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1.
Light-triggered drug delivery system is an effective strategy for precise diagnosis and therapy in cancer treatment. However, it suffers from difficultly balancing the dosimetry of drug with light dose and a lack of in vivo models for validating their clinical benefits. Here we report an unprecedented near-infrared(NIR) light photocaged cyanine-based prodrug Cy-CPT-Biotin with dual-channel fluorescence mode, enabling NIR light to precisely regulate where, when and how the intact and active prodrugs are delivered. The synergy of photochemical reaction and modulation in π-conjugated polyene backbone of cyanine can fully perform distinct dual-channel fluorescence changes in a NIR light-mediated manner. The prodrug has striking characteristics of excellent tumor-targeting ability, real-time monitoring of the in vivo behaviors by dual-channel mode and NIR-light triggering,especially for achieving fine regulation and on-demand drug release in the precise dosimetry of drug with light dose in living animals. This optical orthogonality strategy that conjuncts with NIR light-triggered and dual-channel fluorescence in vivo imaging provides a powerful tool for in vivo real-time tracking and finely tuning the prodrug release for precise drug delivery.  相似文献   

2.
The controllable synthesis of one-dimensional(1D) structural morphology of metal-organic frameworks(MOFs) is significant for its application in catalysis,sense and gas separation.In this communication,we report a simple and moderate synthetic strategy to obtain uniform HKUST-1 nanobelts(NBs) by using copper nanowires(Cu NWs) as a metal source as well as a template.The control experiments showed that synergy between metal dissolution rate and crystal formation plays a key role in the formation of nanobelts.Our study represents an attractive synthetic strategy of 1 D MOFs-based material for applications.  相似文献   

3.
The inclusion interaction between three types of methylated-β-cyclodextrins (Me-β-CDs) and albendazole (ABZ) was studied by spectrofluorimetry. The result showed that Me-β-CDs reacted with ABZ to form an inclusion complex, 1:1 stoichiometry for Me-β-CDs-ABZ complex was established and its association constant have been determined from fluorescence data by Benesi-Hildebrand's method (double reciprocal plots). It was noted that 2,6-DM-β-CD exhibited stronger binding ability than other Me-β-CDs. Based on the significant enhancement of fluorescence intensity of inclusion complex, a simple and highly sensitive fluorimetric method is proposed for the determination of ABZ in the presence of 2,6-DM-β-CD. The proposed method was successfully applied to the determination of ABZ in tablets and human urine.  相似文献   

4.
After synthesis of an asymmetric tetradentate ONN0O0 Schiff base ligand(H2L) followed by reaction of the synthesized H2 L with an equimolar mixture of methanolic solutions of the VO(acac)2, a new oxidovanadium(IV) Schiff base complex(VOL) was synthesized. The Schiff base ligand and its complex were characterized by FT-IR and UV–vis spectra and C, H, N analysis. The crystal structure of VOL was also determined by single crystal X-ray analysis. The VOL complex crystallizes in monoclinic space group Cc. The Schiff base ligand acts as a tetradentate ligand through its two iminic nitrogens and two phenolic and acetylacetonate oxygens. Thermogravimetric analysis of the VOL showed that it decomposes in two steps and converts to mixed vanadium oxides at 477 8C. In addition, thermal decomposition of the VOL complex in air at 660 8C leads to formation of V2O5 nanoparticles with the average size estimated from XRD 49 nm. The catalytic activity of the VOL complex was investigated in the epoxidation reaction and different reaction parameters were optimized. The results showed that the cyclic alkenes were efficiently converted to the corresponding epoxides, whereas the VOL did not appreciably convert the linear alkenes.  相似文献   

5.
"Click chemistry" is, by definition, a general functionalization methodology (GFM) and its marriage with living anionic polymerization is particularly powerful in precise macromolecular synthesis. This paper reports the synthesis of a "clickable" middle-chain azide-functionalized polystyrene (mPS-N3 ) by anionic polymerization and its application in the preparation of novel shape amphiphiles based on polyhedral oligomeric silsesquioxane (POSS). The mPS-N3 was synthesized by coupling living poly(styryl)lithium chains (PSLi) with 3-chloropropylmethyldichlorosilane and subsequent nucleophilic substitution of the chloro group in the presence of sodium azide. Excess PSLi was end-capped with ethylene oxide to facilitate its removal by flash chromatography. The mPS-N3 was then derived into a giant lipid-like shape amphiphile in two steps following a sequential "click" strategy. The copper(I)-catalyzed azide-alkyne cycloaddition between mPS-N3 and alkyne-functionalized vinyl-substituted POSS derivative (VPOSS-alkyne) ensured quantitative ligation to give polystyrene with VPOSS tethered at the middle of the chain (mPS-VPOSS). The thiol-ene reaction with 1-thioglycerol transforms the vinyl groups on the POSS periphery to hydroxyls, resulting in an amphiphilic shape amphiphile, mPS-DPOSS. This synthetic approach is highly efficient and modular. It demonstrates the "click" philosophy of facile complex molecule construction from a library of simple building blocks and also suggests that mPS-N3 can be used as a versatile "clickable" motif in polymer science for the precise synthesis of complex macromolecules.  相似文献   

