- 标题
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Polysiloxane-based Hyperbranched Fluorescent Materials Prepared by Thiol-ene “Click” Chemistry as Potential Cellular Imaging Polymers
摘要： Hyperbranched polymers have attracted increasing interest due to their unique properties which possess excellent RI and thermal stability, and have been widely used in fields of drug delivery, catalysts, liquid crystal and so on. Herein, polysiloxane-based hyperbranched fluorescent materials (P1 and P2) were synthesized by thiol-ene “click” chemistry. Then, novel polysiloxane-based hyperbranched fluorescent materials (P1-Ln3+) has been prepared by rare earth ions coordination. In view of the splendid fluorescence characteristics and favorable stability of P1-Ln3+, it has been applied in biological imaging. P1-Ln3+ has gained commendable applications in bioimaging.
关键词： Fluorescence materials,Living cells imaging,Hyperbranched polymers,Thiol-ene "click" chemistry,Coordination,Rare earth ions
更新于2025-09-23 15:23:52
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Photodynamic Antimicrobial Cellulosic Material Through Covalent Linkage of Protoporphyrin IX onto Lyocell Fibers
摘要： Here, we report the preparation of porphyrin-functionalized Lyocell fibers according to an azide-alkyne click concept. First, azido-modified Lyocell fibers and alkynylated protoporphyrin building blocks were prepared through alkoxysilane chemistry and Steglich esterification, respectively. Lyocell fibers were pre-activated by swelling in organic solvents in order to increase the accessibility of hydroxyl groups in the subsequent silanization process. The azide-equipped cellulosic matrix reacted with the propargyl groups of the protoporphyrin IX derivative in a copper-catalyzed azide-alkyne cycloaddition reaction (CuAAC), by which protoporphyrin IX was introduced onto the surface of the Lyocell fibers. The modified building blocks and the final functionalized cellulosic materials were comprehensively characterized by FTIR, NMR, UV/Vis spectroscopy and elemental analysis. Photo-bactericidal activity of modified fibers against 2 gram-positive bacteria strains, including Staphylococcus aureus and Bacillus subtilis, were investigated and compared to those of unmodified and azido-modified Lyocell fibers. The results confirmed the photo-antibacterial activity of the synthesized fibers against both bacteria strains.
关键词： photoactivity,protoporphyrin IX,cellulose fibers,click chemistry,Alkoxysilane
更新于2025-09-23 15:23:52
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The role of dipole structure and their interaction on the electromechanical and actuation performance of homogeneous silicone dielectric elastomers
摘要： Grafting polar groups onto elastomer chains has proven to be an effective method to achieve high performance homogenous dielectric elastomers (DE). Up to now, there still lacks an in-depth understanding of the effect of structure and content of these grafted dipoles on the electromechanical properties of the modified DE. In this study, three kinds of polar groups including carboxyl (COOH), hydroxyl (OH), and ester (COOCH3) are grafted onto Polymethylvinylsiloxane (PMVS) by using a photochemical thiol-ene reaction to prepare PMVS-COOH, PMVS-OH and PMVS-COOCH3 DE. Three grafting degrees (15%, 50% and 95%) were prepared for each kind of modified PMVS. Interestingly, although the dipolar moment of COOH is higher than that of OH and COOCH3, at the same grafting degree, the dielectric constant of PMVS-OH is much higher than that of PMVS-COOCH3 and PMVS-COOH. At high grafting degree (50% and 95%), the actuated strain at a specific electric field of PMVS-OH is significantly higher than that of PMVS-COOH and PMVS-COOCH3. The actuated train at a 15 kV/mm sharply increases from 0.2% for PMVS to 9.1% for PMVS-OH with the grafting degree of 95%, higher than that of the commercial silicone DE and the new structured silicone DE reported previously. These dielectric, mechanical and actuated properties are affected by the combined effects of moment, mobility and interactions of these dipoles, which have been deeply discussed. The present study provides guidance for the preparation of high-performance homogeneous DE by rational designing the dipolar structure and content.
关键词： Polymethylvinylsiloxane,dipoles,electromechanical properties,thiol-ene click chemistry,dielectric elastomers,actuated strain
更新于2025-09-23 15:23:52
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Stable Molecular Surface Modification of Nanostructured, Mesoporous Metal Oxide Photoanodes by Silane and Click Chemistry
摘要： Binding functional molecules to nanostructured mesoporous metal oxide surfaces provides a way to derivatize metal oxide semiconductors for applications in dye-sensitized photoelectrosynthesis cells (DSPECs). The commonly used anchoring groups, phosphonates and carboxylates, are unstable as surface links to oxide surfaces at neutral and high pH, leading to rapid desorption of appended molecules. A synthetically versatile molecular attachment strategy based on initial surface-modification with a silyl azide followed by click chemistry is described here. It has been used for the stable installation of surface-bound metal complexes. The resulting surfaces are highly stabilized toward complex loss with excellent thermal, photochemical, and electrochemical stabilities. The procedure involves binding 3-azidopropyltrimethoxysilane (APTMS) to nanostructured mesoporous TiO2 or tin-doped indium oxide (ITO) electrodes by silane attachment followed by azide-terminated, Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reactions with an alkyne-derivatized ruthenium(II) polypyridyl complex. The chromophore-modified electrodes display enhanced photochemical and electrochemical stabilities compared to phosphonate surface binding with extended photoelectrochemical oxidation of hydroquinone for more than ~6 h with no significant decay.
