查找使用阿拉丁产品的科研文献

Tuning monomer spatial configuration for high-performance polyesteramide loose nanofiltration membranes toward antibiotic separation

Zhixiao Liu,Yuhang Zhao,Mingli Yin,Jiaxu Wan,Yangyang Huang,Guangqiu Lei,Kangfei Wang,Tianliang Zhu,Zhengyu Qiu,Xiaoran Zhang,Zhiming Mi

Polyesteramide (PEA) thin-film composite (TFC) membranes have emerged as promising candidates for antibiotic separation from water, yet rational monomer design to overcome the permeability-selectivity trade-off remains challenging. Herein, three tetrafunctional phenol-amine monomers with distinct spatial configurations—rigid twisted 2,2-bis(3-amino-4-hydroxyphenyl)propane (BAP), rigid rotatable 3,3-dihydroxybenzidine (HAB), and bulky side-group-containing 9,9-bis(3-amino-4-hydroxyphenyl)fluorene (BAF)—were respectively reacted with trimesoyl chloride via interfacial polymerization to fabricate novel PEA loose nanofiltration (LNF) membranes. Monomer configuration governed membrane morphology, extent of crosslinking reaction, pore architecture, and surface properties. DFT calculations and UV-Vis diffusion kinetics elucidated monomer reactivity and diffusion behavior. Among the three membranes, NF-HAB, derived from HAB, demonstrated the optimal overall performance. It achieved a high water permeance of 50.5 L m −2  h −1 ·bar −1 while maintaining excellent rejection rates of both weakly negative antibiotics (e.g., 92.0% for cefoperazone) and their negatively charged sodium salts (e.g., >96% for ceftriaxone sodium and cefoperazone sodium). Furthermore, all PEA membranes exhibited superior chlorine resistance and antifouling performance. This work establishes a structure-property-mechanism relationship, demonstrating that tuning monomer spatial configuration enables synergistic optimization of permeance and selectivity for high-performance PEA LNF membranes in antibiotic separation.

A highly sensitive electrochemical sensor derived from peptide amphiphilic inspired self-assembled, ordered gold nanoparticles for determination of 22 β-lactams

Yexuan Mao,Yichao Fan,Ran Yang,Youyi Wang,Qingyue Li,Meng Dang,Xianqing Huang,Lianjun Song,Pingan Zhang,Miao Song,Liang Liu,Linli Wang,Shun Yu,Qiuyan Zhao,Xiya Zhang

Achieving ordered arrangement of gold nanoparticles (AuNPs) on an electrode can further improve the signal intensity of an electrochemical immunosensor. This ordered AuNPs self-assembly can be inspired by peptide amphiphile (PA). The rational design of hydrophobic chains in PA is a crucial step when the range of hydrophobic alkane chain from 14 to 18 carbons. As arginine (R) can combine specifically with Au surface plane (111), four PAs, i.e., C 15 H 23 CO-RR (C16R2), C 15 H 23 CO-RRR (C16R3), C 15 H 23 CO-RRRR (C16R4), and C 15 H 23 CO-RRRRR (C16R5), in this work are designed to investigate the extent of ordered AuNPs self-assembly. The results indicate that C16R4 presented a dominant electron donating ability and can inspire the self-assembly of AuNPs to form a mono-dispersed raspberry-like structure (C16R4-AuNPs) to obtain the largest ΔI (15.4 μA). In the detection system, C16R4-AuNPs firstly capture and immobilize anti-β-lactam receptor monoclonal antibodies (mAb) by electrostatic adsorption, and the anti-β-lactam receptor mAb possess antigen-antibody binding sites away from the active site of the receptors. Then, they capture β-lactam receptors through an antigen-antibody reaction to form a ternary complex (C16R4-AuNPs-mAb-β-lactam receptors). Based on this indirect-labeling process, the receptor active sites have been exposed completely, facilitating ligand recognition, which greatly further improves the sensitivity of the present method. Finally, a highly sensitive electrochemical immunosensor based on the ternary complex is developed to achieve the determination of 22 β-lactam antibiotics, which is more sensitive and applicable than other reported electrochemical sensors.

