SENSORS AND ACTUATORS B-CHEMICAL
·
2021
·
IF 7.46
Ying Zhang,Qian Liu,Mengting Liu,Xueni Zhang,Xiaoya Li,Lihui Dai,Meng Meng,Dingbin Liu,Yongmei Yin,Rimo Xi
The microenvironment of lysosomes plays an important role in various functions within cells. Abnormal pH changes in lysosomes account for multiple diseases including tumors. Acid-responsive nanomaterials with reconfigurable structures and properties have garnered significant interests. Owing to the potential in biosensing, controlled release and nanomachinery, DNA based pH-responsiveness has been widely pursued. Herein, we designed an AuNPs-i-motifs based SERS probe to monitor the pH dynamics of lysosomal maturation in different cells. Taking advantages of biocompatibility and structural flexibility of DNA, unique optical and plasmonic properties of gold nanoparticles , excellent stability and enhanced sensitivity of background-free Raman reporter, the designed SERS probe could indicate the pH variation dynamically in lysosomes. What is more valuable is that 4-mercaptobenzonitrile is not only used as a Raman reporter to provide sensitive Raman signal for pH sensing, but also used as a sealing agent allowing for controllable aggregation, to improve the stability and accuracy of the sensor. With this versatile design, the sensor was prepared simply and feasibly and a tedious trial was avoided. It provides a feasible tool for understanding the relationship of lysosomal pH with fundamental cellular functions and mechanism of diseases.
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2021
·Vol. 28
·期 26
·35113-35125
·
IF 4.223
An Shaorong,Jin Qiang
In recent years, the excess discharge of ammonia nitrogen from wastewater into surface water has been regulated by more stringent standard. The air stripping method is successfully used to treatment of high-concentration ammonia nitrogen; however, alkali will be added to keep pH more than 10, which is costly and not environment-friendly operation. In this study, an advanced air stripping (AAS) based on foam separation of removing ammonia nitrogen in low concentration from aqueous solution at low pH was proposed. The effect of conditions such as air flow rate, temperature, SDS dosage, coexisting ionic strength, pH, and initial ammonia nitrogen concentration on the removal efficiency was studied. The advanced air stripping exhibited favorable removal efficiency for NH 4 + -N in low concentration from aqueous solution (20 mg·L −1 ) with a broad range of low pH 3.0–9.0. Besides, for strongly alkaline (pH=11.0) solution, the advanced air stripping can alleviate the decrease of pH to some extent and keep ammonia nitrogen stripping out continuously based on equilibrium shift between NH 4 + and NH 3 . A microcalorimeter was applied to demonstrate the interaction between the negatively charged hydrophilic groups of SDS and NH 4 + ions, helping to understand the mechanisms more clearly. The simple operation and the satisfactory removal efficiency could imply that the advanced air stripping is a promising technology for minimizing low-concentration NH 4 + -N. Graphical abstract
✓ 已验证
产品关联
DOI
PubMed
高影响因子
DYES AND PIGMENTS
·
2021
·
IF 4.889
Jianqiang Song,Ning Zhao,Yuan Qu,Longshan Zhao
A novel green pH-sensitive fluorescent probe based on the surface passivation was designed for sensitive, rapid and reliable detection of pirimicarb (PRC). Using natural deep eutectic solvent (NADES) as the green precursor, N-CDs were hydrothermally synthesized, and combined with rhodamine B (RhB) to display strong fluorescence emission peaks at 400 and 582 nm, respectively. Upon the addition of PRC, the fluorescence sensor resulted in the enhanced fluorescence at 400 nm, while the orange signals hardly changed. Moreover, under the optimal conditions, the proposed assay exhibited super-fast, high selectivity and sensitivity for PRC with a wide linear range from 0.5 to 200 μg mL −1 and the relatively low detection limit around 0.3 μg mL −1 . Importantly, real sample analyses demonstrated that the as-presented sensor had excellent potential in pesticide monitoring. Meanwhile, the enhanced photoluminescence that become emissive upon stability from N-CDs was attributed to the reduction of surface defects after the surface passivation. In virtue of superior biocompatibility, excellent optical properties and low toxicity, the N-CDs were further employed to monitor the pH value.
