STAR Protocols
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2024
·
IF 1.3
Qina Lin,Jie Chen,Yichuan Zhang,Quan Gao,Liwei Zhu,Qi Xing,Jin Geng
Summary Due to the higher and more rapid consumption of carbohydrates by cancer cells compared to normal cells, carbohydrates can be effectively employed as a targeted therapeutic strategy for tumor treatment. Here, we present a protocol for synthesizing sequence-controlled glycooligomers using both solution-phase and solid-phase systems. We outline detailed procedures for evaluating the safety and tumor-targeting properties of the sequence-controlled glycooligomers in vivo . For complete details on the use and execution of this protocol, please refer to Chen et al. 1
研究领域:
生物化学
·
药物开发
·
肿瘤学
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产品关联
DOI
PubMed
高影响因子
Polymer Chemistry
·
2019
·Vol. 11
·期 6
·1211-1219
·
IF 4.76
Fu-Rong Zeng,Jing Xu,Lin-Hao Sun,Jimei Ma,Hong Jiang,Zi-Long Li
Poly(ester amide)s (PEAs) attract considerable attention owing to their intriguing properties. However, the establishment of precise structure–property relationship for PEAs is hindered by the ambiguous primary structures of these biologically important polymers. Herein, we propose polyesterification as an efficient strategy for the synthesis of copolymers of ε-caprolactone (CLo) and ε-caprolactam (CLa). Two sorts of AB-type monomers bearing halogen and carboxylic acid terminal groups, namely 6-bromohexanoic acid (1) and 6-(6-bromohexanamido)hexanoic acid (2), underwent nucleophilic substitution in a step-growth manner to furnish P(CLo) (P0) and P(CLo-alt-CLa) (P5), respectively. Moreover, random copolymers P1–P4 were also synthesized by copolymerization of 1 and 2 in predetermined feed ratios. Thermal properties, crystal structure, surface wettability, thermal responsiveness and degradation profiles of P0–P5 along with P(CLa) (P6) were investigated. The melting ranges of polymers P0–P6 become narrowed if the structural regularity is pronounced, and the melting temperatures (Tms) are fundamentally determined by chemical composition and sequence distribution. The crystal structures and morphologies of P0–P6 are influenced by their chemical compositions, and the unit cell changes from orthorhombic to α-monoclinic while increasing the molar fraction of the CLa unit. Moreover, alternating copolymer P5 shows upper critical solution temperature (UCST) behavior in dimethyl sulfoxide (DMSO).
研究领域:
高分子化学
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材料科学
·
生物医学工程
✓ 已验证
DOI
高影响因子
Polymer Chemistry
·
2017
·Vol. 9
·期 1
·108-120
·
IF 5.375
Lincan Yang,Hongwei Ma,Li Han,Xinyu Hao,Pibo Liu,Heyu Shen,Yang Li
The alkynyl-functionalized 1,1-diphenylethylene (DPE) derivative DPE-yne was incorporated into a polymer chain through living anionic polymerization (LAP). An unanticipated coupling reaction occurred and could be restrained by extra feeding of DPE derivatives. Investigating the mechanism of the side coupling indicated that excess P-SLi coupled with the DPE-yne units in the chain when the feed of DPE-yne was insufficient. Although the use of excess DPE-yne can effectively restrain the side coupling during the copolymerization, these conditions afford only an alternating polymer sequence. For the diversity of sequence structure and multi-functionalization, another DPE derivative, DPE-NMe2, was introduced into the polymerization, and the use of an appropriate amount of DPE-NMe2 effectively inhibited the side coupling. Additionally, two functional groups (alkynes and amines) can be incorporated into polymer chains, and their sequence distribution was investigated. The in situ1H NMR method was applied to monitor the chain propagation during the terpolymerization in real time. The in situ1H NMR results showed that the entire sequence is a gradient structure with compositional drift from a predominant St-(DPE-yne) fraction initially to a St-(DPE-NMe2) fraction finally, and the sequence between them is a gradual transition fraction. Consistent with the special sequence distribution in the polymer chain, the terpolymerization kinetic was investigated, and the apparent kinetic constants for each monomer were obtained. The corresponding reactivity ratios (rSt) were also calculated. The rSt-Dyne and rSt-Dnme were simulated as 0.08 and 5.8 during the terpolymerization, respectively. The terpolymerization investigated here not only inhibited the side coupling reaction but also allowed the introduction of a third functional monomer; moreover, its sequence structure shows potentially novel and intriguing properties that could further the applications of functionalized polymers.