6.
The inclusion interaction between berberine hydrochloride(BRH) and cucurbit[7](CB[7]) has been studied by spectro-fluorimetry. The result showed that CB[7]interaction with BRH to form a stable inclusion complex with an association constant of 9.57×10~4 L/mol and the fluorescence intensity of the complex was enhanced in 17 times higher than that of the studied drug itself. Based on the significant enhancement of fluorescence intensity of B RH in inclusion complex,a spetrofluorimetric method with high sens...  相似文献   

7.
The inclusion interaction between three types of methylated-β-cyclodextrins (Me-β-CDs) and albendazole (ABZ) was studied by spectrofluorimetry. The result showed that Me-β-CDs reacted with ABZ to form an inclusion complex, 1: 1 stoichiometry for Me- β-CDs-ABZ complex was established and its association constant have been determined from fluorescence data by Benesi- Hildebrand's method (double reciprocal plots). It was noted that 2,6-DM-β-CD exhibited stronger binding ability than other Me-β- CDs. Based on the significant enhancement of fluorescence intensity of inclusion complex, a simple and highly sensitive fluorimetric method is proposed for the determination of ABZ in the presence of 2,6-DM-β-CD. The proposed method was successfully applied to the determination of ABZ in tablets and human urine.  相似文献   

8.
A novel near-infrared light photothemal-activated H2S-donating nanocomposite hydrogel was developed,through combination of a thermo-labile H2S donor and photothermal nanoparticles in agarose hydrogel.The polyethylenimine dithiocarbamate polymer,a thermo-labile compound,was synthesized as a novel H2S donor.The combination of a thermo-labile hydrogen sulfide donor and photothermal nanoparticles enabled the generation of H2S in agarose hydrogel upon irradiation with near-infrared light.The ability to modulate the photoirradiation for controlled generation and spatiotemporally release of H2S are its specific advantages.This photothermal spatiotemporally controlled H2S-releasing strategy was successfully applied to anti-inflammation treatment in a rat model,demonstrating its utility as a novel H2S-based therapeutic approach.  相似文献   

9.
Synthesis and characteristics of poly(3,4-azopyridylene) (PAP), conductivity and oxygen-binding affinity of its complex with meso-α,α,α,α-tetrakis(o-pivalamidophenyl) porphyrinatocobalt(Ⅱ) (CoP) were studied. PAP was prepared by oxidative polymerization of 3,4-diaminopyridine (DAP) in DMF solution using CuCl/pyridine as the catalyst. IR and NMR results showed that the peak of amido group in DAP was converted to the azo group in PAP and a π conjugated polymer was synthesized. The average molecular weight of PAP was determined to be 5.0 × 103. The PAP-CoP complex was prepared by complexing the pyridyl group of PAP with the fifth coordination site of CoP in DMF solution. In comparison with the CoP complex with a non-π conjugated polymer, the PAP-CoP complex shows good electroconductivity of 5.8 × 10-6 Scm-1. The PAP-CoP complex displays a reversible change in the UV-Visible absorption spectrum from the deoxy form to the oxy or oxygen-binding one with an isosbestic point, in response to the partial oxygen pressure of the atmosphere. The oxygen-response behavior was monitored at the absorbance ascribed to the oxy form at 548 nm to give the oxygen-binding affinity.The oxygen-binding equilibrium curves of PAP-CoP complex obey a Langmuir isotherm. DMF has great effects on the oxygen-binding properties of the PAP-CoP complex. The oxygen-binding affinity of PAP-CoP complex in the solid state is higher than that in DMF solution. With decreasing temperature, the oxygen-binding affinity of the PAP-CoP complex increases.  相似文献   

10.
11.
Kinetic and thermodynamic studies reveal that the property of significantly enhanced catalytic activity with colloidal stability is attributed to an efficacious means of tuning enzyme-substrate association by varying with the rate constants in the presence of functionalized gold nanoparticles.  相似文献   

