32620-90-9Relevant academic research and scientific papers
A Mechanochemical Reaction Cascade for Controlling Load-Strengthening of a Mechanochromic Polymer
Boulatov, Roman,Pan, Yifei,Tian, Yancong,Wang, Chenxu,Weng, Wengui,Xiang, Shishuai,Xu, Piaoxue,Zhang, Huan
, p. 21980 - 21985 (2020)
We demonstrate an intermolecular reaction cascade to control the force which triggers crosslinking of a mechanochromic polymer of spirothiopyran (STP). Mechanochromism arises from rapid reversible force-sensitive isomerization of STP to a merocyanine, which reacts rapidly with activated C=C bonds. The concentration of such bonds, and hence the crosslinking rate, is controlled by force-dependent dissociation of a Diels–Alder adduct of anthracene and maleimide. Because the adduct requires ca. 1 nN higher force to dissociate at the same rate as that of STP isomerization, the cascade limits crosslinking to overstressed regions of the material, which are at the highest rate of material damage. Using comb polymers decreased the minimum concentration of mechanophores required to crosslinking by about 100-fold compared to previous examples of load-strengthening materials. The approach described has potential for controlling a broad range of reaction sequences triggered by mechanical load.
Maleimide-bearing nanogels as novel mucoadhesive materials for drug delivery
Tonglairoum, Prasopchai,Brannigan, Ruairí P.,Opanasopit, Praneet,Khutoryanskiy, Vitaliy V.
, p. 6581 - 6587 (2016)
Novel maleimide-functionalised nanogels have been synthesised via the polymerisation of 2,5-dimethylfuran-protected 3-maleimidoethyl butylacrylate in the presence of presynthesised poly(N-vinylpyrrolidone) (PVP) nanogel scaffolds using surfactant-free emulsion polymerisation techniques. The protected maleimide nanogels were subsequently deprotected to generate the reactive maleimide group via a retro-Diels-Alder reaction. These activated nanogels were found to exhibit excellent mucoadhesive properties on ex vivo conjunctival tissue when compared to the known mucoadhesive chitosan. In order to determine the viability of the materials as drug carriers, nanogels were loaded with a model drug compound and the in vitro release kinetics were analysed. The nanogels could sustain the release of a model drug compound over several hours owing to the swellable hydrophilic nanogel structure, exhibiting first order release kinetics. As a consequence, these findings support the potential of these maleimide-bearing nanogels as a novel platform for sustained drug delivery.
Bridging from the Sequence to Architecture: Graft Copolymers Engineering via Successive Latent Monomer and Grafting-from Strategies?
Zhang, Yajie,Cao, Xiaohuan,Gao, Yang,Xie, Yujie,Huang, Zhihao,Zhang, Zhengbiao,Zhu, Xiulin
, p. 1273 - 1280 (2021)
The on-demand building copolymer structures, from sequence to architecture, is crucial in understanding the relation between polymer structure and property, meanwhile motivating the innovation of polymer hierarchy. However, the challenge is conspicuous for complicated polymer structures from inherently intricate polymerization. In this work, copolymers with tailored grafting density and distributions were achieved using successive latent monomer and grafting-from strategies. The hydroxyl group functionalized furan/maleimide adduct (FMOH) was selected as the latent monomer for RAFT polymerization of an array of copolymers with tailored localization of hydroxyl group along the main chain. The hydroxyl group further initiated the ring opening polymerization (ROP) of L-lactide or ε-caprolactone, resulting in a library of multicomponent copolymers via grafting-from strategy. The initiating efficiency reached to ~100% with variable molecular weight (21300—58600 Da) and narrow distributions (DM 1.25), indicating that such graft copolymers possessed controlled density and distribution of side chains as its linear template. The investigation on thermal properties of the well-defined graft copolymers implied that the precise tailoring over copolymer structures at the molecule level could lead to tunable chemical/physical properties. This work bridged polymer from sequence to architecture, unveiled a new method in creating graft copolymers with programmable structures and provided the insight into the structure/property relationship.
Tuning the self-healing behavior of one-component intrinsic polymers
K?tteritzsch, Julia,Hager, Martin D.,Schubert, Ulrich S.