✓ 已验证
产品关联
DOI
高影响因子
ACS Catalysis
·
2021
·
IF 13.084
Jiayi Qin,Cong Xi,Rui Zhang,Tao Liu,Peichao Zou,Deyao Wu,Qianjin Guo,Jing Mao,Huolin Xin,Jing Yang
It is highly desirable to develop all-pH-compatible hydrogen evolution reaction (HER) electrocatalysts that can be used universally in a variety of different electrolyzers and operated in different pH conditions, i.e., acid, alkaline, microbial, chlor-alkali, etc. So far, two-dimensional layered MoS2 and Mo-based carbon materials have been regarded as promising pH-universal HER electrocatalysts. 2H-MoS2 as a naturally occurring and thermodynamically favorable phase, yet still suffers from poor HER activity in neutral and alkaline electrolytes. Herein, a hybrid electrocatalyst, i.e., 2H-MoS2/N-doped mesoporous graphene, rich in interfacial Mo–pyridinic N coordination is fabricated. The optimized hybrid catalyst delivers long-term durability and outstanding HER activity with overpotentials of 110, 145, and 142 mV at 10 mA cm–2 in acidic, alkaline, and phosphate buffered solutions (PBS) media, respectively, outperforming most of the previously reported MoS2-based catalysts. Theoretical and experimental results demonstrate that the interfacial pyridinic N has a higher tendency to bond with Mo atoms than pyrrolic and graphitic N, and the edge-Mo coordinated with pyridinic N could serve as HER active sites. DFT calculations further reveal that Mo–pyridinic N coordination modifies the charge density of edge-Mo, in turn optimizing the hydrogen absorption energy and facilitating water dissociation, and thereby significantly promoting the intrinsic catalytic activity for the pH-universal HER process.
✓ 已验证
产品关联
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2021
·
IF 8.198
Mengya Mu,Yingzhan Li,Hou-Yong Yu,Ziheng Li,Yiwen Cao,Xinyi Chen
Although chemical cross-linking could greatly improve the mechanical flexibility of nanocellulose aerogels, current cross-linking strategies still have some shortcomings, such as a complex cross-linking process or toxic cross-linking agents. Herein, a copolymer (PDMAEMA-co-PVTMS) containing polyorganosiloxane and a pH-responsive segment was designed and synthesized via free-radical polymerization. The polyorganosiloxane could covalently cross-link to a cellulose nanofiber (CNF) and the dimethylaminoethyl methacrylate (DMAEMA) section could endow the aerogel with pH-responsive properties. The prepared aerogel showed a three-dimensional (3D) porous structure with a specific surface area as high as 53.88 m2/g. Furthermore, the cross-linked aerogel had excellent mechanical flexibility and its maximum stress could be maintained above 71.3% of the initial value (11.88 kPa) after 50 cycles. More importantly, the aerogel could turn from a positive charge to a negative charge when the environment changed from acidity to alkalinity. It could be used to adsorb bovine serum albumin (BSA) in an acidic environment and adsorption capacity could reach 107 mg/g. It also could release 97% of adsorbed BSA in an alkaline environment. This work provided a new strategy to construct functional cellulose aerogels with excellent mechanical properties through structural design of a cross-linking agent containing organosiloxane.
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES B-BIOINTERFACES
·
2021
·
IF 5.268
Ning Wang,Chenyu Liu,Weihe Yao,Hengjun Zhou,Simiao Yu,Hailiang Chen,Weihong Qiao
Constructing highly efficient and multifunctional nanoparticles to overcome the multiple challenges of targeted drug delivery is a new strategy urgently needed in tumor therapy. Here, we synthesized pH-responsive prodrug ( PEG 2K -NH -N- DOX ), GSH-responsive prodrug ( PEG 2K -S-S-CPT ), folate-receptor targeting polymers ( FA-PEG 2K -L8 , FA-PEG 2K -TOS) and T1-enhanced magnetic resonance imaging contrast agents ( Gd-DTPA-N16−16) , used to encapsulate combrestatinA4 (CA4) to prepare multifunctional nanoparticles ( FTDCAG NPs). Unlike other nanoparticles, FTDCAG NPs contains three drugs with the ability to control the release in time and space, which can maximize the effectiveness of precise cancer chemotherapy. We first confirmed that specific binding between FTDCAG NPs and overexpressed folate-receptor cells by flow cytometry and confocal laser scanning microscopy. We then investigated the spatiotemporally controlled release ability of FTDCAG NPs loaded with doxorubicin (DOX), CA4 and camptothecin (CPT). Relative to pH = 7.4, the release efficiency of CA4 in the pH = 6.5 increased by 63.4 %. The first released CA4 is able to destroy the angiogenesis and help tumor cells to be exposed to the remaining FTDCG NPs. After being internalized into the tumor cells, FTDCG NPs is disassembled and the CPT and DOX were released due to the increase of intracellular GSH concentration and the decrease of pH value. Besides, the relaxation time of FTDCAG NPs is 3.86 times that of clinical Gd-DTPA, and the in vitro and vivo T1-weighted imaging is brighter, which can be used to trace the nanoparticles by MRI. Therefore, FTDCAG NPs provide an efficient strategy for the design of multifunctional drug delivery systems for enhancing antitumor efficacy.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Sustainable Chemistry & Engineering
