RAFT Polymer End-Group Modification and Chain Coupling/Conjugation Via Disulfide Bonds

2009 ◽  
Vol 62 (8) ◽  
pp. 830 ◽  
Author(s):  
Cyrille Boyer ◽  
Jingquan Liu ◽  
Volga Bulmus ◽  
Thomas P. Davis
Keyword(s):  
Disulfide Bonds ◽  
Diblock Copolymers ◽  
Raft Polymerization ◽  
Gel Permeation Chromatography ◽  
Reversible Addition ◽  
Group Modification ◽  
End Groups ◽  
End Group Modification ◽  
High Yields ◽  
End Group

End-group modification of polymers prepared by reversible addition–fragmentation chain transfer (RAFT) polymerization was accomplished by the conversion of trithiocarbonate or dithioester end-groups into a pyridyl disulfide (PDS) functionality. Several different polymers, such as poly(methyl methacrylate), polystyrene, poly(oligoethylene glycol-acrylate), poly(hydroxypropylacrylamide), and poly(N-isopropylacrylamide) were prepared by RAFT polymerization, and subjected to aminolysis in the presence of 2,2′-dithiodipyridine to yield thiol-terminated polymers with yields in the range 65–90% dependent on the polymer structure. Furthermore, this PDS end-group was utilized to generate higher-order architectures, such as diblock copolymers with high yields and selectively. In addition, the PDS end-groups were used for the bioconjugation of different biomolecules, such as oligonucleotides, carbohydrates, and peptides. The successful modification of well-defined polymers was confirmed by a combination of UV-vis, NMR spectroscopy, and gel permeation chromatography.

scholarly journals Fabrication of Polymer Micelles with Zwitterionic Shell and Biodegradable Core for Reductively Responsive Release of Doxorubicin

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1019 ◽  
Author(s):  
Junting Jiang ◽  
Junbo Li ◽  
Biyu Zhou ◽  
Chaohuang Niu ◽  
Wendi Wang ◽  
...  
Keyword(s):  
Drug Release ◽  
Disulfide Bonds ◽  
High Stability ◽  
Polymeric Micelles ◽  
Raft Polymerization ◽  
Drug Efficacy ◽  
Low Protein ◽  
Self Assembling ◽  
Group Modification ◽  
End Group Modification

To achieve a high stability in physiological environment and rapid intracellular drug release, a biodegradable zwitterionic triblock copolymer with a disulfide-linked poly-ε-caprolactone and polycarboxybetaine methacrylate (PCBMA-SS-PCL-SS-PCBMA) was prepared for micellar carrier to delivery doxorubicin (DOX) into tumor cells. PCBMA-SS-PCL-SS-PCBMA was obtained by following steps: i) introducing disulfide bonds through end-group modification of PCL diol with cystamine dihydrochloride; ii) preparing PCL-RAFT macromolecular chain transfer agent by EDC/NHS chemistry; iii) RAFT polymerization of zwitterionic monomer. Self-assembling from PCBMA-SS-PCL-SS-PCBMA, polymeric micelles had many advantages, such as ultra-low protein absorption in serum and obvious reduction-responsiveness in the presence of DTT. Furthermore, DOX-loaded micelles exhibited high stability upon centrifugation and lyophilization, a fast intracellular drug release and enhanced drug efficacy due to GSH-triggered PCBMA shell shedding and micellar reassembling. Thus, the polymeric micelles integrated several functions and properties could be prospectively utilized as valuable nanocarriers in cancer chemotherapeutics.

scholarly journals Effective End-Group Modification of Star-Shaped PNVCL from Xanthate to Trithiocarbonate Avoiding Chemical Crosslinking

Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3677
Author(s):  
Norma A. Cortez-Lemus ◽  
Eduardo Hermosillo-Ochoa ◽  
Ángel Licea-Claverie
Keyword(s):  
Raft Polymerization ◽  
Benzyl Bromide ◽  
Star Polymers ◽  
Solution Concentration ◽  
Hydrodynamic Diameter ◽  
Reversible Addition ◽  
Yellow Color ◽  
Group Modification ◽  
End Group Modification ◽  
Responsive Behavior