12.
寡糖合成中的“预活化”策略   总被引:1,自引:0,他引:1  
耿轶群  叶新山 《化学进展》2007,19(12):1896-1902
寡糖及其缀合物因其重要的生物学功能而日益受到人们的关注,由于糖链结构的复杂性与多样性,寡糖的化学合成具有很大的挑战性。为了减少合成及分离步骤,提高寡糖合成的效率,糖基化策略十分重要。"一釜合成法"由于进行多个连续的糖基化反应但不需分离中间体而具有很大优势,但传统"一釜法"在设计单糖模块时需要进行精细复杂的保护基操作和离去基调整而影响其合成效率。"预活化"寡糖合成策略不依赖于糖基供体与糖基受体的活性差异,无需复杂的保护基操作,所有偶联反应在同一条件下一釜完成,实现了寡糖的高效、快速合成。本文在简要介绍传统"一釜合成法"的基础上,对"预活化"策略的研究进展进行综述,重点介绍"预活化"策略的基本原理,发展过程及其在生物活性寡糖合成上的应用。  相似文献   

13.
The strategy of metal ion complexation is employed to design a delivery system for an antifouling agent (AFA) in marine paints. A poly(1-vinylimidazole-co-methyl methacrylate) copolymer (PVM), together with Cu2+ or Zn2+ formed a PVM-M2+ complex. The AFA, Medetomidine, was then coordinated into the complex. The coordination strength was investigated in solution by 1H NMR and on solid surfaces by using the Quartz Crystal Microbalance with Dissipation monitoring technique (QCM-D) and Surface Plasmon Resonance (SPR). From the 1H NMR experiments strong interactions were observed between Cu2+ and the PVM-polymer and between Medetomidine and the PVM-Cu2+ complex. From the QCM-D and SPR measurements it was shown that Cu2+, compared to Zn2+, exhibited a larger affinity for the PVM-copolymer surface that resulted in higher degree of swelling of the polymer film. Large amounts of Medetomidine were adsorbed to the PVM-Cu2+ complex resulting in low desorption rates. However, the adsorbed amount of Medetomidine was lower to the Zn2+ doped polymer and a higher desorption rate was observed. These results indicate the possibility of tuning the release of Medetomidine by altering the coordinating metal ion, which may prove to be favorable in a paint formulation.  相似文献   

14.
Hetero-assembling of spherical building blocks with well-defined spatial distribution holds great significance in developing chiral nanostructures. Herein, a strategy for hetero-assembling of gold nanoparticles(Au NPs) was demonstrated using rigid bifacial DNA origami as templates. By tuning the sizes and the fixed location of Au NPs on DNA origami, right-handed and left-handed Au NPs nanostructures were respectively constructed. Gel electrophoresis indicated the formation of the DNA origami-Au NPs complex and transmission electron microscopy(TEM) visually displayed the arrangement of Au NPs in these two chiral structures. The spatial configuration and 3D geometry of Au NPs were further illustrated by the stereographic TEM with tilting angles from ?30° to 30°. This strategy provides a universal approach to construct the asymmetrical 3D geometries, which may have potential applications in biomimicking and nanophotonics.  相似文献   

15.
Site‐selective isotopic labeling of amide carbonyls offers a nonperturbative means to introduce a localized infrared probe into proteins. Although this strategy has been widely used to investigate various biological questions, the dependence of the underlying amide I vibrational frequency on electric fields (or Stark tuning rate) has not been fully determined, which prevents it from being used in a quantitative manner in certain applications. Herein, through the use of experiments and molecular dynamics simulations, the Stark tuning rate of the amide I vibration of an isotopically labeled backbone carbonyl in a transmembrane α‐helix is determined to be approximately 1.4 cm?1/(MV/cm). This result provides a quantitative basis for using this vibrational model to assess local electric fields in proteins, among other applications. For instance, by using this value, we are able to show that the backbone region of a dipeptide has a surprisingly low dielectric constant.  相似文献   

