Browse
Submit Data
Databases
API
Help

Dataset Information

34 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Spatial and Temporal Control of Thiol-Michael Addition via Photocaged Superbase in Photopatterning and Two-Stage Polymer Networks Formation.

ABSTRACT: Photochemical processes enable spatial and temporal control of reactions, which can be implemented as an accurate external control approach in both polymer synthesis and materials applications. "Click" reactions have also been employed as efficient tools in the same field. Herein, we combined photochemical processes and thiol-Michael "click" reactions to achieve a "photo-click" reaction that can be used in surface patterning and controlled polymer network formation, owing to the ease of spatial and temporal control through use of photolabile amines as appropriate catalysts.

SUBMITTER: Xi W

PROVIDER: S-EPMC4172303 | biostudies-literature | 2014 Sep

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Spatial and Temporal Control of Thiol-Michael Addition via Photocaged Superbase in Photopatterning and Two-Stage Polymer Networks Formation.

Xi Weixian W Peng Haiyan H Aguirre-Soto Alan A Kloxin Christopher J CJ Stansbury Jeffery W JW Bowman Christopher N CN

Macromolecules 20140908 18

Photochemical processes enable spatial and temporal control of reactions, which can be implemented as an accurate external control approach in both polymer synthesis and materials applications. "Click" reactions have also been employed as efficient tools in the same field. Herein, we combined photochemical processes and thiol-Michael "click" reactions to achieve a "photo-click" reaction that can be used in surface patterning and controlled polymer network formation, owing to the ease of spatial ...[more]

PMID: 25264379

Similar Datasets

Mechanistic Kinetic Modeling of Thiol-Michael Addition Photopolymerizations via Photocaged "Superbase" Generators: An Analytical Approach.

Project description:A kinetic mechanism and the accompanying mathematical framework are presented for base-mediated thiol-Michael photopolymerization kinetics involving a photobase generator. Here, model kinetic predictions demonstrate excellent agreement with a representative experimental system composed of 2-(2-nitrophenyl)propyloxycarbonyl-1,1,3,3-tetramethylguanidine (NPPOC-TMG) as a photobase generator that is used to initiate thiol-vinyl sulfone Michael addition reactions and polymerizations. Modeling equations derived from a basic mechanistic scheme indicate overall polymerization rates that follow a pseudo-first-order kinetic process in the base and coreactant concentrations, controlled by the ratio of the propagation to chain-transfer kinetic parameters (kp/kCT) which is dictated by the rate-limiting step and controls the time necessary to reach gelation. Gelation occurs earlier as the kp/kCT ratio reaches a critical value, wherefrom gel times become nearly independent of kp/kCT. The theoretical approach allowed determining the effect of induction time on the reaction kinetics due to initial acid-base neutralization for the photogenerated base caused by the presence of protic contaminants. Such inhibition kinetics may be challenging for reaction systems that require high curing rates but are relevant for chemical systems that need to remain kinetically dormant until activated although at the ultimate cost of lower polymerization rates. The pure step-growth character of this living polymerization and the exhibited kinetics provide unique potential for extended dark-cure reactions and uniform material properties. The general kinetic model is applicable to photobase initiators where photolysis follows a unimolecular cleavage process releasing a strong base catalyst without cogeneration of intermediate radical species.

| S-EPMC5630186 | biostudies-literature

Fabrication and characterization of thiol-triacrylate polymer via Michael addition reaction for biomedical applications.

Project description:Thiol-acrylate polymers have therapeutic potential as biocompatible scaffolds for bone tissue regeneration. Synthesis of a novel cyto-compatible and biodegradable polymer composed of trimethylolpropane ethoxylate triacrylate-trimethylolpropane tris (3-mercaptopropionate) (TMPeTA-TMPTMP) using a simple amine-catalyzed Michael addition reaction is reported in this study. This study explores the impact of molecular weight and crosslink density on the cyto-compatibility of human adipose derived mesenchymal stem cells. Eight groups were prepared with two different average molecular weights of trimethylolpropane ethoxylate triacrylate (TMPeTA 692 and 912) and four different concentrations of diethylamine (DEA) as catalyst. The materials were physically characterized by mechanical testing, wettability, mass loss, protein adsorption and surface topography. Cyto-compatibility of the polymeric substrates was evaluated by LIVE/DEAD staining® and DNA content assay of cultured human adipose derived stem cells (hASCs) on the samples over over days. Surface topography studies revealed that TMPeTA (692) samples have island pattern features whereas TMPeTA (912) polymers showed pitted surfaces. Water contact angle results showed a significant difference between TMPeTA (692) and TMPeTA (912) monomers with the same DEA concentration. Decreased protein adsorption was observed on TMPeTA (912) -16% DEA compared to other groups. Fluorescent microscopy also showed distinct hASCs attachment behavior between TMPeTA (692) and TMPeTA (912), which is due to their different surface topography, protein adsorption and wettability. Our finding suggested that this thiol-acrylate based polymer is a versatile, cyto-compatible material for tissue engineering applications with tunable cell attachment property based on surface characteristics.

