Seelbach Ryan J, D'Este Matteo, Alini Mauro, Mata Alvaro, Eglin David
AO Research Institute Davos, Clavadelerstrasse, Davos Platz, Switzerland.
Universitat de Barcelona, Martí i Franquès, Barcelona, Spain.
Clin Hemorheol Microcirc. 2015;60(1):25-37. doi: 10.3233/CH-151933.
Poly(N-isopropylacrylamide) conjugated hyaluronan (HA-pN), a brush-like copolymer system which serves as a polymer vehicle for cellular and drug delivery, has been previously synthesized via the copper catalyzed azide-alkyne reaction (CuAAC) using a combination of copper sulfate and ascorbic acid (CuAsc) as the catalytic system of choice. Bromotris(triphenylphosphine) copper(I) (CuBr(PPh3)3) is an alternative catalytic compound containing a phosphorous ligand which stabilizes copper in the +1 oxidative state in aqueous solvents and can be employed at true catalyst concentrations.
CuAsc and CuBr(PPh3)3 were compared for their efficiency; 1) in the synthesis of HA-pN via CuAAC; 2) in producing thermoresponsive compositions and 3) in being extracted from the polymeric compositions.
The synthesis of the brush copolymer was carried out under strict Schlenk conditions, then characterized by ATR-FTIR, 1H NMR, ICP-SFMS, and rheological measurements.
CuBr(PPh3)3 catalyzed CuAAC leads to better grafting in water, at a true catalyst concentration, compared to CuAsc. Polymeric solutions exhibited similar traits of increasing mechanical stiffness with rising temperature. Despite purification via chelation and/or dialysis, residual copper was present in similar concentrations in the final polymers.
In the CuAAC driven copolymer synthesis of the HA-pN, CuBr(PPh3)3 is a better catalyst than CuAsc.
聚（N-异丙基丙烯酰胺）共轭透明质酸（HA-pN）是一种刷状共聚物体系，用作细胞和药物递送的聚合物载体，此前已通过铜催化的叠氮化物-炔烃反应（CuAAC），使用硫酸铜和抗坏血酸（CuAsc）的组合作为首选催化体系合成。溴三（三苯基膦）铜（I）（CuBr(PPh3)3）是一种替代催化化合物，含有磷配体，可在水性溶剂中将铜稳定在 +1 氧化态，并且可以在真正的催化剂浓度下使用。
比较 CuAsc 和 CuBr(PPh3)3 在以下方面的效率：1）通过 CuAAC 合成 HA-pN；2）制备热响应性组合物；3）从聚合物组合物中提取。
在严格的施伦克条件下进行刷状共聚物的合成，然后通过 ATR-FTIR、1H NMR、ICP-SFMS 和流变学测量进行表征。
与 CuAsc 相比，在真正的催化剂浓度下，CuBr(PPh3)3 催化的 CuAAC 在水中导致更好的接枝。聚合物溶液表现出随着温度升高机械刚度增加的相似特性。尽管通过螯合和/或透析进行了纯化，但最终聚合物中残留铜的浓度相似。
在 CuAAC 驱动的 HA-pN 共聚物合成中，CuBr(PPh3)3 是比 CuAsc 更好的催化剂。