Dual-responsive ratiometric fluorescent sensor for tetracyclines detection based on europium-decorated copper nanoclusters

Mi Yuan,Mingxuan Li,Pengchen Su,Long Yu,Yunfei Lu,Mingtai Sun,Chao Yuan,Mingshun Li,Suhua Wang

Development of accurate and efficient TCs residue analysis methods is of great significance for the protection of environment, food safety and public health. Herein, a dual-responsive ratiometric fluorescence sensor being capable of simple and sensitive detection of tetracycline (TC) was presented, which was constructed by immobilizing europium ions (Eu 3+ ) onto the mercaptopropionic acid stabilized copper nanoclusters (MPA-Cu NCs). In the presence of TC, the red fluorescence of Eu 3+ was enhanced through antenna effect (AE), while the green fluorescence of MPA-Cu NCs was quenched through internal filter effect (IFE), leading to an obvious fluorescence color evolution from green to red for the probe solution. In addition to successful design of a smartphone-assisted colorimetric analysis platform for portable detection, a logic gate device capable of intelligently monitoring TC concentration is also designed.

Rapid Determination of Cephalexin in Animal-Derived Food by an Indirect Competitive Enzyme-Linked Immunosorbent Assay

Shuangmin Wu,Wei Shen,Yushuang Chen,Yongli Zhu,Ren Hou,Menghong Dai,Dapeng Peng

Synergistic D-Amino Acids Based Antimicrobial Cocktails Formulated via High-Throughput Screening and Machine Learning

Jingzhi Yang,Yami Ran,Shaopeng Liu,Chenhao Ren,Yuntian Lou,Pengfei Ju,Guoliang Li,Xiaogang Li,Dawei Zhang

Antimicrobial resistance (AMR) from pathogenic bacterial biofilms has become a global health issue while developing novel antimicrobials is inefficient and costly. Combining existing multiple drugs with enhanced efficacy and/or reduced toxicity may be a promising approach to treat AMR. D-amino acids mixtures coupled with antibiotics can provide new therapies for drug-resistance infection with reduced toxicity by lower drug dosage requirements. However, iterative trial-and-error experiments are not tenable to prioritize credible drug formulations, owing to the extremely large number of possible combinations. Herein, a new avenue is provide to accelerate the exploration of desirable antimicrobial formulations via high-throughput screening and machine learning optimization. Such an intelligent method can navigate the large search space and rapidly identify the D-amino acid mixtures with the highest anti-biofilm efficiency and also the synergisms between D-amino acid mixtures and antibiotics. The optimized drug cocktails exhibit high antimicrobial efficacy while remaining non-toxic, which is demonstrated not only from in vitro assessments but also the first in vivo study using a lung infection mouse model.

Enhanced photodegradation of ceftazidime by BiOBr(110)/BiOCl(110) composite: Its synthesis, mechanism, and degradation pathways

Yanli Sun,Xueliang Wang,Hooi Ling Lee

A simple and economical precipitation process was used to in situ synthesize a heterojunction of BiOBr(110)/BiOCl(110). Numerous techniques, such as SEM, XRD , HRTEM , BET, FTIR, and XPS , verified the successful creation of the heterostructure. In particular, the heterostructures exhibited significantly enhanced photocatalytic degradation efficiency towards ceftazidime (CFZ). The degradation kinetic constant of CFZ by BiOBr(110)/BiOCl(110) (5:5) was three times higher than those of BiOBr and BiOCl. Additionally, a type I heterojunction was reasonably suggested following UV–vis DRS and VB-XPS investigations. DFT calculations indicated that an internal electric field (IEF) was created when electrons (e - ) on the BiOBr surface were transferred to BiOCl in the dark. Upon visible light illuminated, photoinduced-e - was transferred from the conduction band (CB) of BiOCl to that of BiOBr under the action of IEF. In contrast, holes (h + ) moved in the opposite direction, realizing the separation of e - /h + pairs. Three degradation pathways were deduced based on intermediate products (IPs) detection by HPLC-MS. Importantly, the heterojunction catalyst exhibited efficient catalytic performance across solutions with different pH and maintained great reusability during four cycles of photodegradation . Overall, the work revealed distinctive insights concerning the mechanism of antibiotic degradation with BiOBr(110)/BiOCl(110) heterojunction structures .