In this study, six-arm star-shaped poly(N-vinylcaprolactam) (PNVCL) polymers prepared by reversible addition–fragmentation chain transfer (RAFT) polymerization were subjected to aminolysis reaction using hexylamine. Chemically crosslinked gels or highly end-functionalized star polymers can be obtained depending mainly on the type of solvent used during the transformation of the RAFT functional group. An increase in the viscosity of the solution was observed when the aminolysis was carried out in THF. In contrast, when the reaction was conducted in dichloromethane, chain-end thiol (PNVCL)6 star polymers could be obtained. Moreover, when purified (PNVCL-SH)6 star polymers are in contact with THF, the gelation occurs in just a few minutes, with an obvious increase in viscosity, to form physical gels that become chemically crosslinked gels after 12 h. Interestingly, when purified (PNVCL-SH)6 star polymers were stirred in distilled water, even at high aqueous solution concentration (40 mg/mL), there was no increase in the viscosity or gelation, and no evident gels were observed. The analysis of the hydrodynamic diameter (Dh) by dynamic light scattering (DLS) did not detect quantifiable change even after 4 days of stirring in water. On the other hand, the thiol groups in the (PNVCL-SH)6 star polymers were easily transformed into trithiocarbonate groups by addition of CS2 followed by benzyl bromide as demonstrated by UV-Vis spectroscopical analysis and GPC. After the modification, the (PNVCL)6 star polymers exhibit an intense yellow color typical of the absorption band of trithiocarbonate group at 308 nm. To further demonstrate the highly effective new trithiocarbonate end-functionality, the PNVCL polymers were successfully chain extended with N-isopropylacrylamide (NIPAM) to form six-arm star-shaped PNIPAM-b-PNVCL block copolymers. Moreover, the terminal thiol end-functionality in the (PNVCL-SH)6 star polymers was linked via disulfide bond formation to l-cysteine to further demonstrate its reactivity. Zeta potential analysis shows the pH-responsive behavior of these star polymers due to l-cysteine end-functionalization. By this using methodology and properly selecting the solvent, various environment-sensitive star polymers with different end-groups could be easily accessible.

New Polymer Syntheses. 103. In Situ End Group Modification of Hyperbranched Poly(3,5-dihydroxybenzoate)

1999 ◽  
Vol 32 (12) ◽  
pp. 3878-3882 ◽  
Author(s):  
Hans R. Kricheldorf ◽  
Oliver Bolender ◽  
Thomas Wollheim
Keyword(s):  
Hyperbranched Poly ◽  
Group Modification ◽  
End Group Modification ◽  
End Group

Macromolecular thiolysis of oxiranes: end-group modification of RAFT prepared homopolymers

2011 ◽  
Vol 2 (6) ◽  
pp. 1347 ◽  
Author(s):  
M. Alyse Harvison ◽  
Thomas P. Davis ◽  
Andrew B. Lowe
Keyword(s):  
Group Modification ◽  
End Group Modification ◽  
End Group

scholarly journals Doubly Dynamic Hydrogel Formed by Combining Boronate Ester and Acylhydrazone Bonds

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 487
Author(s):  
Yusheng Liu ◽  
Yigang Liu ◽  
Qiuxia Wang ◽  
Yugui Han ◽  
Hao Chen ◽  
...  
Keyword(s):  
Mechanical Property ◽  
Diblock Copolymers ◽  
Raft Polymerization ◽  
Solid Content ◽  
Self Healing ◽  
Covalent Bonds ◽  
Boronate Ester ◽  
Isopropyl Acrylamide ◽  
Reversible Addition ◽  
The Difference

The incorporation of double dynamic bonds into hydrogels provides an effective strategy to engineer their performance on demand. Herein, novel hydrogels were PREPARED by combining two kinetically distinct dynamic covalent bonds, boronate ester and acylhydrazone bonds, and the synergistic properties of the hydrogels were studied comprehensively. The functional diblock copolymers P(N-isopropyl acrylamide-co-N-acryloyl-3-aminophenylboronic acid)-b-(N-isopropyl acrylamide-co-diacetone acrylamide) (PAD) were prepared via reversible addition−fragmentation chain transfer (RAFT) polymerization. The hydrogel was constructed by exploiting dynamic reaction of phenyboronic acid moieties with polyvinyl alcohol (PVA) and ketone moieties with adipic dihydrazide (ADH) without any catalyst. The active boronate ester linkage endows the hydrogel with fast gelation kinetics and self-healing ability, and the stable acylhydrazone linkage can enhance the mechanical property of the hydrogel. The difference in kinetics endows that the contribution of each linkage to mechanical strength of the hydrogel can be accurately estimated. Moreover, the mechanical property of the hydrogel can be readily engineered by changing the composition and solid content, as well as by controlling the formation or dissociation of the dynamic linkages. Thus, we provide a promising strategy to design and prepare multi-responsive hydrogels with tunable properties.

Effect of end-group modification of poly(lactide)s by cinnamoyl chloride on their thermal stability

2017 ◽  
Vol 141 ◽  
pp. 97-103 ◽  
Author(s):  
Yuushou Nakayama ◽  
Naoki Matsubara ◽  
Zhennguo Cai ◽  
Takeshi Shiono ◽  
Kei Inumaru ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Group Modification ◽  
Cinnamoyl Chloride ◽  
End Group Modification ◽  
End Group

End group modification of polyamide-6 in supercritical and subcritical fluids

2004 ◽  
Vol 31 (1) ◽  
pp. 75-87 ◽  
Author(s):  
J.M. de Gooijer ◽  
J. Ellmann ◽  
M. Möller ◽  
C.E. Koning
Keyword(s):  
Polyamide 6 ◽  
Group Modification ◽  
End Group Modification ◽  
Subcritical Fluids ◽  
End Group
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