Search Results (14)

Cellulose tosylate (MCC-Tos) is a key derivative for surface modification and a crucial precursor for cellulose compatibilization in click reactions, enabling its functionalization for advanced applications. Replacing tosyl groups with alkyne groups broadens cellulose’s potential in biocompatible reactions, such as thiol-yne click chemistry and protein/enzyme immobilization. To achieve this, we optimized the heterogeneous synthesis of MCC-Tos using a Doehlert matrix statistical design, evaluating the influence and interaction of the reaction conditions. The optimized conditions—144 h reaction time, 10:1 molar ratio, and 30 °C—yielded a degree of substitution for tosyl groups (DS_tos) of 1.80, determined via elemental analysis and FTIR-ATR spectroscopy. The reaction kinetics followed a first-order model. A subsequent reaction with propargylamine produced aminopropargyl cellulose (MCC-P_NH), reducing DS_tos by 65%, which was confirmed via FTIR, and improving thermal stability by a margin of 30 °C (TGA/DTG). ¹³C CP/MAS NMR confirmed the alkyne group attachment, further validated via coupling an azide-functionalized coumarin through copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC). Fluorescence microscopy and UV spectroscopy were used to estimate a substitution degree of 0.21. This study establishes a feasible route for synthesizing alkyne-functionalized cellulose, paving the way for eco-friendly materials, including protein/enzyme bioconjugates, composites, and advanced materials via thiol-yne and CuAAC reactions. Full article

Graft copolymers have gained significant importance in various fields due to their tunable functionality and well-defined architecture. However, there are still limitations due to the compatibility of monomers and functional groups depending on the polymerization mode. Click chemistry has solved this problem through its ability to easily and quantitatively link a wide range of polymers and functional groups. The combination of click chemistry, including copper-catalyzed azide-alkyne cycloaddition (CuAAC), thiol-ene, and thiol-yne reactions, with various polymerization techniques offers a promising solution for the robust and efficient preparation of graft copolymers with the desired architecture and functionality. In this review, we present successful applications of click chemistry in the production of well-defined graft copolymers with diverse functionalities such as for electronics, energy devices, biomedical applications, and nanotechnology. Full article

The study delves into the use of the thiol-yne click reaction to enhance (bio)conjugation methodologies, particularly focusing on immobilizing biomolecules onto PLLA surfaces. The thiol-yne click reaction, known for its efficiency, selectivity, and versatility in forming carbon-sulfur bonds under mild conditions without transition metal catalysts, is explored for conjugating the fluorophore dansyl onto PLLA surfaces. This approach aims to broaden bioconjugation strategies beyond traditional methods like the Michael-type reaction, expanding their applicability to diverse biomolecules. Utilizing a photoinitiator and specific light for photo-immobilization, the thiol-yne click reaction offers spatial and temporal control, with the absence of transition metal catalysts mitigating concerns of cytotoxicity and metal contamination, rendering it suitable for biomedical applications. The objectives of this research encompass demonstrating the feasibility of the thiol-yne click reaction for surface functionalization and enriching bioconjugation strategies for tailoring PLLA surfaces, ultimately advancing biomedical technologies through precise control over surface properties and functionality. For this purpose, PLLA surfaces were activated through hydrolysis and amidation to introduce the activated alkyne moiety (PLLA-Alkyne), followed by photo-induced dansyl immobilization (PLLA-Dns) with Irgacure 651. Various surface characterization techniques, including SEM, WCA, XPS, ATR-FTIR, and fluorescence microscopy and spectroscopy, validated the successful conjugation. This metal-free method preserves the material’s bulk properties while enabling thiol-containing molecule immobilization. Full article

Nanomaterials have been extensively used in several applications in the past few decades related to biomedicine and healthcare. Among them, nanogels (NGs) have emerged as an important nanoplatform with the properties of both hydrogels and nanoparticles for the controlled/sustained delivery of chemo drugs, nucleic acids, or other bioactive molecules for therapeutic or diagnostic purposes. In the recent past, significant research efforts have been invested in synthesizing NGs through various synthetic methodologies such as free radical polymerization, reversible addition-fragmentation chain-transfer method (RAFT) and atom transfer radical polymerization (ATRP), as well as emulsion techniques. With further polymeric functionalizations using activated esters, thiol–ene/yne processes, imines/oximes formation, cycloadditions, nucleophilic addition reactions of isocyanates, ring-opening, and multicomponent reactions were used to obtain functionalized NGs for targeted delivery of drug and other compounds. NGs are particularly intriguing for use in the areas of diagnosis, analytics, and biomedicine due to their nanodimensionality, material characteristics, physiological stability, tunable multi-functionality, and biocompatibility. Numerous NGs with a wide range of functionalities and various external/internal stimuli-responsive modalities have been possible with novel synthetic reliable methodologies. Such continuous development of innovative, intelligent materials with novel characteristics is crucial for nanomedicine for next-generation biomedical applications. This paper reviews the synthesis and various functionalization strategies of NGs with a focus on the recent advances in different biomedical applications of these surface modified/functionalized single-/dual-/multi-responsive NGs, with various active targeting moieties, in the fields of cancer theranostics, immunotherapy, antimicrobial/antiviral, antigen presentation for the vaccine, sensing, wound healing, thrombolysis, tissue engineering, and regenerative medicine. Full article