Chelidonic acid-regulated synthesis of asymmetric polyamide nanofiltration membrane: Mechanisms and separation performance

Zhiming Mi,Lintao Liao,Lingjun Meng,Yuhang Zhao,Mingli Yin,Guangqiu Lei,Haoye Xiong,Gao Hu,Qianqian Xu,Zhixiao Liu

pH-regulated nanofiltration (NF) membranes have been used in many scenarios, but it is difficult to mitigate the inherent “permeability-selectivity” trade-off effect without the elaborate selection of acidic additives. In this study, a unique pyrone dicarboxylic acid, chelidonic acid (CHA), is selected as an additive to regulate the synthesis of asymmetric polyamide NF membrane. The asymmetric structure is confirmed by experimental characterization and theoretical simulation, further, its formation mechanism is elucidated from both thermodynamic reactivity and kinetic diffusion coefficient. Compared with the control NF membrane (Con-11.0), the thinner polyamide (PA) layer thickness and the slightly enlarged average pore diameter significantly enhance the permeation flux of NF membranes; compared with HCl-regulated NF membranes, the asymmetric structures (relatively dense upper layer of PA) of the CHA-regulated NF membranes maintain the higher rejections of Na 2 SO 4 (97.2 %) and antibiotics (96.1 % of erythromycin, 93.6 % of ceftazidime, 90.2 % of tetracycline). This greatly alleviates the “permeability-rejection” trade-off effect of NF membranes, and can be widely used in antibiotic separation and purification, and other water treatment fields. Moreover, the comparison of three typical carboxylic acids (BA, IPA and TMA) proves the specificality of pyrone structure in regulating the asymmetric NF membranes, and the importance of the structure and true ionization of acidic molecules, and their interactions with amine monomers in the interfacial polymerization regulation. The method of CHA-regulated asymmetric PA layer tactfully provides a new way to develop NF membranes with excellent comprehensive performance.

Preliminary identification and semi-quantitative characterization of a multi-faceted high-stability alginate lyase from marine microbe Seonamhaeicola algicola with anti-biofilm effect on Pseudomonas aeruginosa

Shuaiting Yun,Jinping Huang,Mingjing Zhang,Xueting Wang,Xiaochen Wang,Yanxia Zhou

Alginate lyases with unique characteristics for degrading alginate into size-defined oligosaccharide fractions, were considered as the potential agents for disrupting Pseudomonas aeruginosa biofilms. In our study, a novel endolytic PL-7 alginate lyase, named AlyG2, was cloned and expressed through Escherichia coli . This enzyme exhibited excellent properties: it maintained more than 85% activity at low temperatures of 4 °C and high temperatures of 70 °C. After 1 h of incubation at 4 °C, it still retained over 95% activity, demonstrating the ability to withstand low temperature. The acid-base and salt tolerance properties shown it preserves more than 50% activity in the pH range of 5.0 to 11.0 and in a high salt environment at 3000 mM NacCl, indicating its high stability in several aspects. More importantly, AlyG2 in our research was revealed to be effective at removing mature biofilms and inhibiting biofilm formation produced by Pseudomonas aeruginosa , and the inhibition and disruption rates were 47.25 ± 4.52% and 26.5 ± 6.72%, respectively. Additionally, the enzyme AlyG2 promoted biofilm disruption in combination with antibiotics, particularly manifesting the synergistic effect with erythromycin (FIC=0.5). In all, these results offered that AlyG2 with unique characteristics may be an effective technique for the clearance or disruption of biofilm produced by P. aeruginosa .

