Recognition of ClO－ and Cellular Imaging with Xanthene-based Fluorescent Probes北大核心CSCD

Selective recognition of hypochlorite ion（ClO－）in intracellular biological environment is important for research and application in cellular physiology and pathology. A novel fluorescent molecule, 6-bis （dimethylamino）-9-（1-（3-methyl-benzothiazole）-trimethyl）-xanthene（R-1）,is designed and synthesized with a combination of dimethylamino-substituted xanthene and benzothiazole segments through continuous carbon-carbon double bonds. In the presence of ClO－ ,the fluorescence emission of R-1 at 600 nm is significantly enhanced（the quantum yield is as high as 20. 3%）,and other reactive oxygen species do not affect the recognition of ClO－. Fluorescence imaging experiments demonstrate that probe R-1 can detect ClO－ in human lung adenocarinoma （A549）cells and emit red fluorescence,indicating the potential application of R-1 in ClO－ biological imaging. © 2022, Science Press (China). All rights reserved.     

Preparation and recognition performance of ratio-fluorescent probe based on sulfadiazine imprinted polymersEI北大核心CSCD

A novel ratio-fluorescent probe based on molecular imprinting polymer ( MIP) for the detection of sulfadiazine was prepared by using nitrogen-doped carbon quantum dots (N-CQDs) as the fluorescence response signal, silica-embedded cadmium telluride quantum dots ( CdTe QDs) as the fluorescence reference signal, sulfadiazine ( SDZ) as template molecule, acrylamide as functional monomer, N, N-methyl bisacrylamide as crosslinking agent and 2,2-Azobisisobutyronitrile as initiator. The results showed that the probe has a core-shell structure and fluorescence sensitive to SDZ, by the characterization of scanning electron microscopy, transmission electron microscopy, and fluorescence spectrophotometer. Under the wavelength of 360 nm, the ratio-fluorescent signal of probe showed a linear response with SDZ concentration in the range of 0-100 μmol / L with the detection limit of 11 nmol / L. Also, the ratio-fluorescent probe was applied to the detection of SDZ with a recovery of 92. 0%-95. 1% and relative standard deviation (RSD) of 3. 6% in real water samples. © 2022, Youke Publishing Co.,Ltd. All rights reserved.     

Synthesis of a flavonoid fluorescent probe for the detection of sulfur dioxide derivatives and cell imagingEI北大核心CSCD

A novel fluorescent probe HMQC was synthesized for HSOf detection by coupling flavonoid derivatives with 3-quinoline salt. In PBS buffer solution, the probe showed high selectivity, good sensitivity (58 nmol/L) and rapid response (150 s) for the detection of HSO3−. The possible sensing mechanism of the probe was discussed by nuclear magnetic hydrogen spectroscopy, mass spectrometry and theoretical calculation, indicating that the addition reaction between HSO3− and the C=C bond of the probe led to the fluorescence enhancement. The probe HMQC could be used for the detection of HSO3− in living cells, making it to be a promising tool for delecting HSO3−. © 2023, Youke Publishing Co.,Ltd. All rights reserved.     

Progress in Molecular Dynamics and Hansen Solubility Parameters of Low Molecular Weight Gels北大核心CSCD

Recently,the use of computational methods such as Molecular Dynamics（MD）simulations and Hansen Solubility Parameters （HSPs）to study the behavior of small molecule gelators has attracted much attention. MD simulation is a computational method based on classical mechanics and is one of the preferred techniques for understanding the process of small molecule gelators. The MD simulation can more accurately analyze the gelation trend or assembly behavior of small molecule gelators,dynamically and graphically display the self-assembly process,effectively reveal the relationship between the structure of small molecule gelators and related gelation behavior,and quantitatively analyze non-covalent bond interactions such as hydrogen bonds,π-π stacking,van der Waals interactions,ionic bonding and solvophobic interactions. By performing molecular dynamics simulations on known gelators/non-gelators,parameters related to gelation behavior in the simulated data are extracted,and the linear correlation is measured by fitting the Pearson correlation coefficient to finally predict the gelation behavior of a certain class of small molecules. On the other hand,the empirical model developed according to the HSPs is the most representative,which consists of the energy of dispersion interaction（δd）,the energy of polar interaction（δp）and H-bonding energy（δh ）between molecules. These three parts determine the coordinate point of the three-dimensional space（Hansen space）. According to the range of the point,it can be determined whether the organic small molecule can form a gel in a specific solvent. In this paper,representative works published recently in the field of organic small molecule gels by using MD simulations and empirical models are reviewed. Some comments on the assembly behavior of gelators,the regulation and prediction of non-covalent bond interactions on gelation ability are made. © 2022, Science Press (China). All rights reserved.     