研究领域:
高分子化学
·
材料科学
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产品关联
DOI
高影响因子
ACS Applied Polymer Materials
·
2023
·
IF 5
Yanan Li,Wenfang Zheng,Shengjie Yin,Renming Pan,Wenxi Li,Xiangyang Lin
In the field of energetic materials (EMs), soft chains are copolymerized with energetic polymers to improve flexibility. However, this often makes it difficult to achieve simultaneous optimization of the energy level and flexibility due to the random sequence. In this study, a simple approach is presented to develop energetic sequence-controlled polymers (ESCPs), alternate copolymers poly(3,3-bis(azidomethyl)oxetane-glycol) (P(BAMO-alt-EG)) and poly(3,3-bis(azidomethyl)oxetane-tetrahydrofuran) (P(BAMO-alt-THF)), through click reactions. This approach provides the potential to design and control mechanical and thermal properties in propellant binders by introducing various segments and regulating the sequence structure. These polymers display excellent thermal stability and demonstrate that regulated shorter segmental length promoted better flexibility and less residual carbon content without compromising the energy level of the propellant. The obtained kinetic parameters prove that P(BAMO-alt-EG) released higher heat and accelerated the thermolysis process compared to P(BAMO-alt-THF). These results demonstrate the potential of highly alternating ESCPs as a potential energetic propellant binder.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
MACROMOLECULES
·
2015
·
IF 5.8
Ze Zhang,Ye-Zi You,De-Cheng Wu,Chun-Yan Hong
Multicomponent reactions have recently attracted a great deal of attention as they are considered as a powerful tool for constructing sequence-controlled polymers. Although new examples are constantly flourishing in the literature, the process that allows two or more consecutive multicomponent-reactions to react in a single operation for the syntheses of sequence-controlled polymers has not been developed until now. Here, we propose a new strategy combining multicomponent reaction of amine, thiol, and alkene conjugating and multicomponent polymerization of diyne, azide, and diamine coupling in one-pot for the synthesis of sequence-controlled polymer.
研究领域:
高分子化学
·
有机合成
✓ 已验证
DOI
高影响因子
EUROPEAN POLYMER JOURNAL
·
2018
·
IF 3.741
Lei Yu,Ze Zhang,Ye-Zi You,Chun-Yan Hong
Sequence-controlled polymers are prepared by the combination of thiol-ene click reaction and amino-yne click reaction. Due to the high selectivity of the amine unit and thiol unit toward thiolactone, methacrylate, propiolate, etc., the sequence of the resulting polymers can be easily controlled by monomer-addition sequence. Moreover, thiol-ene click reaction and amino-yne click reaction can be carried out under mild conditions without need of any catalyst. Different kinds of sequence-controlled copolymers have been prepared by the combination of thiol-ene click reaction and amino-yne click reaction in one pot. NMR spectra and GPC traces confirmed the formation of polymers with high molecular weight and controlled sequence structure. Therefore, we provide a new method for the preparation of functional polymers with well-controlled sequences.
研究领域:
高分子化学
·
材料科学
✓ 已验证
DOI
高影响因子
EUROPEAN POLYMER JOURNAL
·
2019
·
IF 3.621
Shixue Wang,Hao Zhang,Wenjing He,Hua Zhou,Youhua Tao
The synthesis of sequence-controlled polymers is an important emerging trend in recent polymer science. However, the relationship between the sequence structure and performance of the polymer was rarely studied. Here, we synthesized a series of sequence-controlled proline-based multi-block copolymers via one-pot iterative RAFT polymerization , it achieved high monomer conversions (>98%), precise control of molecular weight, and low polydispersity. The relationship studied between the sequence structure of multi-block copolymers and thermoresponsive performance revealed that the LCSTs of these copolymers are sequence dependent, and it can be altered by variation the sequence structure. In addition, temperature-variable 1 H NMR analysis and dissipative particle dynamics (DPD) simulation technique were chosen to further study on the nature of phase transition and the relationship between sequence structure and thermoresponsiveness. Thus, we have demonstrated a concise method to construct sequence-controlled bio-based copolymers with precisely adjustable structures and functions which can be applied to the design of biological and medical materials.