Preparation of high-permeance polyester nanofiltration membranes utilizing biobased phloretin derivatives for antibiotic separation

Zhixiao Liu,Yuhang Zhao,Mingli Yi,Lintao Liao,Yangyang Huang,Guangqiu Lei,Gao Hu,Mayu Lan,Huiping Li,Zhiming Mi

Antibiotics in water bodies pose a significant threat to the health of plants, animals, and humans, thereby contributing to severe ecological crises. Polyamide nanofiltration (NF) membranes are extensively employed for the separation and purification of antibiotics but are limited by relatively low permeation fluxes. In this study, three biobased phloretin derivatives—phloretin (Pt), phlorizin (Pz), and naringenin dihydrochalcone (Ng), were selected as water-phase monomers and reacted with trimesoyl chloride to fabricate three novel polyester NF membranes. The results demonstrated that the variations in the molecular structure gradients, including twisted conformation and molecular weight, of the three derivatives significantly influenced the structure and properties of polyester NF membranes. In-depth mechanistic analysis revealed that the diffusion rates (mainly related to molecular weight) of the three derivatives into the oil-phase solution, rather than their reactivity with TMC, governed the interfacial polymerization (IP) process. Consequently, Pt-based polyester NF membranes exhibited relatively dense layers compared to Pz- and Ng-based ones, achieving rejections of 92.4 % and 85.7 % for bacitracin and erythromycin, respectively, while maintaining a permeance of 35.2 L/m 2  h bar, which was significantly higher than that of conventional polyamide NF membranes. Meanwhile, the relatively loose structure of the Pz- and Ng-based polyester NF membranes made their permeance reach as high as 65.8 L/m 2 ·h·bar and 107.2 L/m 2  h bar, respectively, while maintaining intermediate separation level for five antibiotic molecules. Furthermore, the three polyester NF membranes demonstrated excellent chlorine resistance, antifouling properties, and good environmental adaptability. The three biobased polyester NF membranes in this study offer a novel approach for the development of high-flux NF membranes for antibiotic separation and other specialized scenarios. The correlation between the molecular structure of the derivatives and the membrane separation performance further deepens the understanding of polyester-based IP theory.

Lon dysfunction-mediated collateral sensitivity drives effective antibiotic combination therapies against tigecycline-resistant pathogens

Feiyu Yu,Shuyao Zhu,Qingyang Lv,Dan Fang,Haijie Zhang,Zhiqiang Wang,Yuan Liu

Tigecycline is a last-resort antibiotic primarily used to treat severe infections caused by multidrug-resistant (MDR) bacteria. However, the emergence of constantly appearing resistance determinants has drastically compromised its clinical effectiveness. Rational antibiotic combination provides a productive approach to tackle MDR pathogens. Herein, we show that evolved tigecycline-resistant Escherichia coli and Salmonella Enteritidis exhibit collateral sensitivity to aminoglycosides and nitrofurantoin. Proton motive force alterations mediate tigecycline resistance, simultaneously enhancing bacterial susceptibility to aminoglycosides. Notably, Lon dysfunction in tigecycline-resistant strains causes overexpression of sulA , increased lipopolysaccharide biosynthesis, and disrupted membrane homeostasis, leading to bacterial death upon nitrofurantoin exposure. The combination of tigecycline and nitrofurantoin effectively eradicates both evolved tigecycline-resistant bacteria and those carrying the tet (X4) gene while also hindering the development of tigecycline resistance. Together, our study suggests that combining tigecycline with existing antibiotics, rationally designed by harnessing collateral sensitivity, represents a promising therapeutic paradigm to combat tigecycline-resistant pathogens.