Synthesis of a fluorescent probe based on naphthalimide derivative for simultaneous detecting of NO and pH in bioimagingEI北大核心CSCD

A new type of fluorescent probe Na-pHNO was synthesized for the simultaneous detection of NO and pH based on naphthalimide derivative. The probe had good fluorescence property in mixture solution of 99% phosphate buffer solution（PBS）and 1% dimethyl sulfoxide（DMSO）solution. It can produce a yellow-green emission peak at 544 nm,and the fluorescence intensity can be enhanced with the increase of NO concentration or the decrease of pH. The probe Na-pHNO displayed good selectivity,high sensitivity,and strong anti-interference towards NO,exhibiting good fluorescence reversibility at pH 5.5-8.5. The spectral studies showed that the probe Na-pHNO exhibited weak fluorescence due to a dual photoinduced electron transfer（PET）effect. After interacting with NO or pH,the dual PET inhibitory effect occurred,and the fluorescence intensity was significantly enhanced. The fluorescence imaging of probe Na-pHNO in HeLa cells showed that it could realize the visual monitoring of the changes of intracellular pH and NO concentration. The probe has been successfully applied to fluorescence imaging of Caenorhabditis elegans. © 2023, Youke Publishing Co.,Ltd. All rights reserved.     

Modification of Polylactic Acid by Reactive Blending with Functionalized Imidazolium-based Ionomers and Epoxy-containing Additives北大核心CSCD

Aiming to tackle the serious brittleness problem of polylactic acid（PLA）,PLA-based multiphase blends are prepared by melting reactive blending with hydroxyl functionalized ionomer as the toughening agent and compatibilizer containing epoxy groups. The structures and properties of the blends are characterized by scanning electron microscopy（SEM）,Fourier transform infrared spectrometer（FT-IR）,differential scanning calorimetry（DSC）and mechanical properties tests. The synergistic compatibilization and toughening effects of epoxy soybean oil （ESO）,polyethylene glycol diglycidyl ether （PEGDE）and ethylene-methyl acrylate-glycidyl methacrylate （AX8900） terpolymer are compared and analyzed. The results show that the compatibilization effect is closely related to the content and position of the epoxy group in the additives,which presenting different toughening effects. The addition of AX8900 can effectively improve the toughness of the blend system to obtain balanced mechanical properties. However,ESO tends to lead to crosslinking,which limits the toughening efficiency. PEGDE mainly shows a plasticizing effect,leading to the reduction of tensile strength. The results demonstrate modification of the PLA blends by reactive blending with different epoxy additives and hydroxy-containing polymers is an effective strategy for the development of high-performance biobased PLA materials. © 2022, Science Press (China). All rights reserved.     

Preparation and Properties of Poly（ether ether ketone）/Carbon Nanotube Modified Polypropylene Janus Composite Separator北大核心CSCD

