- An expeditious multigram-scale synthesis of lysine dendrigraft (DGL) polymers by aqueous n-carboxyanhydride polycondensation
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The synthesis and characterisation of new arborescent architectures of poly(L-lysine), called lysine dendrigraft (DGL) polymers, are described. DGL polymers were prepared through a multiple-generation scheme (up to generation 5) in a weakly acidic aqueous medium by polycondensing Nε- trifluoroacetyl-L-lysine-N-carboxyanhydride (Lys(Tfa)-NCA) onto the previous generation G(n-1) of DGL, which was used as a macroinitiator. The first generation employed spontaneous NCA polycondensation in water without a macroinitiator; this afforded lowmolecular-weight, linear poly(L-lysine) G1 with a polymerisation degree of 8 and a polydispersity index of 1.2. The spontaneous precipitation of the growing Nε-Tfa-protected polymer (GnP) ensures moderate control of the molecular weight (with unimodal distribution) and easy work-up. The subsequent alkaline removal of Tfa protecting groups afforded generation Gn of DGL as a free form (with 35-60% overall yield from NCA precursor, depending on the DGL generation) that was either used directly in the synthesis of the next generation (G(n+1)) or collected for other uses. Unprotected forms of DGL G1-G5 were characterised by size-exclusion chromatography, capillary electrophoresis and 1H NMR spectroscopy. The latter technique allowed us to assess the branching density of DGL, the degree of which (ca. 25%) turned out to be intermediate between previously described dendritic graft poly(L-lysines) and lysine dendrimers. An optimised monomer (NCA) versus macroinitiator (DGL G(n-1)) ratio allowed us to obtain unimodal molecular weight distributions with polydispersity indexes ranging from 1.3 to 1.5. Together with the possibility of reaching high molecular weights (with a polymerisation degree of ca. 1000 for G5) within a few synthetic steps, this synthetic route to DGL provides an easy, cost-efficient, multigram-scale access to dendritic polylysines with various potential applications in biology and in other domains.
- Collet, Helene,Souaid, Eddy,Cottet, Herve,Deratani, Andre,Boiteau, Laurent,Dessalces, Guy,Rossi, Jean-Christophe,Commeyras, Auguste,Pascal, Robert
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- On-POM Ring-Opening Polymerisation of N-Carboxyanhydrides
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The ring-opening polymerisation of α-amino acid N-carboxyanhydrides (NCAs) offers a simple and scalable route to polypeptides with predicted and narrow molecular weight distributions. Here we show how polyoxometalates (POMs)—redox-active molecular metal-oxide anions—can serve as inorganic scaffold initiators for such NCA polymerisations. This “On-POM polymerisation” strategy serves as an innovative platform to design hybrid materials with additive or synergistic properties stemming from the inorganic and polypeptide component parts. We have used this synthetic approach to synthesise a library of bactericidal poly(lysine)–POM hybrid derivatives that can be used to prevent biofilm formation. This versatile “On-POM polymerisation” method provides a flexible synthetic approach for combining inorganic scaffolds with amino acids, and the potential to tailor and improve the specificity and performance of hybrid antimicrobial materials.
- Soria-Carrera, Héctor,Franco-Castillo, Isabel,Romero, Pilar,Martín, Santiago,de la Fuente, Jesús M.,Mitchell, Scott G.,Martín-Rapún, Rafael
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supporting information
p. 3449 - 3453
(2021/02/05)
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- METHOD FOR PREPARATION OF N-CARBOXYANHYDRIDES
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The invention discloses a method for the preparation off N-carboxyanhydrides (NCAs) by reaction of amino acids with phosgene.(II)
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Page/Page column 11; 12; 13
(2020/05/12)
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- Synthesis and Characterization of Stimuli-Responsive Star-Like Polypept(o)ides: Introducing Biodegradable PeptoStars
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Star-like polymers are one of the smallest systems in the class of core crosslinked polymeric nanoparticles. This article reports on a versatile, straightforward synthesis of three-arm star-like polypept(o)ide (polysarcosine-block-polylysine) polymers, which are designed to be either stable or degradable at elevated levels of glutathione. Polypept(o)ides are a recently introduced class of polymers combining the stealth-like properties of the polypeptoid polysarcosine with the functionality of polypeptides, thus enabling the synthesis of materials completely based on endogenous amino acids. The star-like homo and block copolymers are synthesized by living nucleophilic ring opening polymerization of the corresponding N-carboxyanhydrides (NCAs) yielding polymeric stars with precise control over the degree of polymerization (Xn = 25, 50, 100), Poisson-like molecular weight distributions, and low dispersities (? = 1.06–1.15). Star-like polypept(o)ides display a hydrodynamic radius of 5 nm (μ2 –3m glutathione concentration. The disulfide cleavage yields the respective polymeric arms, which possess Poisson-like molecular weight distributions and low dispersities (? = 1.05–1.12). Initial cellular uptake and toxicity studies reveal that PeptoStars are well tolerated by HeLa, HEK 293, and DC 2.4 cells. (Figure presented.).