Rapeseed oil residue-based fluorescent probes for bifunctional detection of Hg2+ and aureomycin hydrochloride

Jiaxuan Liu,Wensi Ma,Xinyue Huang,Lei Jiang,Lin Yuan,Xiuling Ji,Yujiao Tu

Rapeseed oil residue (ROR) is the waste product of rapeseed oil extraction, mainly including protein and lignocellulose. In this study, we utilized waste ROR as the raw material to successfully prepare blue fluorescent carbon dots (ROR-CDs) by self-propagating synthesis. It demonstrated rapid preparation (20 min) with low energy consumption (400 °C) and without complicated purification processes. We analyzed the structural and optical properties of ROR-CDs. ROR-CDs exhibited exceptional fluorescence performance and stabilized, responding specifically to divalent mercury ions (Hg 2+ ) and aureomycin hydrochloride (CTC). Thus, we developed a high-sensitivity detection technique with a detection range and limit of detection (LOD) for Hg 2+ of 0–250 μg/L and 191.69 ng/L, respectively. For CTC, the detection range and LOD were 0–50 μM and 12.7 nM (S/N = 3), respectively. It is easy to operate and low-cost, ensuring efficient assistance for testing efforts in associated domains. Additionally, ROR-CDs-based detection technique can analyze Hg 2+ and CTC in the actual samples, demonstrating significant potential for application in environmental monitoring and food safety assessment.

LysR-type transcriptional regulator CARR represses the expression of blaCAR-2 and reduces P. diazotrophicus resistance to cefalothin, cefuroxime and cefotaxime

Jiansheng Lin,Chunyan Lin,Jingyang Zheng

Background: P. diazotrophicus was isolated from a newborn with D-galactosemia complicated sepsis. A homologous blaCAR-2 gene, encoding CAR-2, a predicted member of the CAR family subclass B3 metallo-β-lactamases (MBLs), was found in the genome of this strain. This study aimed to explore the identification of a novel CAR-2 protein encoded by the chromosome of P. diazotrophicus Pd1 that exhibits the zinc-binding motifs of subclass B3 enzymes and the regulatory pattern of CARR, located directly upstream of the blaCAR-2 gene, on the blaCAR-2 gene and its impact on antibiotic resistance.Methods: Antibiotic susceptibility testing was conducted by the plate agar dilution method. Site-directed mutagenesis was conducted using Mut Express II Fast Mutagenesis Kit V2. Kinetic assays were used to determine the hydrolysis of β-Lactam. The construction of bacterial knockout strains was carried out according to the principle of homologous recombination. The detection of the mRNA expression level of the gene was performed by Real-time Quantitative PCR (qPCR).Results: The minimum inhibitory concentrations (MICs) for E.coli DH5α(pHSG398::CAR-2), which expressed blaCAR-2, increased significantly for cefalothin, cefuroxime and cefotaxime sodium by 2-, 16- and 32- fold, respectively, which showed that blaCAR-2 had resistance to these three antibiotics. This protein, which was a MBL, contains two classical zinc-binding sites characteristic of subclass B3, with the amino acid motif His136, His138, His211, Asp140, His141, and His276. Among the six residues, His136, Asp140, and His211 exhibited the highest catalytic activity. We determined that CAR-2 can effectively hydrolyze cefalothin, cefuroxime and cefotaxime. The chloramphenicol resistance of the constructed E. coli DH5α strain was significantly reduced in the presence of CARR than in the absence of CARR. Compared with those for the wild-type P. diazotrophicus, MICs of cefalothin, cefuroxime and cefotaxime for the ΔCARR strain increased by 8-, 8- and 16-fold, respectively, and the expression level of blaCAR-2 also increased by approximately 10-fold.Conclusion: Overall, CAR-2 is a novel subclass B3 MBL of the CAR family that exhibits catalytic activity against cefalothin, cefuroxime and cefotaxime. CARR represses the expression of blaCAR-2, thereby reducing the resistance of P. diazotrophicus to these antibiotics. This provided a theoretical basis for revealing new mechanisms of pathogen resistance.