Synthesis of PEGylated poly(amino acid) pentablock copolymers and their self‐assembly

Abstract

Pentablock copolymers with an ABCBA architecture were synthesized by ring‐opening polymerization of N‐carboxyanhydrides of l‐leucine and γ‐benzyl l‐glutamate using an α, ω‐diamino poly(ethylene glycol) (PEG) as macroinitiator. Three different PEGs with molecular weights of 2000, 4600 and 10 000 Da were used and the poly(amino acid) (PAA) block lengths were set to a combined 10 and 40, respectively, repeat units for p(l‐Leu) and 40 repeat units for p(l‐Glu). The molecular architecture of the resulting pentablock copolymers was determined by the order of monomer addition. The living character of the N‐carboxyanhydride ring‐opening polymerization enables the formation of multiblock copolymers. The degree of polymerization for the PAA blocks matched the monomer/initiator ratio. A structural switch element, which controls the hydrophilicity of the pentablock copolymers, was incorporated in the form of the p(l‐Glu) blocks. The pentablock copolymers became water soluble after hydrolyzing the benzyl ester protective groups. The pentablock copolymers self‐assembled into polymeric aggregates ranging in size between 160 and 340 nm. Hydrogels formed readily if the central PEG block had a molecular weight of at least 4600 Da and the terminal A‐blocks consisted of p(l‐Leu). SEM images confirmed the size ranges of the polymeric aggregates and showed non‐distinct spherical aggregates. © 2016 Society of Chemical Industry

Impact of Cationic Charge Density and PEGylated Poly(amino acid) Tercopolymer Architecture on Their Use as Gene Delivery Vehicles. Part 1: Synthesis, Self‐Assembly, and DNA Complexation

“…As expected protected PAA tercopolymers cannot be dissolved directly in deionized water, therefore a nanoprecipitation method that was previously developed for PAA pentablock copolymers was applied . Effective diameters of all protected tercopolymers ranged between 84.4 and 132.3 nm (Table ).…”

“…NCAs of TFA‐ l ‐Lys and l ‐Leu were prepared as described in previously published work . Briefly, glassware and stir bars were dried at 145–155 °C for 24 h. TFA‐ l ‐Lys (2.0 g, 8.264 mmol, 1×), triphosgene (2.943 g, 9.917 mmol, 1.2×), and α‐pinene (2.360 g, 17.36 mmol, 2.1×) were dissolved in dry EtOAc (40 mL).…”

(AB)n Segmented Copolyetherimides for 4D Printing

“…Materials: Polyethylene glycol diamines with molecular weights of about 2000 and 8000 g mol −1 were synthesized from corresponding PEG diols via PEG-ditosylate intermediates in analogy to a known procedure. [37,38] Jeffamine ED-900 (o,o′-bis(2-aminopropyl)polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol, CAS-No: 65605-36-9) was purchased from Sigma Aldrich. [39] The molecular weights of PEG diamines were determined by titration against 0.1 m HCl solution as Mn = 1998 g mol -1 and Mn.…”

A robust affinity chromatography system based on ceramic monoliths coated with poly(amino acid)‐based polymeric constructs

“…The Fuchs-Farthing method as amended by Daly and Poche 26 was used to prepare the TFA-L-Lys NCA as described previously. [27][28][29] Briefly, glassware and stir bars were dried at 150°C for 24 h to ensure anhydrous conditions and typically all NCA syntheses were performed with 2 g of TFA-L-Lys. Specifically, TFA-L-Lys (2.0 g, 8.3 mmol), triphosgene (2.9 g, 9.9 mmol, 1.2 mol L -1 excess) and ⊍-pinene (2.4 g, 17.4 mmol, 2.1 mol L -1 excess) were dissolved in 55 mL of dry EthAc).…”