·
2021
·
IF 8.198
Kemin Lv,Zhimeng Yu,Marcelo M. Pedroso,Bin Wu,Zhen Gao,Bingfang He,Gerhard Schenk
Establishing a suitable immobilization strategy to improve the accessibility of immobilized cellulase for insoluble cellulose and subsequently recover the enzyme from the remaining substrate is crucial to promote the industrialization of biofuels. Here, using iminodiacetic acid (IDA) and Ni2+ ions, a novel metal-chelated copolymer of methacrylic acid and methyl methacrylate was prepared for the immobilization of His-tagged processive endoglucanase EG5C-1 via affinity interaction between polyhistidine tag and Ni2+. The optimum loading capacity of the functionalized polymer (Eud-IDA-Ni2+) for EG5C-1 was about 280 mg/g, where more than 80% of the activity was recovered. Immobilized EG5C-1 exhibited improved thermal and pH stability and better reusability than the free one, and after five cycles of usage, the hydrolysis productivity remained above 70% of the initial value. The Eud-IDA-Ni2+/EG5C-1 biocomposite displayed reversibly soluble–insoluble characteristics with pH change, which was in the soluble state during the enzyme reaction process but could be recovered in an insoluble form by lowering the pH after the reaction. Thus, the yield obtained from the hydrolysis of an insoluble phosphoric acid-swollen cellulose substrate was similar for the free and immobilized form of EG5C-1. Our combined results suggested that a metal-ion-chelated, pH-responsive polymer had the potential for His-tagged cellulase immobilization to improve both the operational efficiency and economic benefit of the cellulosic biorefinery industry.
✓ 已验证
产品关联
DOI
高影响因子
FOOD HYDROCOLLOIDS
·
2021
·
IF 9.147
Yizhou Xu,Jiulin Wu,Shaoyun Wang
To overcome hydrophobicity and chemical instability of resveratrol (Rev), modified whey protein isolate (WPI) and gelatin (Gel) were used to load Rev. Three treatments including pH-shifting at pH 12 (S), pH-shifting at pH 12 combined with ultrasonication at pH 7 (SU7), and pH-shifting at pH 12 combined with ultrasonication at pH 12 (SU12) were conducted to obtain a series of modified proteins (WPI-S, WPI-SU7, WPI-SU12, Gel-S, Gel-SU7, Gel-SU12). Among them, WPI-SU12 and Gel-SU12 had the highest encapsulation efficiency (EE) and loading capacity (LC) for Rev. The EE and LC were 92.69 ± 0.25% and 17.37 ± 0.067 g/100 g protein in WPI-SU12-Rev nanocomposite , respectively, and 83.85 ± 0.43% and 15.68 ± 0.070 g/100 g protein in Gel-SU12-Rev nanocomposite, respectively. This might be related to the highest surface hydrophobicity of modified proteins in SU12 groups. The particle sizes of all nanocomposites were below 200 nm, while the higher ζ-potential absolute value of WPI-SU12-Rev nanocomposite than that of Gel-SU12-Rev nanocomposite indicated higher stability. Molecular interaction and secondary structure analysis verified that the proteins and Rev bound to each other. Moreover, protein nanocomposites could greatly improve the water solubility and antioxidant capacity of Rev. In summary, the WPI modified by ultrasonication at pH 12 showed the best loading with Rev.
✓ 已验证
产品关联
DOI
高影响因子
CEMENT AND CONCRETE RESEARCH
·
2020
·
IF 8.328
Xin Liu,Pan Feng,Wei Li,Guoqing Geng,Jiale Huang,Yun Gao,Song Mu,Jinxiang Hong
Calcium silicate hydrate (C-S-H), the most important Portland cement hydration product , determines the mechanical properties and durability of cementitious materials . In marine environment, C-S-H often suffers from sulfate attack – one of the most common and severe degradations for concrete. pH is considered as a critical factor in determining the deterioration behavior of C-S-H during sulfate attack, of which the significance may be overlooked. This study focused on the role of pH on the deterioration of C-S-H in terms of the composition and nano/micro structure under sulfate attack. The results show that lowering pH aggravates the decalcification of C-S-H, whereas a strong alkaline condition is beneficial to increase the resistance to deterioration. An increase in the mean chain length together with the proportion of large pores (>10 nm) is observed when C-S-H is subjected to low-pH sulfate attack (pH = 10–12), resulting in a relatively loose structure. The deep analysis on defective tobermorite model reveals that calcium at the interlayer of C-S-H nanostructure is readily removed under sulfate attack, thereby improving the potential of Si-O-Si groups formation and increases the mean chain length of C-S-H.