| S-EPMC6314209 | biostudies-literature

A Versatile Method for Preparing Polysaccharide Conjugates via Thiol-Michael Addition.

Project description:Polysaccharide conjugates are important renewable materials. If properly designed, they may for example be able to carry drugs, be proactive (e.g., with amino acid substituents) and can carry a charge. These aspects can be particularly useful for biomedical applications. Herein, we report a simple approach to preparing polysaccharide conjugates. Thiol-Michael additions can be mild, modular, and efficient, making them useful tools for post-modification and the tailoring of polysaccharide architecture. In this study, hydroxypropyl cellulose (HPC) and dextran (Dex) were modified by methacrylation. The resulting polysaccharide, bearing α,β-unsaturated esters with tunable DS (methacrylate), was reacted with various thiols, including 2-thioethylamine, cysteine, and thiol functional quaternary ammonium salt through thiol-Michael addition, affording functionalized conjugates. This click-like synthetic approach provided several advantages including a fast reaction rate, high conversion, and the use of water as a solvent. Among these polysaccharide conjugates, the ones bearing quaternary ammonium salts exhibited competitive antimicrobial performance, as supported by a minimum inhibitory concentration (MIC) study and tracked by SEM characterization. Overall, this methodology provides a versatile route to polysaccharide conjugates with diverse functionalities, enabling applications such as antimicrobial activity, gene or drug delivery, and biomimicry.

| S-EPMC8228737 | biostudies-literature

Functionalized 3D Architected Materials via Thiol-Michael Addition and Two-Photon Lithography.

Project description:Fabrication of functionalized 3D architected materials is achieved by a facile method using functionalized acrylates synthesized via thiol-Michael addition, which are then polymerized using two-photon lithography. A wide variety of functional groups can be attached, from Boc-protected amines to fluoroalkanes. Modification of surface wetting properties and conjugation with fluorescent tags are demonstrated to highlight the potential applications of this technique.

| S-EPMC5529122 | biostudies-literature

Thiol Specific and Tracelessly Removable Bioconjugation via Michael Addition to 5-Methylene Pyrrolones.

Project description:5-Methylene pyrrolones (5MPs) are highly thiol-specific and tracelessly removable bioconjugation tools. 5MPs are readily prepared from primary amines in one step. 5MPs exhibit significantly improved stability under physiologically relevant conditions and cysteine specificity compared to commonly used analogues, maleimides. Michael addition of thiol to 5MPs occurs rapidly, cleanly, and does not generate a stereocenter. The conjugates efficiently release thiols via retro-Michael reaction in alkaline buffer (pH 9.5) or via thiol exchange at pH 7.5. This unique property makes 5MPs valuable for the controlled release of conjugated cargo and temporary thiol protection. The utilization of 5MPs for protein immobilization and pull-down of active complexes is illustrated using E. coli. acetohydroxyacid synthase isozyme I.

| S-EPMC5491101 | biostudies-literature

Design of Thiol- and Light-sensitive Degradable Hydrogels using Michael-type Addition Reactions.

Project description:Injectable depots that respond to exogenous and endogenous stimuli present an attractive strategy for tunable, patient-specific drug delivery. Here, the design of injectable and multimodal degradable hydrogels that respond to externally applied light and physiological stimuli, specifically aqueous and reducing microenvironments, is reported. Rapid hydrogel formation was achieved using a thiol-maleimide click reaction between multifunctional poly(ethylene glycol) macromers. Hydrogel degradation kinetics in response to externally applied cytocompatible light, reducing conditions, and hydrolysis were characterized, and degradation of the gel was controlled over multiple time scales from seconds to days. Further, tailored release of an encapsulated model cargo, fluorescent nanobeads, was demonstrated.

| S-EPMC4536978 | biostudies-literature

Regulating the Homogeneity of Thiol-Maleimide Michael-Type Addition-Based Hydrogels Using Amino Biomolecules.