Lithium-ion batteries （LIBs）have attracted wide attention because of their broad prospects in electric vehicles. However,the safety problems and low multiplier performance of the commercial polyolefin separator limit their further development,due to the poor dimensional thermal stability and low electrolyte absorption rate. Poly（ether ether ketone）（PEEK）and carbon nanotube（CNT）are compounded to coat on polypropylene （PP） to prepare Janus composite separator （PP@C） through the phase inversion method. PP@C composite separator does not deform at 180 ℃ for 0. 5 h（only slight deformation）,illustrating excellent thermal stability. The electrolyte absorption rate of PP@C2 is 193. 8%. The electrolyte uptake rate of the PP@C2 composite membrane was 193. 8%,which was 64. 5% higher than the PP membrane,showing a superduper electrolyte permeability. As a result,the specific discharge capacity of LIBs assembled with PP@C2 composite separator is 157. 6 mA·h/g at 0. 2 C and 129. 8 mA·h/g at 2 C,showing good rate performance with the capacity recovery rate of more than 99%. This might be attributed to the ultra-high thermal stability of PEEK,the good affinity of the electrolyte,the high conductivity of CNT,as well as the uniform dispersion of Li+ ,so that the separator can have excellent electrochemical performance while improving safety. © 2022, Science Press (China). All rights reserved.     

Untargeted screening and quantitation of drug residues in bean sprouts by ul⁃tra performance liquid chromatography-quadrupole/orbitrap high resolution mass spectrometryEI北大核心CSCD

A method for the untargeted screening and quantitative analysis of drug residues in bean sprouts by ultra performance liquid chromatography-quadrupole/ orbitrap high resolution mass spectrometry （UPLC-QOrbitrap HRMS） was developed. In the process of screening, the samples were extracted by acetonitrile and the data were gathered via the full MS-ddMS2 mode. In the absence of standards, qualitative analysis was carried out according to the exact mass number of precursor ions and secondary fragment ions information combined with the database. The optimized dispersive solid-phase extraction （d-SPE） method was used to purify the samples. 9 compounds in bean sprouts were screened and quantified on the basis of the peak areas of the precursor ions. 9 compounds showed good linear relationships （R2＞0.990） in the linear concentration ranges. The limits of detection of this method were between 2.0-5.0 μg/kg. The recoveries of 9 compounds at three spiked levels of 5, 10, 50 μg/kg ranged from 80.1% to 111.1%, and the relative standard deviations were less than 15%. © 2023, Youke Publishing Co.,Ltd. All rights reserved.     

Simultaneous determination of 73 fragrance allergens and 4 pesticides in silicone mosquito repellent products by ultrasonic solvent extraction combined with gas chromatography-tandem mass spectrometryEI北大核心CSCD

以73种致敏性芳香剂与4种农药为目标化合物,建立了硅胶驱蚊手环中致敏性芳香剂与农药同时测定的气相色谱-串联质谱(GC-MS/MS)方法。DB-17MS色谱柱分离,动态多反应监测模式(dMRM),外标法定量。采用阳性样品优化前处理条件,结果显示,以无水乙醇为提取溶剂、密闭控温超声提取可以有效提取硅胶样品中农药与致敏性芳香剂。最佳条件下,77种目标分析物在0.1~100 mg/L范围内线性良好(R^(2)>0.9920),定量限0.02~5.0 mg/kg,回收率66%~120%,相对标准偏差0.2%~9.8%。采用上述方法对14个驱蚊手环样品进行检测,共检出31种目标化合物。该方法可用于硅胶样品中致敏性芳香剂和农药高通量定向筛查。     

Simultaneous determination of eleven amphenicols and antiviral drugs in aquatic products by ultra-high performance liquid chromatography-tandem mass spectrometry coupled with PRIME HLB solid phase extractionEI北大核心CSCD

An efficient ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was established for the simultaneous determination of 11 amphenicols and antiviral drugs in aquatic products including fish, shrimp, soft-shell turtle and shellfish samples. Each sample was dispersed with 4%(w/w)sodium chloride solution, and extracted with 2%(V/V) ammonia-ethyl acetate solution. After the concentration of the extract, the residue was redissolved in 0.2%(V/V) aqueous solution of formic acid-acetonitrile (20∶80, V∶V), purified with Oasis PRIME HLB cartridge, and detected by UPLC-MS/MS. The samples were analyzed directly on the ZORBAX RRHD Eclipse Plus C18 column using 5 mmol/L ammonium formate and acetonitrile as mobile phase. The quantitative determination of the analytes was carried out under the multiple reaction monitoring mode with positive and negative electrospray ionization using internal standard method. Results showed that there were good linear relationships for all analytes in the corresponding concentration ranges, with the correlation coefficients not less than 0.996. The limits of quantification ranged from 0.2 to 2.0 µg/kg. The average spiked recoveries were between 84.6% and 110% with the relative standard deviations of 1.0% to 14%. The method, which has been used in risk monitoring, is suitable for rapid determination of amphenicols and antiviral drugs in aquatic products. © 2023, Youke Publishing Co.,Ltd. All rights reserved.     

