Synthesis of poly(2-ethyl-2-oxazoline)-block-polypeptide copolymers by combination of ring-opening polymerization of oxazoline and polycondensation of activated urethane derivatives of α-amino acids

Karadag, Koksal; Yamada, Shuhei; Endō, Takeshi

doi:10.1007/s00289-018-2313-2

Cited by 9 publications

(10 citation statements)

References 40 publications

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“…In this study, poly(2-ethyl-2-oxazoline) with a terminal primary amine group, PEtOx-NH 2 , was successfully synthesized using the CROP technique. Mass spectrometry analysis of the PEtOx-NH 2 revealed a major mass distribution with Δ m / z = 99 Da mass spacing, which is consistent with the monomer unit mass of EtOx = 99.13 g/mol [43,48]. Using the EDC and Sulfo-NHS coupling method, the purified PEtOx-NH 2 was covalently conjugated to the protruding spikes on the surface of HBcAg VLNPs via carboxyl groups (Scheme 2).…”

Section: Discussionmentioning

confidence: 65%

“…PEtOx-NH 2 was synthesized by the cationic ring-opening polymerization (CROP) technique. A flame-dried borosilicate vial was charged with MeOTs initiator (0.5 mmol, 0.093 g, 75 μL), EtOx monomer (12.5 mmol, 1.24 g, 1.26 mL), and acetonitrile (2.5 mL) with a total monomer to initiator molar ratio of 25:1, as described by Karadag et al [48]. The vial was then capped and heated at 80 °C for 20 h with stirring.…”

Section: Methodsmentioning

confidence: 99%

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Shielding of Hepatitis B Virus-Like Nanoparticle with Poly(2-Ethyl-2-Oxazoline)

Fam

Chee

Yong

et al. 2019

IJMS

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Virus-like nanoparticles (VLNPs) have been studied extensively as nanocarriers for targeted drug delivery to cancer cells. However, VLNPs have intrinsic drawbacks, in particular, potential antigenicity and immunogenicity, which hamper their clinical applications. Thus, they can be eliminated easily and rapidly by host immune systems, rendering these nanoparticles ineffective for drug delivery. The aim of this study was to reduce the antigenicity of hepatitis B core antigen (HBcAg) VLNPs by shielding them with a hydrophilic polymer, poly(2-ethyl-2-oxazoline) (PEtOx). In the present study, an amine-functionalized PEtOx (PEtOx-NH2) was synthesized using the living cationic ring-opening polymerization (CROP) technique and covalently conjugated to HBcAg VLNPs via carboxyl groups. The PEtOx-conjugated HBcAg (PEtOx-HBcAg) VLNPs were characterized with dynamic light scattering and UV-visible spectroscopy. The colloidal stability study indicated that both HBcAg and PEtOx-HBcAg VLNPs maintained their particle size in Tris-buffered saline (TBS) at human body temperature (37 °C) for at least five days. Enzyme-linked immunosorbent assays (ELISA) demonstrated that the antigenicity of PEtOx-HBcAg VLNPs reduced significantly as compared with unconjugated HBcAg VLNPs. This novel conjugation approach provides a general platform for resolving the antigenicity of VLNPs, enabling them to be developed into a variety of nanovehicles for targeted drug delivery.

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Section: Discussionmentioning

confidence: 65%

Section: Methodsmentioning

confidence: 99%

Shielding of Hepatitis B Virus-Like Nanoparticle with Poly(2-Ethyl-2-Oxazoline)

Fam

Chee

Yong

et al. 2019

IJMS

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“…No racemization of the amino acid chiral center is observed. This method enables the efficient conversion of several amino acids bearing alkyl [17], allyl [18], and indolyl [19] groups, as well as protecting hydroxyl [20,21], sulfur-containing [17,22,23], ester [16], amide [20,24], and urethane [25][26][27] groups. It is important to note that L-tryptophan is converted into the corresponding urethane 2f, which can be used for the synthesis of poly(L-tryptophan) [19].…”