- Holm, Regina,Weber, Benjamin,Heller, Philipp,Klinker, Kristina,Westmeier, Dana,Docter, Dominic,Stauber, Roland H.,Barz, Matthias
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- Directed interactions of block copolypept(o) ides with mannose-binding receptors: Peptomicelles targeted to cells of the innate immune system
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Core-shell structures based on polypept(o)ides combine stealth-like properties of the corona material polysarcosine with adjustable functionalities of the polypeptidic core. Mannose-bearing block copolypept(o)ides (PSar-block-PGlu(OBn)) have been synthesized using 11-amino-3,6,9-trioxa-undecyl-2,3,4,6-tetra-O-acetyl-O-α-D-mannopyranoside as initiator in the sequential ring-opening polymerization of α-amino acid N-carboxyanhydrides. These amphiphilic block copolypept(o)ides self-assemble into multivalent PeptoMicelles and bind to mannose-binding receptors as expressed by dendritic cells. Mannosylated micelles showed enhanced cell uptake in DC 2.4 cells and in bone marrow-derived dendritic cells (BMDCs) and therefore appear to be a suitable platform for immune modulation.
- Heller, Philipp,Mohr, Nicole,Birke, Alexander,Weber, Benjamin,Reske-Kunz, Angelika,Bros, Matthias,Barz, Matthias
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- Revisiting secondary structures in NCA polymerization: Influences on the analysis of protected polylysines
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Two series (degree of polymerization: 20-200) of polylysines with Z and TFA protecting groups were synthesized, and their behavior in a range of analytical methods was investigated. Gel permeation chromatography of the smaller polypeptides reveals a bimodal distribution, which is lost in larger polymers. With the help of GPC, NMR, circular dichroism (CD), and MALDI-TOF, it was demonstrated that the bimodal distribution is not due to terminated chains or other side reactions. Our results indicate that the bimodality is caused by a change in secondary structure of the growing peptide chain that occurs around a degree of polymerization of about 15. This change in secondary structure interferes strongly with the most used analysis method for polymers - GPC - by producing a bimodal distribution as an artifact. After deprotection, the polypeptides were found to exhibit exclusively random coil conformation, and thus a monomodal GPC elugram was obtained. The effect can be explained by a 1.6-fold increase in the hydrodynamic volume at the coil-helix transition. This work demostrates that secondary structures need to be carefully considered when performing standard analysis on polypeptidic systems.
- Huesmann, David,Birke, Alexander,Klinker, Kristina,Tuerk, Stephan,Raeder, Hans Joachim,Barz, Matthias
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p. 928 - 936
(2014/03/21)
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- The behavior of poly(amino acids) containing l -cysteine and their block copolymers with poly(ethylene glycol) on gold surfaces
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Poly(ethylene glycol) (PEG) is often used to biocompatibilize surfaces of implantable biomedical devices. Here, block copolymers consisting of PEG and l-cysteine-containing poly(amino acid)s (PAA's) were synthesized as polymeric multianchor systems for the covalent attachment to gold surfaces or surfaces decorated with gold nanoparticles. Amino-terminated PEG was used as macroinitiator in the ring-opening polymerization, (ROP), of respective amino acid N-carboxyanhydrides (NCA's) of l-cysteine (l-Cys), l-glutamate (l-Glu), and l-lysine (l-Lys). The resulting block copolymers formed either diblock copolymers, PEG-b-p(l-Glux-co-l-Cysy) or triblock copolymers, PEG-b-p(l-Glu)x-b-p(l-Cys)y. The monomer feed ratio matches the actual copolymer composition, which, together with high yields and a low polydispersity, indicates that the NCA ROP follows a living mechanism. The l-Cys repeat units act as anchors to the gold surface or the gold nanoparticles and the l-Glu repeat units act as spacers for the reactive l-Cys units. Surface analysis by atomic force microscopy revealed that all block copolymers formed homogenous and pin-hole free surface coatings and the phase separation of mutually immiscible PEG and PAA blocks was observed. A different concept for the biocompatibilization of surfaces was followed when thiol-terminated p(l-Lys) homopolymer was first grafted to the surface and then covalently decorated with HOOC-CH2-PEG-b-p(Bz-l-Glu) polymeric micelles. Copyright
- Obeid, Rodolphe,Armstrong, Tracy,Peng, Xiaoju,Busse, Karsten,Kressler, Joerg,Scholz, Carmen
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p. 248 - 257
(2014/01/06)
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- N-trifluoroacyl lysine derivatives in the synthesis of L-lysyl-L-glutamic acid
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Conditions were developed for simultaneous preparation of N a-trifluoroacetyl-L-lysine and N α,N a-bis(trifluoroacetyl)-L-lysine at overall conversion of initial lysine monohydrochloride up to 82%. By reaction of dimethyl L-glutamate with N α,N a-bis(trifluoroacetyl)-L-lysyl chloride in the presence of triethylamine or with N α- carboxyanhydride of N a-trifluoroacetyl-L-lysine with subsequent removing protecting groups in the formed dipeptides by treating with water-ethanol solution of sodium hydroxide we obtained L-lysyl-L-glutamic acid. Physicochemical characteristics of samples obtained coincided with characteristics of L-lysyl-L-glutamic acid described in the literature thus suggesting that no racemization occurred either at the stage of peptide bond formation or at deprotection.
- Cherevin,Gulevich,Popova,Zubreichuk,Knizhnikov
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p. 1427 - 1431
(2008/09/16)
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