, p. 321 - 329 (2015)
Novel terpolymers with furan and maleimide units as functional moieties for the reversible crosslinking by the Diels-Alder (DA) reaction with different polar and nonpolar co-monomers and linkers have been prepared for potential applications as self-healing coatings. The synthesized linear one-component systems are able to crosslink via the functional units in the side chain (i.e. furan and maleimide) resulting in a highly crosslinked network. The terpolymers contain different maleimide methacrylates with three different linkers (MIMA 1, MIMA 2, MIMA 3), which vary in the length and the composition of the spacer unit as well as furfuryl methacrylate (FMA) as active units. Moreover, as polar co-monomers hydroxyethyl methacrylate (HEMA), dimethylaminoethyl methacrylate (DMAEMA) as well as 2-(hydroxyethoxy)ethyl methacrylate (DEGMA) and as nonpolar co-monomer butyl methacrylate (BMA) were used. The terpolymers were characterized using 1H NMR spectroscopy and SEC measurements; the thermal properties were studied by TGA and DSC investigations as well as the self-healing properties by real-time analyses using a microscope equipped with a camera.
Nucleus-Targeted Organoiridium–Albumin Conjugate for Photodynamic Cancer Therapy
Zhang, Pingyu,Huang, Huaiyi,Banerjee, Samya,Clarkson, Guy J.,Ge, Chen,Imberti, Cinzia,Sadler, Peter J.
, p. 2350 - 2354 (2019)
An organoiridium–albumin bioconjugate (Ir1-HSA) was synthesized by reaction of a pendant maleimide ligand with human serum albumin. The phosphorescence of Ir1-HSA was enhanced significantly compared to parent complex Ir1. The long phosphorescence lifetime and high 1O2 quantum yield of Ir1-HSA are highly favorable properties for photodynamic therapy. Ir1-HSA mainly accumulated in the nucleus of living cancer cells and showed remarkable photocytotoxicity against a range of cancer cell lines and tumor spheroids (light IC50; 0.8–5 μm, photo-cytotoxicity index PI=40–60), while remaining non-toxic to normal cells and normal cell spheroids, even after photo-irradiation. This nucleus-targeting organoiridium-albumin is a strong candidate photosensitizer for anticancer photodynamic therapy.
Reversible-Addition Fragmentation Chain Transfer Step-Growth Polymerization
Tanaka, Joji,Archer, Noel Edward,Grant, Michael Jeffery,You, Wei
supporting information, p. 15918 - 15923 (2021/10/21)
Reversible-addition fragmentation chain transfer (RAFT) polymerization has been widely explored since its discovery due to its structural precision, versatility, and efficiency. However, the lack of tunability of the polymer backbone limits some applications. Herein, we synergistically combine RAFT and step-growth polymerization mechanisms, by employing a highly selective insertion process of a single monomer with a RAFT agent, to achieve RAFT step-growth polymerization. A unique feature of the RAFT step-growth polymers is that each backbone repeat unit bears a pendant RAFT agent, which can subsequently graft side chains in a second polymerization step and afford molecular brush polymers. Enabled by cleavable backbone functionality, we demonstrate transformation of the resulting brushlike polymers into linear chains of uniform size upon a stimulus.
Glass-transition temperature governs the thermal decrosslinking behavior of Diels–Alder crosslinked polymethacrylate networks
Dobbins, Daniel J.,Scheutz, Georg M.,Sun, Hao,Crouse, Christopher A.,Sumerlin, Brent S.
, (2019/11/13)
A series of Diels–Alder (DA) crosslinked polymethacrylate networks covering a broad range of glass-transition temperatures (Tg) was prepared to establish the relationship between the Tg and the thermal decrosslinking behavior of these networks. A series of permanently crosslinked and uncrosslinked analogues were also prepared to better understand the thermoset-to-thermoplastic transition occurring in the DA networks at elevated temperatures. The network series were studied using dynamic mechanical analysis, which established an inverse relationship between Tg and decrosslinking ability. Differential scanning calorimetry confirmed the viability of the DA linkages in all formulations, and a trapping experiment with 9-anthracenemethanol demonstrated that even the least responsive network was capable of undergoing decrosslinking given appropriate thermal treatment. While polymer chain mobility has long been understood to be a critical factor in healable materials, this work verifies the importance of this parameter in the decrosslinking of DA networks.