Project description:Poly(ethylene glycol) (PEG)-based synthetic hydrogels based on Michael-type addition reaction have been widely used for cell culture and tissue engineering. However, recent studies showed that these types of hydrogels were not homogenous as expected since micro domains generated due to the fast reaction kinetics. Here, we demonstrated a new kind of method to prepare homogenous poly(ethylene glycol) hydrogels based on Michael-type addition using the side chain amine-contained short peptides. By introducing such a kind of short peptides, the homogeneity of crosslinking and mechanical property of the hydrogels has been also significantly enhanced. The compressive mechanical and recovery properties of the homogeneous hydrogels prepared in the presence of side chain amine-contained short peptides were more reliable than those of inhomogeneous hydrogels while the excellent biocompatibility remained unchanged. Furthermore, the reaction rate and gelation kinetics of maleimide- and thiol-terminated PEG were proved to be significantly slowed down in the presence of the side chain amine-contained short peptides, thus leading to the improved homogeneity of the hydrogels. We anticipate that this new method can be widely applied to hydrogel preparation and modification based on Michael-type addition gelation.

| S-EPMC8628763 | biostudies-literature

Carbanion as a Superbase for Catalyzing Thiol⁻Epoxy Photopolymerization.

Project description:Photobase generator (PBG)-mediated thiol⁻epoxy photopolymerization has received widedspread attention due to its versatility in various applications. Currently, nearly all reported PBGs release amines as active species. The formed amines induce odor, yellowing, and potential toxicity. In this study, a series of novel thioxanthone-based PBGs, which were able to generate carbanion via decarboxylation under LED light irradiation, were designed and straightforwardly prepared. The formed carbanion can be used as a superbase to catalyze thiol⁻epoxy polymerization efficiently. Investigation on ¹H NMR and FT-IR confirmed the generation of carbanion intermediates. The counteranion significantly affected the photodecarboxylation efficiency. The study of photopolymerization tests, based on real-time FT-IR and dielectric analysis measurements, indicated that the generated carbanion exhibited faster polymerization rate and higher epoxy conversion than traditional superbase 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). In differential scanning calorimeter, thermogravimetric, and nanoindentation tests, comparable thermal and mechanical properties of the photocured films catalyzed by novel PBGs were obtained. The high initiation ability combined with straightforward synthesis makes these PBGs promising candidates for commercialization.

| S-EPMC6418981 | biostudies-literature

Visible-Light-Initiated Thiol-Michael Addition Polymerizations with Coumarin-Based Photobase Generators: Another Photoclick Reaction Strategy.

Project description:An efficient visible-light-sensitive photobase generator for thiol-Michael addition reactions was synthesized and evaluated. This highly reactive catalyst was designed by protecting a strong base (tetramethyl guanidine, TMG) with a visible-light-responsive group which was a coumarin derivative. The coumarin-coupled TMG was shown to exhibit extraordinary catalytic activity toward initiation of the thiol-Michael reaction, including thiol-Michael addition-based polymerization, upon visible-light irradiation, leading to a stoichiometric reaction of both thiol and vinyl functional groups. Owing to its features, this visible-light photobase generator enables homogeneous network formation in thiol-Michael polymerizations and also has the potential to be exploited in other visible-light-induced, base-catalyzed thiol-click processes such as thiol-isocynate and thiol-epoxy network-forming reactions.

| S-EPMC5176105 | biostudies-literature

Self-Healing Injectable Polymer Hydrogel via Dynamic Thiol-Alkynone Double Addition Cross-Links.

Project description:Introduction of dynamic thiol-alkynone double addition cross-links in a polymer network enable the formation of a self-healing injectable polymer hydrogel. A four-arm polyethylene glycol (PEG) tetra-thiol star polymer is cross-linked by a small molecule alkynone via the thiol-alkynone double adduct to generate a hydrogel network under ambient aqueous conditions (buffer pH = 7.4 or 8.2, room temperature). The mechanical properties of these hydrogels can be easily tuned by varying the concentration of polymer precursors. Through the dynamic thiol-alkynone double addition cross-link, these hydrogels are self-healing and shear thinning, as demonstrated by rheological measurements, macroscopic self-healing, and injection tests. These hydrogels can be injected through a 20G syringe needle and recover after extrusion. In addition, good cytocompatibility of these hydrogels is confirmed by cytotoxicity test. This work shows the application of the thiol-alkynone double addition dynamic covalent chemistry in the straightforward preparation of self-healing injectable hydrogels, which may find future biomedical applications such as tissue engineering and drug delivery.

| S-EPMC7301763 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data