Every year millions of people worldwide undergo surgical interventions, with the occurrence of mild or severe post-treatment consequences meaning that rehabilitation plays a key role in modern medicine. Considering the cases of burns and plastic surgery, the pressing need for new materials that can be used for wound patches or body fillers and are able to sustain tissue regeneration and promote cell adhesion and proliferation is clear. The challenges facing next-generation implant materials also include the need for improved structural properties for cellular organization and morphogenic guidance together with optimal mechanical, rheological, and topographical behavior. Herein, we propose for the first time a sodium alginate hydrogel obtained by a thiol–yne reaction, easily synthesized using carbodiimide chemistry in a two-step reaction. The hydrogels were formed in all cases within a few minutes of light irradiation, showing good self-standing properties under solicitation. The mechanical, rheological, topographical, and swelling properties of the gels were also tested and reported. Lastly, no cytotoxicity was detected among the hydrogels. Soluble extracts in culture media allowed cell proliferation, and no differences between samples were detected in terms of metabolic activity and DNA content. These results suggest the potential use of these cytocompatible hydrogels in tissue engineering and regenerative medicine. Full article

Visible-light photoredox catalysis has been established as a popular and powerful tool for organic transformations owing to its inherent characterization of environmental friendliness and sustainability in the past decades. The thiol-ene/yne reactions, the direct hydrothiolation of alkenes/alkynes with thiols, represents one of the most efficient and atom-economic approaches for the carbon-sulfur bonds construction. In traditional methodologies, harsh conditions such as stoichiometric reagents or a specialized UV photo-apparatus were necessary suffering from various disadvantages. In particular, visible-light photoredox catalysis has also been demonstrated to be a greener and milder protocol for the thiol-ene/yne reactions in recent years. Additionally, unprecedented advancements have been achieved in this area during the past decade. In this review, we will summarize the recent advances in visible-light photoredox catalyzed thiol-ene/yne reactions from 2015 to 2021. Synthetic strategies, substrate scope, and proposed reaction pathways are mainly discussed. Full article

Traditional antibacterial hydrogels have a broad-spectrum bactericidal effect and are widely used as wound dressings. However, the biological toxicity and drug resistance of these antibacterial hydrogels cannot meet the requirements of long-term clinical application. Imidazolium poly(ionic liquids) (PILs) are polymeric antibacterial agents exhibiting strong antibacterial properties, as they contain a strong positive charge. In this study, two imidazolium PILs, namely poly(N-butylimidazolium propiolic acid sodium) (PBP) and poly(N-(3,6-dioxaoctane) imidazolium propiolic acid sodium) (PDP), as high efficiency antibacterial agents, were synthesized by polycondensation reaction. Then, the PILs were compounded with polyethylene glycol (PEG) by a thiol-yne click reaction to prepare injectable antibacterial hydrogels. An in vitro assay showed that the injectable antibacterial hydrogels could not only quickly kill Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), but also had low toxicity for human skin fibroblasts cells (HSFs) and human umbilical vein endothelial cells (HUVECs), respectively. Additionally, the lipopolysaccharide (LPS) inflammation model revealed that the injectable antibacterial hydrogels also had anti-inflammatory effects, which would be advantageous to accelerate wound healing. Full article

Petroleum contains a large number of heteroatomic compounds, but today, most of them are not efficiently utilized. The constant development of the sustainability concept recalls for rethinking the usage of fossil resources with improved chemical utility. In order to initiate research aimed at involving active petroleum compounds in chemical transformations, a new analytical method for product detection is needed. Here, we study the click reaction of thiols with alkynes, leading to the formation of α-vinyl sulfides directly in the petroleum environment. The reaction was carried out using an (IMes)Pd(acac)Cl catalyst, which demonstrated tolerance to petroleum components. In this study, the concentration of thiols ranged from 1 M to 0.01 M (from 8% to 0.1%). To detect products at low concentrations, a special alkyne labeled with an imidazole moiety was used. This approach made it possible to observe the formation of vinyl sulfides by electrospray ionization mass spectrometry (ESI-MS), which provides an opportunity for further optimization of the reaction conditions and future developments for the direct involvement of oil components in chemical reactions. Full article