研究领域:
高分子化学
·
生物材料科学
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DOI
高影响因子
POLYMER
·
2018
·
IF 3.483
Pibo Liu,Hongwei Ma,Li Han,Lincan Yang,Heyu Shen,Chao Li,Yang Li
Three amine-functionalized 1,1-diphenylethylene (DPE) derivatives (DPE-(NMe 2 ) 2 , DPE-NMe 2 and DPE-SiH/NMe 2 ) were used to study the end-capping reactions of poly(styryl)lithium (PS-Li) for investigating the effect on end-capping of electron-donating groups in DPE structures. In situ 1 H NMR was used to measure the kinetic parameters of end-capping reactions. When the DPE derivative was held constant in the PS-Li capping reaction, the kinetic parameter (k SD ) did not change with the variance of either concentration or degree of polymerization of PS-Li. Additionally, the k SD value changed dramatically when various electronic properties of the DPE derivative substituents were modified. Electron-withdrawing groups accelerated the end-capping reaction, while electron-donating groups decelerated it. The k SD experimental values of DPE-(NMe 2 ) 2 , DPE-NMe 2 and DPE-SiH/NMe 2 were found to be 0.155 × 10 −3 , 1.26 × 10 −3 , and 6.24 × 10 −3 L 1/2 mol −1/2 s −1 , respectively. An intuitive model was established to simulate the precision of the sequence-controlled copolymerization with DPE derivatives based on investigations of end-capping kinetics. The model depicts the degree of fictitious styrene propagation for the chain insertion of one DPE derivative unit. The fictitious degrees of polymerization of styrene (FDPs) for DPE-NMe 2 and DPE-SiH/NMe 2 were calculated to be 37 and 13, respectively, suggesting that using DPE derivatives containing an electron-withdrawing group in the synthesis of sequence-controlled polymers might lead to a more precise structure.
研究领域:
高分子化学
·
材料科学
✓ 已验证
DOI
高影响因子
POLYMER
·
2019
·
IF 3.771
Chao-Ran Xu,Ze Zhang,Cai-Yuan Pan,Chun-Yan Hong
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.
研究领域:
化学
·
材料科学
✓ 已验证
DOI
高影响因子
POLYMER
·
2019
·
IF 3.771
Qingchi Ma,Li Han,Hongwei Ma,Pibo Liu,Heyu Shen,Lincan Yang,Chao Li,Xinyu Hao,Yang Li
Alternating copolymers consisting of a kind of mild electron-withdrawing 1,1-diphenylethylene (DPE) derivative and di-olefins, such as 1,1-bis(4-dimethylsilylphenyl)ethylene (DPE-2SiH) and isoprene (Ip), were successfully synthesized via anionic copolymerization using N,N,N′,N′ -tetramethylethylenediamine (TMEDA) as the modifier and benzene as the solvent. Two mild electron-withdrawing groups (binary -SiH) existed in this system. Therefore, the reaction activity of DPE-2SiH was higher than that of dimethyl-[4(1-phenylvinyl)phenyl]silane (DPE-SiH), and DPE-2SiH was expected to be an appropriate co-monomer for polymerization with dienes. The addition of TMEDA was found to not only control the resulting sequence but also regulate the contents of cis- and trans- structures in the Ip units. To further explore the mechanism of polymerizing DPE-2SiH and isoprene with and without the use of the TMEDA additive, the target samples were carefully characterized by SEC, 1 H NMR and in situ 1 H NMR. By examining the results, the apparent rate constants of DPE-2SiH and Ip without TMEDA were 1.19 × 10 −3 min −1 and 1.29 × 10 −2 min −1 , respectively, while those of DPE-2SiH and Ip with TMEDA were 4.47 × 10 −5 min −1 and 3.05 × 10 −5 min −1 , respectively. The reactivity ratios r Ip of isoprene with and without TMEDA were also calculated by the least square method and found to be 0.65 and 4.21, respectively, which illustrates the mechanisms of the copolymerization of DPE-2SiH and isoprene. By investigating the mechanism of the copolymerization process, the sequence can be controlled the alternating copolymerization, which can be facilely realized in a nonpolar solvent through the use of TMEDA. The alternating copolymers using this method have great significance both to regulation method of the microstructure of isoprene units and to the industrial production of functionalized materials. Then the alternating copolymers of DPE-2SiH and Ip were also applied to synthesize centipede-shaped grafted poly(isoprene)s (PIps). For the existence of bilateral -SiH groups in the chain, hydrosilylation of -SiH and alkynyl groups was performed at room temperature to avoid the unexpected reaction of the -SiH and alkenyl groups from the PIp branches.