环糊精超分子组装体与核酸的相互作用

环糊精是一类由6～8个D-型葡萄糖连接而成的环聚多糖分子,目前已广泛应用于化学和生物学的许多领域.综述了一些生物活性的环糊精超分子组装体,如环糊精假聚轮烷、环糊精/金纳米粒子组装体、环糊精/富勒烯组装体、环糊精/碳纳米管组装体等的构筑及其与核酸的相互作用,如对核酸的切割、凝聚、传递作用和对核酸酶的抑制作用等方面的研究进展.     

Framework Nucleic Acids for Cell Imaging and Therapy

Over the past decade,structural DNA nanotechnology has been well developed to be a promising and powerful technique to generate various nanostructures with programmability,spatial organization and biocompatibi-lity.With the advent of computer-aided tools,framework nucleic acids have been employed in a series of biomedical applications,ranging from biosensing,bioimaging,diagnosis,to therapeutics.In this review,we summarized recent advances in the construction of precisely assembled DNA nanostructures,and DNA-engineered biomimetics.We also outlined the challenges and opportunities for the translational applications of framework nucleic acids.     

耐尔蓝硫酸盐在核酸分子表面的长距组装及核酸的三波长共振光散射测定

在pH7.20～7.60及离子强度低于0.012的介质中,耐尔蓝硫酸盐(NBS)在核酸分子表面进行长距组装后,产生293.4nm、349.4nm和560.4nm的共振光散射(RLS)增强峰.根据RLS增强的Scatchard数据分析表明,NBS在小牛胸腺DNA、鱼精DNA和酵母RNA上的组装数分别是6.4、6.6和3.9,组装常数分别为7.1×10~6mol/L、4.6×10~6mol/L和1.7×10~6mol/L.应用三个波长处的RLS增强之和可以测定0～0.8mg/L的小牛胸腺DNA、鱼精DNA和0.20～0.60mg/L的酵母RNA,检测限分别是0.4、1.2和10.5μg/L.方法已成功的应用于合成样测定.     

核酸光化学生物学

光敏感基团作为光化学开关被广泛应用于各种生物过程的光调控中。特别是过去十几年内,核苷酸、寡聚核苷酸和DNA/RNA的光敏修饰策略得到了长足的发展,并在细胞信号传导和靶基因的功能调控等诸多生物学研究中发挥重要的作用。本文主要针对常用的光敏感基团、光敏感核酸及其化学生物学研究进展进行简要综述,并对未来核酸光化学生物学的研究进行了展望。     

Caprin-1 Promotes Cellular Uptake of Nucleic Acids with Backbone and Sequence Discrimination

The cellular delivery of oligonucleotides has been a major obstacle in the development of therapeutic antisense agents. PNAs (Peptide Nucleic Acid) are unique in providing a modular peptidic backbone that is amenable to structural and charge modulation. While cationic PNAs have been shown to be taken up by cells more efficiently than neutral PNAs, the generality of uptake across different nucleobase sequences has never been tested. Herein, we quantified the relative uptake of PNAs across a library of 10 000 sequences for two different PNA backbones (cationic and neutral) and identified sequences with high uptake and low uptake. We used the high uptake sequence as a bait for target identification, leading to the discovery that a protein, caprin-1, binds to PNA with backbone and sequence discrimination. We further showed that purified caprin-1 added to cell cultures enhanced the cellular uptake of PNA as well as DNA and RNA.     