Section: Scheme 5 Synthesis Of the O-4-(nitrophenyl)urethane Derivatmentioning

confidence: 99%

Well-Defined Construction of Functional Macromolecular Architectures Based on Polymerization of Amino Acid Urethanes

Endō

Sudo

2020

Biomedicines

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Polypeptide synthesis was accomplished using the urethane derivatives of amino acids as monomers, which can be easily prepared, purified, and stored at ambient temperature without the requirement for special precautions. The urethanes of amino acids are readily synthesized by the N-carbamoylation of onium salts of amino acids using diphenyl carbonate (DPC). The prepared urethanes are then efficiently cyclized to produce amino acid N-carboxyanhydrides (NCAs). Thereafter, in the presence of primary amines, the ring-opening polymerization (ROP) of NCAs is initiated using the amines, to yield polypeptides with controlled molecular weights. The polypeptides have propagating chains bearing reactive amino groups and initiating chain ends endowed with functional moieties that originate from the amines. Aiming to benefit from these interesting characteristics of the polypeptide synthesis using the urethanes of amino acids, various macromolecular architectures containing polypeptide components have been constructed and applied as biofunctional materials in highly efficient antifouling coatings against proteins and cells, as biosensors for specific molecules, and in targeted drug delivery.

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“…Another macroinitiator that can be successfully used for block copolymerization is poly(2‐ethyl‐2‐oxazoline) ( PEtOx‐NH 2 ), whose chain end is functionalized by an amino group . As shown in Scheme , PEtOx‐NH 2 can be synthesized by the cationic ROP of 2‐ethyl‐2‐oxazoline.…”

Section: Preparation and Utilization Of O‐phenylurethanes Of Amino Acidsmentioning

confidence: 99%

“…Another macroinitiator that can be successfully used for block copolymerization is poly(2-ethyl-2-oxazoline) (PEtOx-NH 2 ), whose chain end is functionalized by an amino group. 12 As shown in Scheme 20, PEtOx-NH 2 can be synthesized by the cationic ROP of 2-ethyl-2-oxazoline. Because this cationic ROP proceeds in a living manner, the cationic propagating end can be used for its functionalization by adding nucleophiles, and in this case the chain end is treated with excess ethylenediamine to obtain PEtOx-NH 2 .…”

Section: Block Copolymerizationmentioning

confidence: 99%

Well‐defined, environment‐friendly synthesis of polypeptides based on phosgene‐free transformation of amino acids into urethane derivatives and their applications

Endō

Sudo

2019

Polymer International

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In this study, both naturally occurring and artificial amino acids were successfully transformed into the corresponding urethane derivatives using diphenyl carbonate. The urethanes thus prepared could be efficiently cyclized into amino acid N‐carboxyanhydrides (NCAs) without the requirement of phosgene. In addition, the presence of primary amines converted the urethane derivatives into NCAs and initiated the ring‐opening polymerization of the in situ formed NCAs, allowing for the well‐defined synthesis of polypeptides. These polypeptides contained initiating ends functionalized by an amine‐derived residue and propagating ends bearing the reactive amino group. By precise control of the structures of the polypeptides, various polypeptide conjugates such as block copolymers and graft copolymers were successfully synthesized as designed, and their applications in antifouling coatings against proteins, drug delivery systems and biosensors were demonstrated. © 2019 Society of Chemical Industry

show abstract

Synthesis of poly(2-ethyl-2-oxazoline)-block-polypeptide copolymers by combination of ring-opening polymerization of oxazoline and polycondensation of activated urethane derivatives of α-amino acids

Cited by 9 publications

References 40 publications

Shielding of Hepatitis B Virus-Like Nanoparticle with Poly(2-Ethyl-2-Oxazoline)

Shielding of Hepatitis B Virus-Like Nanoparticle with Poly(2-Ethyl-2-Oxazoline)

Well-Defined Construction of Functional Macromolecular Architectures Based on Polymerization of Amino Acid Urethanes

Well‐defined, environment‐friendly synthesis of polypeptides based on phosgene‐free transformation of amino acids into urethane derivatives and their applications

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