Journal of Environmental Sciences
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2021
·
IF 5.565
Ji Li,Chenlu Shi,Wenbin Zeng,Yaru Wang,Zebin Hong,Yibing Ma,Liping Fang
Electron shuttles such cysteine play an important role in Fe cycle and its availability in soils, while the roles of pH and organic ligands in this process are poorly understood. Herein, the reductive dissolution process of goethite by cysteine were explored in the presence of organic ligands. Our results showed that cysteine exhibited a strong reactivity towards goethite – a typical iron minerals in paddy soils with a rate constant ranging from 0.01 to 0.1 hr −1 . However, a large portion of Fe(II) appeared to be “structural species” retained on the surface. The decline of pH was favorable to generate more Fe(II) ions and enhancing tendency of Fe(II) release to solution. The decline of generation of Fe(II) by increasing pH was likely to be caused by a lower redox potential and the nature of cysteine pH-dependent adsorption towards goethite. Interestingly, the co-existence of oxalate and citrate ligands also enhanced the rate constant of Fe(II) release from 0.09 to 0.15 hr −1 ; nevertheless, they negligibly affected the overall generation of Fe(II) in opposition to the pH effect. Further spectroscopic evidence demonstrated that two molecules of cysteine could form disulfide bonds (S-S) to generate cystine through oxidative dehydration, and subsequently, inducing electron transfer from cysteine to the structural Fe(III) on goethite; meanwhile, those organic ligands act as Fe(II) “strippers”. The findings of this work provide new insights into the understanding of the different roles of pH and organic ligands on the generation and release of Fe induced by electron shuttles in soils.
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Membranes
·
2021
·Vol. 11
·期 3
·193
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IF 4.106
Jiaming Zhang,Xiansheng Zhang,Wei Wei,Huiling Zhang,Yunfei Wang,Guoqiang Cai,Jindan Wu
Since anionic dyes and surfactants abundantly exist in oily wastewater, both the separation of oil/water mixture and removal of low-molecular-weight pollutants are important to realize the advanced purification of water. By grafting poly(2-dimethylaminoethyl methacrylate) (pDMAEMA) onto polyethylene (PP) membrane via ultraviolet (UV)-initiated polymerization, the obtained PP-g-pDMAEMA membrane presented positively in water and negatively in an alkaline buffer (pH 9.0), respectively. Due to the switchable surface charge, the membrane had high emulsion separation efficiency and flux recovery ratio (approximately 100%). Besides, the dye (reactive black 5, RB-5) adsorption capacity reached 140 mg/m2in water, and approximately 90% RB-5 could be released in pH 9.0. The anionic surfactant (sodium dodecyl benzene sulfonate, SDBS) was also reversely interpreted and released by the membrane via manipulating the ambient pH. The membrane constructed in this study is supposed to realize emulsion separation with smart cleaning capability, as well as the removal of dyes and surfactants, which could be utilized for multifunctional water purification.Keywords:oil/water separation;surface charge;antifouling;dye removal;water purification
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LWT-FOOD SCIENCE AND TECHNOLOGY
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2021
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IF 4.952
Diqiong Wang,Mingming Zhong,Yufan Sun,Lin Fang,Yuanda Sun,Baokun Qi,Yang Li
Soybean lipophilic protein (LP) is a promising emulsifier for nanoemulsion delivery systems. Herein, the influence of pH on the stability, rheological properties, and encapsulation efficiency of a nanoemulsion formed by ultrasonically modified LP was determined, and its influence mechanism was explored. The delivery system exhibited a high absolute zeta potential value (18–30 mV) in neutral and alkaline environments (pH 7.0 or 9.0) and uniform particle size distribution (100–350 nm). Cryo-scanning electron microscopy showed that LPs in neutral and alkaline environments covered the oil–water interface more evenly than those in acidic environments. Moreover, the LP nanoemulsion has excellent rheological properties and exhibit high emulsification performance, vitamin E encapsulation efficiency, and oxidation stability. These improvements occurred because the nanoemulsion prepared using ultrasonicated LP had a high absolute zeta potential value (maximum 30 mV), small droplet size (minimum 190 nm), uniform protein film , high viscosity, and good viscoelasticity in different pH environments. In summary, the nanoemulsion delivery system prepared by LP ultrasonication can resist the influence of different pH environments and maximize the delivery efficiency in neutral and alkaline environments. The research results identified a suitable pH environment for LP nanoemulsions and provide a theoretical reference for their further application.