This paper is review with 119 references. Approaches to supplant currently used plastics with materials made from more sustainably-sourced monomers is one of the great contemporary challenges in sustainable chemistry. Fatty acids are attractive candidates as polymer precursors because they can be affordably produced on all inhabited continents, and they are also abundant as underutilized by-products of other industries. In surveying the array of synthetic approaches to convert fatty acids into polymers, those routes that produce organosulfur polymers stand out as being especially attractive from a sustainability standpoint. The first well-explored synthetic approach to fatty acid-derived organosulfur polymers employs the thiol-ene click reaction or the closely-related thiol-yne variation. This approach is high-yielding under mild conditions with up to 100% atom economy and high functional group tolerance. More recently, inverse vulcanization has been employed to access high sulfur-content polymers by the reaction of fatty acid-derived olefins with elemental sulfur. This approach is attractive not only because it is theoretically 100% atom economical but also because elemental sulfur is itself an underutilized by-product of fossil fuel refining. The thiol-ene, inverse vulcanization, and mechanistically-related thiol-yne and classic vulcanization are therefore discussed as promising routes to access polymers and composites from fatty acid-derived precursors. Full article

Click chemistry has emerged as an effective polymerization method to obtain thermosets with enhanced properties for advanced applications. In this article, commonly used click reactions have been reviewed, highlighting their advantages in obtaining homogeneous polymer networks. The basic concepts necessary to understand network formation via click reactions, together with their main characteristics, are explained comprehensively. Some of the advanced applications of thermosets obtained by this methodology are also reviewed. Full article

In this contribution, we propose a novel functional surface-enhanced Raman spectroscopy (SERS) platform for the detection of one of the most hazardous heavy metal ions, Hg²⁺. The design of the proposed sensor is based on the combination of surface plasmon-polariton (SPP) supporting gold grating with the high homogeneity of the response and enhancement and mercaptosuccinic acid (MSA) based specific recognition layer. For the first time, diazonium grafted 4-ethynylphenyl groups have undergone the sunlight-induced thiol–yne reaction with MSA in the presence of Eosine Y. The developed SERS platform provides an extremely sensitive, selective, and convenient analytical procedure to detect mercury ions with limit of detection (LOD) as low as 10⁻¹⁰ M (0.027 µg/L) with excellent selectivity over other metals. The developed SERS sensor is compatible with a portable SERS spectrophotometer and does not require the expensive equipment for statistical methods of analysis. Full article

The core-shell structure molecularly imprinted magnetic nanospheres towards hypericin (Fe₃O₄@MIPs) were prepared by mercapto-alkyne click polymerization. The shape and size of nanospheres were characterized by dynamic light scattering (DLS) and transmission electron microscope (TEM). The nanospheres were analyzed by FTIR spectroscopy to verify the thiol-yne click reaction in the presence or absence of hypericin. The Brunauer–Emmet–Teller (BET) method was used for measuring the average pore size, pore volume and surface area. The Fe₃O₄@MIPs synthesized displayed a good adsorption capacity (Q = 6.80 µmol·g⁻¹). In addition, so-prepared Fe₃O₄@MIPs showed fast mass transfer rates and good reusability. The method established for fabrication of Fe₃O₄@MIPs showed excellent reproducibility and has broad potential for the fabrication of other core-shell molecularly imprinted polymers (MIPs). Full article

To fabricate molecularly imprinted polymer nanospheres via click reaction, five different clickable compounds were synthesized and two types of click reactions (azide-alkyne and thiol-yne) were explored. It was found that molecularly imprinted polymer nanospheres could be successfully synthesized via thiol-yne click reaction using 3,5-diethynyl-pyridine (1) as the monomer, tris(3-mercaptopropionate) (tri-thiol, 5) as the crosslinker, and hypericin as the template (MIP–NSHs). The click polymerization completed in merely 4 h to produce the desired MIP–NSHs, which were characterized by FTIR, SEM, DLS, and BET, respectively. The reaction conditions for adsorption capacity and selectivity towards hypericin were optimized, and the MIP–NSHs synthesized under the optimized conditions showed a high adsorption capacity (Q = 6.03 μmol•g−1) towards hypericin. The imprinting factors of MIP–NSHs towards hypericin, protohypericin, and emodin were 2.44, 2.88, and 2.10, respectively. Full article

Most classical dendrimers are frequently built-up from identical repeating units of low valency (usually AB2 monomers). This strategy necessitates several generations to achieve a large number of surface functionalities. In addition, these typical monomers are achiral. We propose herein the use of sugar derivatives consisting of several and varied functionalities with their own individual intrinsic chirality as both scaffolds/core as well as repeating units. This approach allows the construction of chiral, dense dendrimers with a large number of surface groups at low dendrimer generations. Perpropargylated β-D-glucopyranoside, serving as an A5 core, together with various derivatives, such as 2-azidoethyl tetra-O-allyl-β-D-glucopyranoside, serving as an AB4 repeating moiety, were utilized to construct chiral dendrimers using “click chemistry” (CuAAC reaction). These were further modified by thiol-ene and thiol-yne click reactions with alcohols to provide dendritic polyols. Molecular dynamic simulation supported the assumption that the resulting polyols have a dense structure. Full article