Spin labels as a probe of the molecular environment of covalently bound ligands in an hydrophobic and an hydrophilic polymer.
Spin labels as a probe of the molecular environment of covalently bound ligands in an hydrophobic and an hydrophilic polymer.
复制标题
自旋标记作为疏水性和亲水性聚合物中共价结合配体分子环境的探针。
DOI：
10.1016/0142-9612(91)90018-6
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发表时间：
1991
期刊：
影响因子：
14
通讯作者：
Chignell,CF
中科院分区：
文献类型：
--
作者：
Pitt,CG;Song,XC;Sik,R;Chignell,CF
The molecular motions of spin-labelled ligands covalently bound by spacer groups to an hydrophobic and an hydrophilic polymer matrix were evaluated by ESR spectroscopy. The ligands were prepared by alkylation of 4-N-methylamino-TEMPO with the ω-bromocarboxylic esters, Br(CH2)nCOOEt,n= 1,4 and 10. The hydrolysed esters were coupled to a cross-linked aminoethylated polyacrylamide hydrogel (n= 1,4,10) and to a surface hydroxylated elastomeric polyester (n= 4). The rotational correlation times (τc) of the nitroxide label in the hydrogels were measured in the dry state and after exposure to water at pH 4, 7.4 and 10.5. Theτcof the nitroxide label was insensitive to the length of the spacer group and to the degree of protonation of the tertiary amino group of the ligand. There was no evidence of self-association of the ligand and spacer, or more than a single phase within the polyacrylamide hydrogel. Theτcof the nitroxide labelled polyester was similarly insensitive to pH, but was sensitive to organic solvents. The low mobility of the spin label and its high concentration were consistent with the spin label being covalently bound within the hydrophobic polyester matrix to a depth of at least 5μ m.