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JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION
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2021
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IF 3.517
Jinsong Du,Lijuan Wang,Xiao Han,Jie Dou,Jiang Yuan,Jian Shen
Drug-loaded nanoparticles have been widely used in the field of tumor treatment due to their low side effects and reduced frequency of administration. In this study, pH and glutathione (GSH) dual-responsive keratin-tannic acid (TA) complex nanoparticles were established to trigger drug release under tumor microenvironments. Reductive keratin was first extracted using a reduction method. Then, keratin-TA complex nanoparticles (KNPs) were self-assembled via non-covalent interaction and further stabilized by self-crosslinking of thiols. This method was facile and green without chemicals during the whole procedure. KNPs exhibited pH and GSH dual responsiveness as well as charge reversibility in the simulated tumor microenvironment. The anticancer drug of doxorubicin (DOX) was loaded on KNPs by hydrophobicity and hydrogen bonds. Drug-loaded KNPs accelerated drug release under mimicked tumor microenvironments, performing high toxic against A549 cells while low toxic on normal cells. Besides, drug-loaded nanoparticles could be endocytosed by tumor cells. Based on these results, KNPs may serve as drug carriers for therapeutic delivery.
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BIOSENSORS & BIOELECTRONICS
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2021
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IF 10.618
Lei Chen,Yan Li,Luyang Miao,Xiaolong Pang,Tao Li,Yongjun Qian,He Li
In the field of precision medicine, the anticipated features of ideal drug delivery systems (DDS) have high drug loading capacity and effective stimuli-triggered mechanism, which are fitting well with the expected merits of signal labels for enhanced enzyme-linked immunosorbent assay (ELISA). Inspired by this, poly (diallyldimethylammonium chloride)-capped curcumin nanoparticles (PDDA@CUR NPs) with high loading capacity were synthesized as signal labels and further applied to dual-model colorimetric and fluorescence ELISA for the detection of C-reactive protein (CRP). Curcumin (CUR) was elaborately selected as report molecule similar to the roles of drugs in DDS, which dispersed in neutral water exhibits a negligible fluorescence response due to the aggregation of CUR molecules induced quenching effect, stimulated by basic water (BW, pH 12.36), the allochroic effect from colorless to orange occurred and fluorescence restored because of the keto–enol tautomerism in the molecular structure of CUR, just like lighting-up (from signal “OFF” to signal “ON”), yielded a dual-model colorimetric and fluorescent signal readout. PDDA, as a polycationic electrolyte, provided a biological platform that is capable of interacting with CRP label antibodies by virtue of its positive centers. The results show that “lighting-up” CUR NPs-based dual-modal colorimetric and fluorescent ELISA for CRP detection has the merits of easy-to-use, good enough sensitivity and reliability. And more importantly, it brings innovative ideas for the precise identification and quantification of protein biomarkers.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2021
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IF 6.953
Mengyao Zhang,Gang Chen,Mengheng Lei,Jiaqing Lei,Dan Li,Hua Zheng
Delayed healing or non-healing of wounds caused by bacterial infection is still a difficult medical problem. Nowadays, the topical application of antibiotics is a common treatment for infections. However, subinhibitory concentrations or high dose of antibiotics leads to the antibacterial effect counterproductive. So it's necessary to put forward an on-demand drug delivery to solve this tough issue. In this paper, a pH-responsive hydrogel was prepared by oxidized dextran (Dex-CHO), sulfadiazine (SD) and tobramycin (TOB). The hydrogel was designed by the environment in the early immature stage of biofilm (pH 5.0). Schiff bases can release drugs in slightly acidic environment. The hydrogel showed injectable, pH-sensitive drug release, and great biocompatibility. Released SD and TOB exhibited a synergistic effect therefore the hydrogel showed high antibacterial activity . This study provides an easy and promising strategy to develop smart hydrogels that aim at topical administration of antibiotics and come up with a new treatment of local bacterial infections.