研究领域:
高分子化学
·
材料科学
✓ 已验证
DOI
高影响因子
Polymer Chemistry
·
2016
·Vol. 7
·期 41
·6297-6308
·
IF 5.687
Xin Wang,Jiaqi Liu,Songquan Xu,Jiaxi Xu,Xianfu Pan,Jingjing Liu,Saide Cui,Zhenjiang Li,Kai Guo
Catalytic ring-opening polymerization (ROP) of the three major types of cyclic monomers, lactides, lactones, and carbonates, showed match and mismatch between the monomer and the catalyst. Therefore, one organocatalyst that works for all of the three in ROPs by a controlled/living nature is rare in ROPs. Herein, we proposed a traceless switch organocatalysis (TSOC) strategy and demonstrated it by switching from a Brønsted acid cationic to base/conjugate-acid bifunctional mechanisms in ROPs. Ring-opening copolymerization (ROCOP) of different types of monomers of lactones to lactides, and carbonates to lactides by organocatalysis was realized through an acid plus a base, i.e. “one plus one”, approach in one pot. The TSOC was exemplified by a methanesulfonic acid (MSA)/8-diazabicyclo[5.4.0]undec-7-ene (DBU) pair, and by diphenylphosphate (DPP)/DBU pair catalysis. DPP catalyzed cationic ROPs of δ-valerolactone (VL) and trimethylene carbonate (TMC); orthogonally, “DPP plus DBU” switched it into DPP/2DBU catalyzed bifunctional ROPs of L-lactide (LA), producing sequences of PVL-b-PLA, and PVL-b-PTMC-b-PLA. Alternatively, MSA catalyzed cationic ROPs of ε-caprolactone (CL) and TMC; switching it into MSA/2DBU catalyzed ROPs afforded block copolymers of PCL-b-PLA and PCL-b-PTMC-b-PLA. All the di- and triblock copolymers were characterized using 1H NMR, 13C NMR, and SEC; each showed its exact sequence length, predicted molecular weight, and narrow dispersity. An ROCOP of the three major types of carbonyl-containing cyclic monomers using a single organocatalysis platform, in one pot, via a traceless switch, and through multi-feeding of the monomers, to sequence controlled multiblock copolymers was fulfilled.
研究领域:
有机化学
·
高分子科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
MACROMOLECULES
·
2018
·
IF 5.914
Lincan Yang,Hongwei Ma,Li Han,Pibo Liu,Heyu Shen,Chao Li,Yang Li
Living anionic polymerization (LAP) is the primary representative method of living polymerization and exhibits the ability to synthesize sequence-regulated functionalized polymers. However, there has always been a lack of special features for LAP to guide these cutting-edge syntheses in sequence-controlled polymers. In this study, the copolymerizations of a series of alkyl-substituted 1,1-diphenylethylene derivatives (DPE-alkyls), which display similar reactivities but different structures, and St were performed. In addition, the processes of whole chain propagation were monitored by the in situ1H NMR method. The results show that changing the alkyl type of DPE-alkyls has little influence on their sequence distributions during copolymerization. Therefore, we could deduce a reasonable principle called “sequence equivalence” in LAP: the copolymers of different DPE derivatives and St would have identical sequence structures when DPE derivatives exhibit exactly the same reactivity ratio (rSt) during the copolymerization under the same conditions. Furthermore, the combination of in situ1H NMR experiments and kinetic Monte Carlo model (KMC) simulations was conducted synchronously. The results of simulations show that the KMC model not only can simulate detailed information for LAP of DPE derivative and St but also could quantify the precision of the corresponding sequence distributions. Additionally, the KMC model that we constructed for the simulation of sequence control in LAP can give us a new insight into the possibility of sequence tailoring. Next, the relationship among the glass transition temperatures (Tgs), types of alkyl substituent, and sequence structures of DPE derivative units in the chains was investigated. Through DSC analysis, this study’s results indicated that polymers with similar sequences but different alkyl substituents present contrasting differences in thermal property. These results could provide a broader understanding of the thermal properties of polymers.
研究领域:
高分子科学
·
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）