Alternating Placement of <scp>d</scp>‐ and <scp>l</scp>‐Alanine Moieties in the Polymer Side‐Chains

Goswami, Krishna Gopal; Saha, Biswajit; Mete, Sourav; De, Priyadarsi

doi:10.1002/macp.201800398

Cited by 11 publications

(10 citation statements)

References 38 publications

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“…Similarly for P4 , the quaternary aromatic carbon (a) and methylene carbon (c) signals were appeared at 135.1 and 35.0 ppm, respectively (Figure S9B). Although it was reported that the copolymerization of an equimolar mixture of styrene and maleimide gave the alternating copolymer with the poly(styrene- alt -maleimide) backbone, our abovementioned studies also signified the alternating placement of monomers along the copolymer chains …”

Section: Resultsmentioning

confidence: 95%

“…Although it was reported that the copolymerization of an equimolar mixture of styrene and maleimide gave the alternating copolymer with the poly(styrene-alt-maleimide) backbone, 33 our abovementioned studies also signified the alternating placement of monomers along the copolymer chains. 34 The number average molecular weight (M n,GPC ) and dispersity (D̵ ) values of the copolymers were determined from the GPC study. Note that the free COOH groups of copolymers were converted to tert-butyl ester groups before using these in GPC analysis.…”

Section: H Nmr Study and Esi-ms Spectroscopy (Figures S6−s8)mentioning

confidence: 99%

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pH-Induced Amphiphilicity-Reversing Schizophrenic Aggregation by Alternating Copolymers

et al. 2019

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A series of copolymers with controlled monomer sequences are prepared via the reversible addition−fragmentation chain transfer polymerization of tert-butyl carbamate (Boc)-L-alanine (VBA) and Boc-L-alanyl-L-leucine-conjugated styrenic (VBD) monomers with L-alanine-appended maleimide (NMA). Monomer distribution in the copolymer is examined by both 1 H and 13 C NMR spectroscopy which eventually confirms an alternate placement of the different monomers throughout the polymer main chain in both the copolymerization systems: VBA−NMA and VBD−NMA. After the successful expulsion of the pendant Boc groups, the deprotected copolymers with free −NH 3 + and −COOH functionalities in the side chain show pHinduced solubility transition in the pH range 3−8. As signified from 1 H NMR analysis, this solubility transition is mainly associated with a pH-dependent schizophrenic core−shell alteration of the aggregated polymer structure in aqueous solution which is also supported by the dynamic light scattering measurements showing a variation of the hydrodynamic diameters of the aggregates at different solution pH values. Scanning electron microscopy and transmission electron microscopy further evidenced the schizophrenic nature of deprotected copolymers where significant morphological variations (from spherical micelles to vesicles or nearly wormlike aggregates) are obtained as a result of varying the solution pH value. The observed morphologies at different solution pH values are explained via computer simulations of a model chain with varying hydrophobicity of alternating side groups. Such schizophrenic morphological transitions of the deprotected copolymers enable us to investigate their drug encapsulation and sustained release behaviors depending on the pH of the aqueous solution. To the best of our knowledge, this is the first report where an alternating copolymer shows pH-induced schizophrenic morphological transition behavior.

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Section: Resultsmentioning

confidence: 95%

Section: H Nmr Study and Esi-ms Spectroscopy (Figures S6−s8)mentioning

confidence: 99%

pH-Induced Amphiphilicity-Reversing Schizophrenic Aggregation by Alternating Copolymers

et al. 2019

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“…The detailed characterization of the synthesized copolymers through 1 H NMR, 13 C NMR and size exclusion chromatography (SEC) can be found in our previous report . Herein, we utilized RAFT polymerization method to have the polymers with well-defined molecular weight, narrow dispersity ( Đ ) and defined chain ends . The polymers were designated according to the following example: when MF = MP and VBP = VBP750 , the copolymer was assigned as P(MP- alt -VBP750).…”

Section: Resultsmentioning

confidence: 99%

Self-Assembly of Amphiphilic Copolymers with Sequence-Controlled Alternating Hydrophilic–Hydrophobic Pendant Side Chains

Goswami

Mete

Chaudhury

et al. 2020

ACS Appl. Polym. Mater.

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To design versatile ordered nanomorphologies from the alternating sequence-controlled amphiphilic copolymers, in the current work, we have investigated the self-assembly behavior of a series of alternating copolymers, prepared through the reversible addition− fragmentation chain transfer (RAFT) polymerization of methoxy poly(ethylene glycol) (mPEG) functionalized styrene (VBP) and fatty acid attached maleimide (MF) monomers. The copolymers efficiently induced self-aggregation of the pendant side chains to afford both micelle and vesicle nanostructures in aqueous medium depending on the amphiphilicity of the side chains, as evident from dynamic light scattering (DLS) and transmission electron microscopy (TEM) analysis. The copolymers also induced thermoresponsive phase transition in water with lower critical solution temperatures (LCST) in the range of 69−88 °C depending on the mPEG side chain lengths, as determined from UV−vis spectroscopy. The hydrophobic dye and hydrophilic drug loading abilities of the synthesized copolymers were investigated using nile red and doxorubicin hydrochloride (DOX•HCl) as model compounds, respectively. The copolymers further formed reverse micelles in hexane owing to the presence of hydrophobic fatty acid pendants in the side chains, for which hexane is a good solvent. Additionally, the in vitro cytotoxicity study was performed for the synthesized alternating copolymers which revealed their nontoxic nature up to 500 μg/mL polymer concentration. Thus, the current work represents a fundamental strategy to construct biocompatible polymeric nanostructures from amphiphilic alternating copolymers, endowing noteworthy features for potential advantages.

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“…1 , the synthetic route depicts the synthesized block copolymer consisting of PEGMA and long-chain fatty acid repeating unit. RAFT polymerization was employed to obtain polymers with controlled molecular weight as well as a defined chain terminal, 37 herein we also have used RAFT polymerization technique to obtain core–shell lipid polymer hybrid nanoparticle for drug delivery application using CDSP as CTA. The homopolymer poly(PEGMA) was synthesized by using CTA and AIBN as a thermal initiator at a feed ratio of PEGMA : CDSP : AIBN = 50 : 1 : 0.25.…”

Section: Resultsmentioning

confidence: 99%

RAFT polymerization mediated core–shell supramolecular assembly of PEGMA-co-stearic acid block co-polymer for efficient anticancer drug delivery

2021

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Alternating Placement of d‐ and l‐Alanine Moieties in the Polymer Side‐Chains

Cited by 11 publications

References 38 publications

pH-Induced Amphiphilicity-Reversing Schizophrenic Aggregation by Alternating Copolymers

pH-Induced Amphiphilicity-Reversing Schizophrenic Aggregation by Alternating Copolymers

Self-Assembly of Amphiphilic Copolymers with Sequence-Controlled Alternating Hydrophilic–Hydrophobic Pendant Side Chains

RAFT polymerization mediated core–shell supramolecular assembly of PEGMA-co-stearic acid block co-polymer for efficient anticancer drug delivery

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