功能性硫化镉纳米荧光探针荧光猝灭法测定核酸

报道了无机纳米溶胶CdS的合成，并对其进行了功能化修饰。研究了功能性CdS纳米溶胶的荧光性质。对小牛胸腺DNA进行了定量测定，考察了各种影响因素，在最佳实验条件下，该方法的线性区间0.1-1.5mg/L，检测限为0.018mg/L。与传统的有机染料相比，该方法简单、快速、灵敏度高。     

Modification of Nucleic Acids by Azobenzene Derivatives and Their Applications in Biotechnology and Nanotechnology

Azobenzene has been widely used as a photoregulator due to its reversible photoisomerization, large structural change between E and Z isomers, high photoisomerization yield, and high chemical stability. On the other hand, some azobenzene derivatives can be used as universal quenchers for many fluorophores. Nucleic acid is a good candidate to be modified because it is not only the template of gene expression but also widely used for building well‐organized nanostructures and nanodevices. Because the size and polarity distribution of the azobenzene molecule is similar to a nucleobase pair, the introduction of azobenzene into nucleic acids has been shown to be an ingenious molecular design for constructing light‐switching biosystems or light‐driven nanomachines. Here we review recent advances in azobenzene‐modified nucleic acids and their applications for artificial regulation of gene expression and enzymatic reactions, construction of photoresponsive nanostructures and nanodevices, molecular beacons, as well as obtaining structural information using the introduced azobenzene as an internal probe. In particular, nucleic acids bearing multiple azobenzenes can be used as a novel artificial nanomaterial with merits of high sequence specificity, regular duplex structure, and high photoregulation efficiency. The combination of functional groups with biomolecules may further advance the development of chemical biotechnology and biomolecular engineering.     

稀土氨基酸配合物与核酸的相互作用*

很多抗癌金属药物是以核酸为靶标。阐明小分子与核酸之间的相互作用对筛选具有高效选择性和低毒副作用的抗癌药物有重要意义。近年来,开发新型的具有对核酸序列特异性识别能力的抗癌药物己成为本领域的研究热点。稀土离子具有良好的磁学、光学、电学特性和配位能力,使稀土配合物成为新型药物试剂。然而,稀土离子在中性条件下易水解的特性极大地阻碍了稀土配合物对核酸分子识别的研究。近年来在近生理条件下合成的一系列镧系氨基酸配合物具有结构稳定、溶解性好等优点,解决了镧系离子易水解的问题。本文总结了目前关于镧系氨基酸配合物与核酸的相互作用及其序列选择性等方面的研究进展。     

基于催化发卡自组装和 Ru(NH3)63+ 的核酸光电化学灵敏分析

基于催化发卡自组装反应（CHA）和电活性材料[Ru(NH₃)₆]Cl₃,发展了一种“信号增强”型光电化学生物传感器,实现了核酸的灵敏检测. 首先,采用逐层离子吸附法（SILAR）将CdS 固定于TiO₂/ITO 电极表面. 光电材料CdS 不仅能够将TiO₂ 的吸收范围从紫外光区拓展到可见光区,而且还能提高光电转换效率. 之后,通过Cd-S 键将捕获DNA（C-DNA）固定于CdS/ TiO₂/ITO 电极表面. 与此同时,将Au 结合的发卡DNA 探针1（Au-HP1）,发卡DNA 探针2（HP2）和目标DNA（T-DNA）混合物于溶液中进行CHA 反应,得到大量的Au-HP1:HP2 复合物. 再通过Au-HP1:HP2 复合物与C-DNA 的杂交反应将大量的双链DNA 引入到电极表面. 最后,将电活性物质Ru(NH₃)₆³⁺嵌入DNA 的磷酸骨架中,从而使得光电流大幅度的增强. 该光电生物传感器检测核酸的线性范围为10 fmol·L^-1 到 1500 fmol·L^-1,检测线为6.19 fmol·L^-1,在生物分析、新药筛选以及疾病的早期诊断等方面具有潜在的应用前景.     

PNA: Synthetic Polyamide Nucleic Acids with Unusual Binding Properties

The astonishing discovery that peptide nucleic acids (PNAs, B=nucleobase), in spite of their drastic structural difference to natural DNA, are better nucleic acid mimetics than many other oligonucleotides has resulted in an explosion of research into this class of compounds. The synthesis, physical properties, and biological interactions of PNAs as well as their chimeras with DNA and RNA are summarized here.