关键词： DSPECs,photostability,stability,silane chemistry,electrostability,Ru(II) polypyridyl complexes,click chemistry,Dye-sensitized,photoanode
更新于2025-09-23 15:22:29
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Enzyme immobilization in completely packaged freestanding SU-8 microfluidic channel by electro click chemistry for compact thermal biosensor
摘要： Enzyme immobilization method in packaged freestanding microfluidic channel is developed for biomolecule assembly of biosensor in this research. A new micro fluidic fabrication method is proposed to fabricate freestanding fluidic structure by MEMS technology. The SU-8 polymer channel is treated by plasma treatment to change hydrophobic surface to hydrophilic property which can automatically drive the liquid into the channel by capillary force. The electro click chemistry method is carried out in hydrophilic SU-8 micro channel by capillary effect. The results show that enzyme immobilization can be immobilized by electro click chemistry in completely packaged freestanding channel. The proposed enzyme immobilization method in micro channel is capable of minimizing biosensor device for healthcare application.
关键词： Capillary effect,SU-8 polymer,Electro click chemistry,Enzyme immobilization,Microfluidic
更新于2025-09-23 15:22:29
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An Enzyme-Free MicroRNA Assay Based-on Fluorescence Counting of Click Chemical Ligation-Illuminated Magnetic Nanoparticles with Total Internal Reflection Fluorescence Microscopy
摘要： MicroRNAs (miRNAs) have been considered as promising cancer biomarkers. However, the simple but sensitive detection of low levels of miRNAs in biological samples still remains challenging. Herein, we wish to report an entirely enzyme-free, simple and highly sensitive miRNA assay based on the counting of cycling click chemical ligation (3CL)-illuminated fluorescent magnetic nanoparticles (MNPs) with a total internal reflection fluorescence microscopy (TIRFM). In this strategy, each miRNA molecule can trigger many cycles of click chemical ligation reactions to produce plentiful ligated oligonucleotides (ODNs) with both 5’-biotin and 3’-fluorophore, resulting in efficient signal amplification. It is worth noting that only the ligated ODNs can bring fluorophores onto streptavidin-functionalized MNPs (STV-MNPs). Notably, merely 10 fluorescent molecules on each 50 nm MNP can make it bright enough to be clearly visualized by the TIRFM, which can significantly improve the detection sensitivity for miRNA. Through fluorescence counting of individual MNPs and integrating their fluorescence intensities, the amount of target miRNA can be quantitatively determined. This miRNA assay can be accomplished in a mix-and-read manner just by simply mixing the enzyme-free 3CL reaction system with the MNPs before TIRFM imaging, which avoids tedious immobilization, washing and purification steps. Despite the extremely simple operation, this strategy exhibits high sensitivity with a quite low detection limit of 50 fM target miRNA as well as high specificity to well discriminate miRNA sequences with a single-base variation. Furthermore, the applicability of this method in real biological samples is also verified through the accurate detection of miRNA target in cancer cells.
关键词： click chemistry,microRNA,TIRFM,magnetic nanoparticle,fluorescence counting
更新于2025-09-23 15:21:21
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Triple Orthogonal Labeling of Glycans Applying Photoclick Chemistry
摘要： Bioorthogonal labeling of multiple biomolecules is of current interest in chemical biology. For the visualization of carbohydrates, metabolic glycoengineering (MGE) has been shown to be an appropriate approach. Here, we report that the nitrile imine–alkene cycloaddition (photoclick reaction) is a suitable ligation reaction in MGE. Using a mannosamine derivative with an acrylamide reporter group, that is efficiently metabolized by cells and that quickly reacts in the photoclick reaction, we achieved the labeling of sialic acids on the surface of living cells. Screening of several alkenes unraveled that a previously reported carbamate-linked methylcyclopropene reporter, that is well suited for the inverse-electron-demand Diels-Alder (DAinv) reaction, has a surprisingly low reactivity in the photoclick reaction. This enabled us to achieve for the first time a triple labeling of glycans by the combination of DAinv, photoclick, and copper-free click chemistry.
关键词： carbohydrates,tetrazines,bioorthogonal reactions,click chemistry,metabolic engineering
更新于2025-09-23 15:21:21
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Controlled Covalent Functionalization of 2H-MoS2 with Molecular or Polymeric Adlayers.
