objects by pH and temperature changes, and as artificial muscle to lift and move a hanging weight by synergistic pH and temperature stimuli. This work provides a new type of asymmetric responsive hydrogel bilayer with potential applications in biomimetic actuators.

Partitioning of tylosin in recyclable aqueous two-phase systems based on two pH-responsive polymers

Shan Bai,JunFen Wan,XueJun Cao

Aqueous two-phase systems (ATPS) are a promising biotechnology in bioseparation. However, recycling of the phase-forming polymer is a key issue. In this research, new recyclable ATPS composed of two pH-responsive polymers (P ADB4.01 and P MDBH3.27 ) were prepared. The ATPS could be recycled by adjusting the pH of the solution, with recovery of 93.8%. The ATPS were evaluated for the first time in the partitioning of tylosin. The effects of the main parameters, such as the polymer concentration, pH, temperature, salt species and concentrations, on the partition of crude tylosin and tylosin from fermentation broth were studied. In the 2% P MDBH3.27 /3% P ADB4.01 ATPS, the partition coefficient (K) and extraction recovery (ER top ) of crude tylosin could reach 5.12 and 93.9%, respectively, in the presence of 90 mM KCl at pH 5.83 and 25 °C. In the 2.5% P MDBH3.27 /3% P ADB4.01 ATPS, the K and ER top of tylosin from fermentation broth reached 3.58 and 87.3%, respectively, in the presence of 20 mM KBr at pH 5.69 and 25 °C. Through partition mechanism analysis by Fourier transform infrared spectroscopy (FT-IR) and interphase potential measurements, the appearance of a new absorption peak and interphase potential difference, respectively, may contribute to the partitioning of tylosin in the P ADB4.01 -enriched top phase.

GSH/pH dual-responsive biodegradable camptothecin polymeric prodrugs combined with doxorubicin for synergistic anticancer efficiency

Jun Li,Zu-E. Hu,Xian-Ling Yang,Wan-Xia Wu,Xiu Xing,Bo Gu,Yan-Hong Liu,Na Wang,Xiao-Qi Yu

Dual stimuli-responsive camptothecin polymeric prodrugs (CPT Prodrugs) with grafted structures were designed via chemoenzymatic methods and combined with doxorubicin (DOX) for synergistic drug delivery to improve anticancer efficiency. The CPT Prodrugs loaded DOX with a high efficiency through the cooperative contribution of several interaction forces. The produced amphiphilic polymeric prodrugs loaded with DOX, referred to as DOX@CPT Prodrugs, formed homogeneous spherical micelles of appropriate sizes (sub-50 nm). The DOX@CPT Prodrug micelles showed excellent stability in release experiments under in vitro physiological conditions and maintained over 80% drug loading after 4 weeks when stored at 4 °C. Under weakly acidic pH and reduced glutathione (GSH) conditions, the DOX@CPT Prodrugs with high disulfide and tertiary amine content achieved synergistic release of the two loaded drugs and biodegraded into low-molecular-weight compounds. The cell experiments confirmed that the internalization of DOX@CPT Prodrugs into cancer cells was greatly improved by nearly 30% compared with that of free drugs. Furthermore, the synergistic drug delivery system exhibited superior anticancer efficiency with highly improved cell selectivity ratios (up to 127.0%) and greatly enhanced synergistic effects (up to 23.9%) benefiting from good long-term stability, better internalization by cells and sensitive pH and GSH dual-responsivity. In addition, the DOX@CPT Prodrugs with suitable sizes and good water solubility also exhibited a greater penetrability in the case of simulating solid tumors than the free drugs. These results demonstrate the potential of DOX@CPT Prodrugs as biodegradable, dual-responsive combination therapy nanocarriers for synergistic anticancer treatment.

pH-responsive composite micro-capsule as an efficient intestinal-specific oral delivery system for lactoferrin

Yun-shan Wei,Kun Feng,Min-hua Zong,Hong Wu

To improve the bioavailability of lactoferrin (Lf) and achieve its controlled release in the intestinal tract, a pH-responsive composite system for the oral delivery of Lf was successfully developed for the first time. The negatively charged poly(lactide-co-glycolide) (PLGA)/poly(styrene-co-4-styrene-sulfonate) (PSS) nanoparticles (NPs) were firstly prepared by solvent displacement, and the resulting NPs were spherical in shape with diameter of around 120 nm and zeta potential of −50.7 mV. Then, the positively charged Lf was incubated with PLGA/PSS NPs followed by coating with pectin to improve the Lf adsorption efficiency. The Lf adsorption efficiency decreased with the increase of Lf concentration, but it was even as high as 80.5% when Lf concentration was 8.0 mg/mL. The pectin coated Lf-PLGA/PSS NPs were further incorporated into Eudragit S-100 (ES-100) micro-capsule by the self-assembly method and the obtained composite ES-100 micro-capsule was found to be spherical with an average diameter of 2.22  μ m. The in vitro release experiment showed that only a little Lf (<1%) was released from micro-capsule in simulated gastric fluid comparing with that of pectin coated Lf-PLGA/PSS NPs (30%), and around 82% Lf was released into the simulated intestinal tract in the following 8 h. The results of cytotoxicity test suggested that there was negligible toxicity of the composite micro-capsule against Caco-2  cells. The SDS-PAGE and CD spectrum analysis indicated that the micro-encapsulated Lf retained the integrity of its primary and secondary structure during the heating treatment process. Hence, the obtained Lf-loaded composite micro-capsule is promising in the oral delivery of Lf.