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MACROMOLECULAR BIOSCIENCE
·
2021
·Vol. 21
·期 5
·2100025
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IF 4.979
Qinping Yang,Yanliang Dong,Xuanyu Wang,Zhihao Lin,Mingyu Yan,Weiwei Wang,Anjie Dong,Jianhua Zhang,Pingsheng Huang,Changrong Wang
pH-sensitive polyelectrolytes provide enormous opportunity for siRNA delivery. Especially, their tertiary amine structures can not only bind genes but also act as pH-sensitive hydrophobic structure to control genes release. However, the influence of molecular structures on siRNA delivery still remains elusive, especially for the asymmetric alkyl substituents of the tertiary amine groups. Herein, a library of N -methyl- N -alkyl aminoethyl methacrylate monomers (MsAM) with asymmetric alkyl substituents on the tertiary amine group is synthesized and used to prepare a series of tri-block polycationic copolymers poly(aminoethyl methacrylate)-block-poly ( N -methyl- N -alkyl aminoethyl methacrylate)-block-poly(ethylene glycol methacrylate) (PAMA-PMsMA-PEG). And the properties of these polycations and their self-assembled micelles are characterized, including molecular structure, proton buffering capacity, pH-sensitivity, size, and zeta potential. With the length increase of one alkyl substituent, the proton buffering capacity of both monomers and polycations is demonstrated to be narrowed down. The siRNA delivery efficiency and cytotoxicity of these micelles are also evaluated on HepG2 cells. In particular, poly(aminoethyl methacrylate)-block-poly( N -methyl- N -ethyl aminoethyl methacrylate)-block-poly(ethylene glycol methacrylate) (PAMA-PMEMA-PEG) elicited the best luciferase knockdown efficiency and low cytotoxicity. Besides, PAMA-PMEMA-PEG/siRRM2 also induced significant anti-tumor activity in vitro. These results indicated PAMA-PMEMA-PEG has potential for further use in the design of gene vehicles with the improved efficiency of siRNA delivery.
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APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY
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2021
·Vol. 193
·期 10
·3062-3078
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IF 2.926
Wei Yanli,Chen Xi,Yang Ting,Wan Junfen,Cao Xuejun
Aqueous two-phase systems (ATPS) have the advantages of environmentally friendly, high mass transfer efficiency, and mild extraction conditions. However, it is difficult to recycle these polymers, which limits the large-scale application of ATPS. In this study, a novel recyclable ATPS was constructed with thermo-responsive polymer P N and pH-responsive polymer P ADB4.78 for the partition of tea saponin. P N represents poly-( N -isopropylacrylamide), and P ADB4.78 represents poly-(acrylic acid-dimethylamine ethyl methacrylate-butyl methacrylate), where 4.78 in the subscript indicate the isoelectric point of the polymer. The recoveries of P N and P ADB4.78 were 95.36% and 93.48%, respectively, after two cycles. Meanwhile, the phase formation mechanism of ATPS was studied by surface tension and low-field nuclear magnetic resonance (LF-NMR). The effects of polymer concentration, pH, temperature, types and concentrations of salt were investigated on tea saponin partition. In the 1.5% (w/v) P N /3.5% (w/v) P ADB4.78 ATPS, the optimal partition coefficient ( K ) of crude tea saponin were 0.15 in the presence of 1.5 mM KCl at pH 7.6 and 25 °C while the extraction recovery (ER b ) reached 92.13%. The K and ER b of tea saponin from tea seeds were 0.12 and 94.50% with 7.5 mM LiBr at pH 8.0 and 25 °C, respectively.
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PROPELLANTS EXPLOSIVES PYROTECHNICS
·
2021
·Vol. 46
·期 5
·690-696
·
IF 1.887
Naimeng Song,Li Yang,Pingan Liu
This paper mainly introduces the Ph−Fe/RDX(HMX) composite microspheres prepared by ultrasonic spray drying. Their morphology was observed by SEM and found that the composite microspheres were spherical. Also, the composite microspheres exhibited good dispersion. The results of the granularity data show that the D 50 data of Ph−Fe/RDX and Ph−Fe/HMX were 580.78 nm and 496.52 nm, respectively. The DSC data showed that the catalytic effect of the composite microspheres was significantly better than that of the mixed powder. The DSC data showed that the decomposition peak temperature of the Ph−Fe/RDX(HMX) composite microsphere was 229.6 °C (279.6) lower than the 235.6 °C (284.3) of the mixed powder. The DSC data demonstrated that the catalytic performance of the composite microspheres was significantly better than that of the mixed powder. Therefore, the ultrasonic spray drying method has great potential for preparing energetic composite microspheres.