✓ 已验证
产品关联
DOI
高影响因子
NANOTECHNOLOGY
·
2021
·Vol. 32
·期 17
·175604
·
IF 3.874
Fan Liu,Yuan Jiang,HaiBao Shao,Chunlei Wang,Shuhong Xu,Rong Zhang
Precise control of the structure and bonds of doped carbon dots (CDs) is important, so that their fluorescence can be tuned as desired. Up until now, there has been a lack of effective ways to control the bonds of doped CDs. In this article, we show that the fluorescence of B/N-doped carbon dots (B/N-CDs) can be precisely tuned just by controlling their precursors' pH values. The prepared B/N-CDs exhibit two emission bands, including one emission peak at around 450 nm due to the defect state caused by low sp2 hybridization of carbon atoms, as well as another emission peak at around 360 nm caused by the B-N bond. The results for the ratio of the maximum intensity of the two emission peaks above show a linear relationship. Meanwhile, the role of the pH value of the precursors on the luminescence of B/N-CDs is deeply studied. On the one hand, the pH value affects the bonding process of CDs. N-H bonds tend to form at a low pH value, while more competitive B-N bonds exist at much higher pH value, leading to the pH-dependent intensity of the 360 nm emission band. On the other hand, a high pH value causes higher crystallinity, thus suppressing defect-state fluorescence at 450 nm. The dual effects of pH lead to precisely controlled dual-emission intensities as well as ratiometric fluorescence.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
TALANTA
·
2020
·
IF 5.339
Muhammad Mujahid Ali,Dilshad Hussain,Yan Tang,Xuechun Sun,Zhengchao Shen,Fengxia Zhang,Zhenxia Du
Boronic acid-based affinity materials have gained tremendous attention for the selective separation and recognition of cis-diol containing biomolecules. But often, these boronate affinity materials are stuck to some serious issues like high binding pH and weak affinity, especially in the case of glycoproteins . Here in this study, we used 5-boronoisophthlic acid as a novel affinity ligand for the selective capture and release of glycoproteins. The pKa value of 5-boronoisophthalic acid is investigated to be 7.8 which is just closed to physiological pH and is ideally suitable for the fast binding and elution kinetics of glycoproteins to avoid their degradation and deactivation. The affinity ligand is attached to the surface of polymer support using branched polyethyleneimine (PEI) which enhances the binding strength as it has multiple amine groups available for the attachment of 5-boronoisophthalic for synergistic interactions. The resulting affinity material is characterized and packed in a micropipette-tip using hydrophilic melamine foam as a frit to make the separation process smooth, simple, reliable, and robust. This boronic acid-based affinity tip exhibits binding constants for model glycoproteins in the range of 10 −6 –10 −7 M, binding capacities in the range of 0.662 μM/g, and selectivity up to 1:1000 (HRP to BSA) under optimized extraction conditions. Finally, the boronic-based affinity tip is successfully applied to selectively capture the glycoproteins from the human milk sample, especially lactoferrin which is highly important in dairy manufacture.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2021
·
IF 5.279
Shanshan Tie,Wentao Su,Xuedi Zhang,Yannan Chen,Xue Zhao,Mingqian Tan
The purpose of this study was to construct a delivery system using a microfluidic chip to protect procyanidins (PCs) and to achieve their pH-controlled release in simulated gastrointestinal fluid. The microfluidic chip was designed and fabricated to generate water-in-water-in-oil (W/W/O) templates for the preparation of sodium alginate/chitosan microparticles with a uniform size and core–shell structure, using an internal–external gelation method. Compared with free PCs, the stability of PCs embedded in microparticles was improved and a pH stimulus-responsive release of PCs from microparticles was observed under neutral pH conditions. The delivery system of microparticles was nontoxic and showed an inhibitory effect on the decrease of mitochondrial membrane potential in Caco-2 cells caused by H2O2 and acrylamide. This work provided a method for fabricating compact microfluidic chips to prepare a pH stimulus-responsive PCs delivery system with improved stability, which may have potential applications in the delivery of other nutrients.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）