摘要： Most air-stable 2D materials are relatively inert, which makes their chemical modification difficult. In particular, in the case of MoS2, the semiconducting 2H-MoS2 is much less reactive than its metallic counterpart, 1T-MoS2. As a consequence, there are hardly any reliable methods for the covalent modification of 2H-MoS2. An ideal method for the chemical functionalization of such materials should be both mild, not requiring the introduction of a large number of defects, and versatile, allowing for the decoration with as many different functional groups as possible. Herein, a comprehensive study on the covalent functionalization of 2H-MoS2 with maleimides is presented. The use of a base (Et3N) leads to the in situ formation of a succinimide polymer layer, covalently connected to MoS2. In contrast, in the absence of base, functionalization stops at the molecular level. Moreover, the functionalization protocol is mild (occurs at room temperature), fast (nearly complete in 1h), and very flexible (11 different solvents and 10 different maleimides tested). In practical terms, the procedures described here allow for the chemist to manipulate 2H-MoS2 in a very flexible way, decorating it with polymers or molecules, and with a wide range of functional groups for subsequent modification. Conceptually, the spurious formation of an organic polymer might be general to other methods of functionalization of 2D materials, where a large excess of molecular reagents is typically used.
关键词： click chemistry,MoS2,maleimide,2D materials,covalent functionalization
更新于2025-09-23 15:21:01
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Alkyne Functionalization of a Photoactivated Ruthenium Polypyridyl Complex for Click-Enabled Serum Albumin Interaction Studies
摘要： Studying metal-protein interactions is key for understanding the fate of metallodrugs in biological systems. When a metal complex is not emissive and too weakly bound for mass spectrometry analysis, however, it may become challenging to study such interactions. In this work a synthetic procedure was developed for the alkyne functionalization of a photolabile ruthenium polypyridyl complex, [Ru(tpy)(bpy)(Hmte)](PF6)2, where tpy = 2,2′:6′,2′′-terpyridine, bpy = 2,2′-bipyridine, and Hmte = 2-(methylthio)ethanol. In the functionalized complex [Ru(HCC-tpy)(bpy)(Hmte)](PF6)2, where HCC-tpy = 4′-ethynyl-2,2′:6′,2′′-terpyridine, the alkyne group can be used for bioorthogonal ligation to an azide-labeled fluorophore using copper-catalyzed “click” chemistry. We developed a gel-based click chemistry method to study the interaction between this ruthenium complex and bovine serum albumin (BSA). Our results demonstrate that visualization of the interaction between the metal complex and the protein is possible, even when this interaction is too weak to be studied by conventional means such as UV?vis spectroscopy or ESI mass spectrometry. In addition, the weak metal complex-protein interaction is controlled by visible light irradiation, i.e., the complex and the protein do not interact in the dark, but they do interact via weak van der Waals interactions after light activation of the complex, which triggers photosubstitution of the Hmte ligand.
关键词： ruthenium polypyridyl complex,click chemistry,bovine serum albumin,photoactivation,alkyne functionalization,metal-protein interactions
更新于2025-09-23 15:21:01
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Visible-Light-Activated High-Density Materials for Controlled in Vivo Insulin Release
摘要： In this work, we describe the synthesis, characterization, and ultimate in vivo assessment of second-generation insulin photoactivated depot (PAD) materials. These are the first to use visible light to stimulate insulin release and have an in vivo performance that is 28-fold improved relative to first-generation materials. This improvement is due to two major factors linked to the utilized chemistry: (1) we have incorporated the coumarin photo-cleavable group, which increases the photorelease wavelength into the visible range, enhancing tissue penetration of the light; (2) photo-toggling of insulin solubility is produced by linking three insulin molecules to a central bridge via light cleaved groups, and not by bonding to a large polymer. The resulting trimer is, therefore, highly dense (87% insulin dry w/w) but retains the insolubility required of the approach. Only after irradiation with visible light is native, soluble insulin released from the dermal depot. This high density increases the amount and ease of insulin release, as the density of photolytic groups is 10?20-fold higher than in polymer-based first-generation materials. We have synthesized new azide-terminated coumarin linkers that we react with the amine groups of insulin. Using mass spectrometry methods, we identify the sites of reaction and purify individual isomers, which we demonstrate have in vitro photolysis rates that are within a factor of 2 of each other. We then reacted these terminal azide groups with a tridentate strained alkyne linker. We show that the resulting insulin trimer is highly insoluble, but can be milled into injectable particles that release insulin only in response to light from a 406 nm light source. Finally, we demonstrate that these materials have a significantly improved in vivo performance, releasing 28-fold more insulin on a per energy basis than first-generation materials.
关键词： photolysis,protein chemistry,insulin,coumarin,click chemistry
更新于2025-09-23 15:19:57