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POLYMER
·
2021
·
IF 4.43
Xiaotao Wang,Yebin Yang,Chuang Liu,Huiling Guo,Zhuofan Chen,Junyong Xia,Yonggui Liao,Chak-Yin Tang,Wing-Cheung Law
A near infrared (NIR) and pH dual-responsive nanocomposite, composed of a lanthanide-doped upconversion nanoparticle (UCNP) core and a transformable poly- o -nitrobenzyl shell, was prepared by the distillation precipitation polymerization and template method. The poly- o -nitrobenzyl shell can undergo hydrophobic-hydrophilic transformation upon an irradiation of 980 nm, rendering the capability of NIR-activated drug release. The anticancer drug , doxorubicin (DOX), can be loaded into these nanocomposites with a loading efficiency of 7.23 wt%. Furthermore, pH responsiveness caused by the hydrogen bond and charge interactions between DOX and nanocapsules can trigger the release of drugs at low pH. Under visible light irradiation and neutral (pH 7.4) conditions, the cumulative release of DOX was only 8.35% after 300 min, while it reached 59.5% under the synergistic effect of NIR irradiation and acidic conditions. The Baker-Lonsdale model was used to describe the drug release kinetics of this system, and the diffusion coefficient (3 DC s / r 0 2 C 0 ) and R 2 under different conditions were determined to be 4.15 × 10 −6 and 0.98 (pH 7.4 and visible light), 2.64 × 10 −5 and 0.99 (NIR light), 3.26 × 10 −5 and 0.97 (pH 4.5 and visible light), 2.59 × 10 −4 and 0.99 (pH 4.5 and NIR light), respectively. This controlled release feature makes the nanocomposite a promising therapeutic agent for treating diseases.
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LANGMUIR
·
2021
·
IF 3.882
Yingying Chai,Yuefei Wang,Bingqi Li,Wei Qi,Rongxin Su,Zhimin He
In this work, lignin/chitosan nanoparticles (Lig/Chi NPs) with controlled structures were synthesized in a simple and scalable microfluidic system. When the positively charged chitosan and the negatively charged lignin solution were blended in a microreactor, Lig/Chi NPs were rapidly formed via the electrostatic coassembly between the amino groups of chitosan and the carboxyl groups of lignin. The ζ potential changes from negative (−13 mV) to positive (+54.5 mV) for Lig NPs and Lig/Chi NPs, respectively. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results demonstrated that Lig/Chi NPs have an average particle size of about 180 nm, which can be used as nanocarriers for drug delivery. The anticancer drug nanoparticles with docetaxel (DTX) and curcumin (CCM) were prepared by coassembly with Lig/Chi NPs in a microreactor, which had good drug loading efficiency, biocompatibility, and can release drugs in response to pH in the weakly acidic environment of the tumor. The drug release amounts in acidic solutions that simulated the tumor microenvironment were 51% (DTX@Lig/Chi NPs) and 50% (CCM@Lig/Chi NPs), respectively, which were better than the release amounts at pH 7.4, and have an obvious killing effect on HeLa cells.
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CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Wei Jin,Hengbo Wu,Weiquan Cai,Baohua Jia,Munkhbayar Batmunkh,Zexing Wu,Tianyi Ma
Designing highly-efficient and pH-universal electrocatalysts for overall water-splitting reactions is important for the sustainable production of hydrogen. Herein, NiRu nanoparticles encapsulated into N-doped carbon (NiRu@NC) are fabricated with the assistance of MOF for hydrogen evolution reaction (HER) and also evolved into core–shell structured nanomaterials with abundant interfaces for oxygen evolution reaction (OER, Ni/RuOx@C). Benefiting from optimized electronic structure, interfacial synergy effect and special core–shell structure (~150 nm), the newly developed electrocatalysts present remarkable electrocatalytic activities with small overpotentials to drive 10 mA cm −2 for the HER (19 mV in alkaline, 80 mV in neutral, 20 mV in acid) and OER (252 mV, 316 mV, 211 mV). Moreover, the obtained electrocatalysts exhibit outstanding catalytic performances for overall water-splitting in a two-electrode system with 1.53 V and 1.67 V to drive 10 mA cm −2 in basic and neutral electrolyte, respectively. Remarkably, a small potential of 1.47 V is required to deliver 10 mA cm −2 in acidic media and no significant decay of the activity is observed. This work paves the way for designing a novel class of electrocatalyst that can not only exhibit remarkable electrocatalytic water splitting performances in various conditions, but also possess excellent stabilities for future generation of clean energy.
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