16.
When enzymes are optimized for biotechnological purposes, the goal often is to increase stability or catalytic efficiency. However, many enzymes reversibly convert their substrate and product, and if one is interested in catalysis in only one direction, it may be necessary to prevent the reverse reaction. In other cases, reversibility may be advantageous because only an enzyme that can operate in both directions can turnover at a high rate even under conditions of low thermodynamic driving force. Therefore, understanding the basic mechanisms of reversibility in complex enzymes should help the rational engineering of these proteins. Here, we focus on NiFe hydrogenase, an enzyme that catalyzes H(2) oxidation and production, and we elucidate the mechanism that governs the catalytic bias (the ratio of maximal rates in the two directions). Unexpectedly, we found that this bias is not mainly determined by redox properties of the active site, but rather by steps which occur on sites of the proteins that are remote from the active site. We evidence a novel strategy for tuning the catalytic bias of an oxidoreductase, which consists in modulating the rate of a step that is limiting only in one direction of the reaction, without modifying the properties of the active site.  相似文献   

17.
The unique electron-transport and emissive properties of tris(8-quinolinolate) aluminum(III) (Alq(3)) have resulted in extensive use of this material for small molecular organic light-emitting diode (OLED) fabrication. So far, efforts to prepare stable and easy-to-process red/green/blue (RGB)-emitting Alq(3) derivatives have met with only a limited success. In this paper, we describe how the electronic nature of various substituents, projected via an arylethynyl or aryl spacer to the position of the highest HOMO density (C5), may be used for effective emission tuning to obtain blue-, green-, and red-emitting materials. The synthetic strategy consists of four different pathways for the attachment of electron-donating and electron-withdrawing aryl or arylethynyl substituents to the 5-position of the quinolinolate ring. Successful tuning of the emission color covering the whole visible spectrum (lambda=450-800 nm) was achieved. In addition, the photophysical properties of the luminophores were found to correlate with the Hammett constant of the respective substituents, providing a powerful strategy with which to predict the optical properties of new materials. We also demonstrate that the electronic nature of the substituent affects the emission properties of the resulting complex through effective modification of the HOMO levels of the quinolinolate ligand.  相似文献   

18.
Complex solid‐solution electrocatalysts (also referred to as high‐entropy alloy) are gaining increasing interest owing to their promising properties which were only recently discovered. With the capability of forming complex single‐phase solid solutions from five or more constituents, they offer unique capabilities of fine‐tuning adsorption energies. However, the elemental complexity within the crystal structure and its effect on electrocatalytic properties is poorly understood. We discuss how addition or replacement of elements affect the adsorption energy distribution pattern and how this impacts the shape and activity of catalytic response curves. We highlight the implications of these conceptual findings on improved screening of new catalyst configurations and illustrate this strategy based on the discovery and experimental evaluation of several highly active complex solid solution nanoparticle catalysts for the oxygen reduction reaction in alkaline media.  相似文献   

19.
In this work we present an effective and flexible computational approach, which is the result of an ongoing development in our groups, allowing the complete a priori simulation of the ESR spectra of complex systems in solution. The usefulness and reliability of the method are demonstrated on the very demanding playground represented by the tuning of the equilibrium between 3(10)- and alpha-helices of polypeptides by different solvents. The starting point is the good agreement between computed and X-ray diffraction structures for the 3(10)-helix adopted by the double spin-labelled heptapeptide Fmoc-(Aib-Aib-TOAC)2-Aib-OMe. Next, density functional computations, including dispersion interactions and bulk solvent effects, suggest another energy minimum corresponding to an alpha-helix in polar solvents, which, eventually, becomes the most stable structure. Computation of magnetic and diffusion tensors provides the basic ingredients for the building of complete spectra by methods rooted in the Stochastic Liouville Equation (SLE). The remarkable agreement between computed and experimental spectra at different temperatures allowed us to identify helical structures in the various solvents. The generality of the computational strategy and its implementation in effective and user-friendly computer codes pave the route toward systematic applications in the field of biomolecules and other complex systems.  相似文献   

20.
The 1:1 benzofuran–formaldehyde complex has been chosen as model system for analyzing π→π* interactions in supramolecular organizations involving heteroaromatic rings and carbonyl groups. A joint “rotational spectroscopy–quantum chemistry” strategy unveiled the dominant role of π→π* interactions in tuning the intermolecular interactions of such adduct. The exploration of the intermolecular potential energy surface led to the identification of 14 low-energy minima, with 4 stacked isomers being more stable than those linked by hydrogen bond or lone-pair→π interactions. All energy minima are separated by loose transition states, thus suggesting an effective relaxation to the global minimum under the experimental conditions. This expectation has been confirmed by the experimental detection of only one species, which was unambiguously assigned owing to the computation of accurate spectroscopic parameters and the characterization of 11 isotopologues. The large number of isotopic species opened the way to the determination of the first semi-experimental equilibrium structure for a molecular complex of such a dimension.  相似文献   

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