Stereochemical effects on the mechanochemical scission of furan-maleimide Diels-Alder adducts
Wang, Zi,Craig, Stephen L.
supporting information, p. 12263 - 12266 (2019/10/22)
Clarifying the correlation between the chemical structure of mechanophores and their mechanical reactivity informs the design of mechanochemical systems. One specific correlation that has received much recent attention is that between stereoisomerism and mechanical reactivity. Here, we report previously unobserved differences in the mechanical reactivity of furan-maleimide Diels-Alder (DA) stereoisomers. We evaluated the internal competition between the mechanically triggered retro-DA reaction and the mechanochemical ring opening of gem-dichlorocyclopropane mechanophores in the pulsed sonication of polymer solutions. The relative extent of the two sonomechanochemical reactions in the same polymer shows that the endo DA isomer exhibits greater mechanical lability than its exo isomer. This result contrasts with recent measurements of the relative rates of scission in a similar system and points to potential enhanced sensitivity obtained through the use of internal competition as opposed to absolute rates in assessing mechanical reactivity in sonication studies.
A strategy combining quantitative reactions and reversible-covalent chemistry for sequential synthesis of sequence-controlled polymers with different sequences
Xu, Chao-Ran,Zhang, Ze,Pan, Cai-Yuan,Hong, Chun-Yan
, p. 294 - 304 (2019/04/25)
A new strategy combing quantitative reactions and reversible-covalent chemistry is proposed for sequential synthesis of a series of sequence-controlled polymers with different sequences. Using a Michael addition reaction between acrylate and thiol, an aminolysis reaction of five-membered cyclic dithiocarbonate and a thiol substitution reaction of bromomaleimide and thiol, AB-, AB'C- and AB'CD-sequenced molecules are synthesized via AB, AB'C and AB'CD sequential monomer additions, respectively. These three molecules all have furan-protected maleimido group at one end, and the other end of AB-, AB'C- and AB'CD-sequenced molecules is amine, thiol and anthracene groups, respectively. Due to the fact that the furan-protected maleimido group can be efficiently transformed to maleimide group at high temperature via retro Diels-Alder reaction, AB-, AB'C- and AB'CD-sequenced molecules polymerize into sequence-controlled polymers with corresponding sequences at 120 °C. Through this strategy, the synthesis of molecular modules does not require separation and purification, and sequence-controlled polymers with specific sequence can be synthesized in a one-pot process via adding different monomers and adjusting reaction condition.
Aromatic Nitrogen Mustard-Based Autofluorescent Amphiphilic Brush Copolymer as pH-Responsive Drug Delivery Vehicle
Saha, Biswajit,Choudhury, Neha,Seal, Soma,Ruidas, Bhuban,De, Priyadarsi
, p. 546 - 557 (2019/01/08)
Delivery of clinically approved nonfluorescent drugs is facing challenges because it is difficult to monitor the intracellular drug delivery without incorporating any integrated fluorescence moiety into the drug carrier. The present investigation reports the synthesis of a pH-responsive autofluorescent polymeric nanoscaffold for the administration of nonfluorescent aromatic nitrogen mustard chlorambucil (CBL) drug into the cancer cells. Copolymerization of poly(ethylene glycol) (PEG) appended styrene and CBL conjugated N-substituted maleimide monomers enables the formation of well-defined luminescent alternating copolymer. These amphiphilic brush copolymers self-organized in aqueous medium into 25-68 nm nanoparticles, where the CBL drug is enclosed into the core of the self-assembled nanoparticles. In vitro studies revealed ～70% drug was retained under physiological conditions at pH 7.4 and 37 °C. At endolysosomal pH 5.0, 90% of the CBL was released by the pH-induced cleavage of the aliphatic ester linkages connecting CBL to the maleimide unit. Although the nascent nanoparticle (without drug conjugation) is nontoxic, the drug conjugated nanoparticle showed higher toxicity and superior cell killing capability in cervical cancer (HeLa) cells rather than in normal cells. Interestingly, the copolymer without any conventional chromophore exhibited photoluminescence under UV light irradiation due to the presence of "through-space" π- π interaction between the C=O group of maleimide unit and the adjacent benzene ring of the styrenic monomer. This property helped us intracellular tracking of CBL conjugated autofluorescent nanocarriers through fluorescence microscope imaging. Finally, the 4-(4-nitrobenzyl)pyridine (NBP) colorimetric assay was executed to examine the ability of CBL-based polymeric nanomaterials toward alkylation of DNA.
