Synthesis and characterization of nanoscale biomimetic polymer vesicles and polymer membranes for bioelectronic applications
Synthesis and characterization of nanoscale biomimetic polymer vesicles and polymer membranes for bioelectronic applications
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DOI：
10.1088/0957-4484/16/5/002
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发表时间：
2005-05-01
期刊：
影响因子：
3.5
通讯作者：
Montemagno, CD
中科院分区：
文献类型：
--
作者：
Choi, HJ;Brooks, E;Montemagno, CD
以聚（2-乙基-2-恶唑啉）（PEtOz）为亲水嵌段[A]，聚二甲基硅氧烷（PDMS）为疏水嵌段[B]，合成了两亲性阿坝三嵌段共聚物。以氯化苄为引发剂，在碘化钠存在下，进行了2-乙基-2-恶唑啉的阳离子开环聚合。使用透射电子显微镜（TEM）在水溶液中表征PEtOz-PDMS-PEtOz。嵌段共聚物形成了[B]嵌段疏水组分厚度为4 nm的囊泡，该厚度足够薄，可以成功重建蛋白质。囊泡的平均直径被测量为在150-250 nm的范围内，具有窄分布。采用电化学阻抗谱（EIS）研究了平面PEtOz-PDMS-PEtOz膜在聚四氟乙烯孔上的电化学性能。阻抗数据显示，平面膜电容（C-MEM）从2.58 x 10（-7）增加到2.71 x 10（-7）F cm（-2），膜电阻（R-MEM）从12 Ω cm（2）降低到10.8 Ω cm（2）。CMEM在缓冲溶液中随时间的增加可以通过作为膜电解质掺入的结果的介电常数的增加和/或通过自支撑膜中缺陷的形成和生长来解释。与薄壁囊泡的形成相反，铺展的三嵌段共聚物形成了具有9 nm厚度的独立膜。基于三嵌段共聚物可能具有的两种构象（桥中间嵌段构象和环中间嵌段构象），我们可以得出结论：PEtOz-PDMS-PEtOz在水溶液中形成4 nm厚的具有插层环中间嵌段结构的聚合物囊泡，而9 nm厚的具有双层环中间嵌段构象或桥中间嵌段构象的自支撑聚合物膜通过孔径扩展形成。
An amphiphilic ABA triblock copolymer was synthesized using poly(2-ethyl-2-oxazoline) (PEtOz) as hydrophilic block [A] and poly(dimethylsiloxane) (PDMS) as hydrophobic block [B]. The cationic ring-opening polymerization of 2-ethyl-2-oxazoline was initiated by benzyl chloride in the presence of NaI. PEtOz-PDMS-PEtOz was characterized in aqueous solution using transmission electron microscopy (TEM). The block copolymers formed vesicles with a [B] block hydrophobic component thickness of 4 nm, which is thin enough for successful reconstitution of proteins. The mean diameters of the vesicles were measured to be in the range of 150-250 nm, with a narrow distribution. The electrochemical properties of planar PEtOz-PDMS-PEtOz membrane films spread across a Teflon aperture were investigated by electrochemical impedance spectroscopy (EIS). The impedance data showed an increase of planar membrane capacitance (C-MEM) from 2.58 x 10(-7) to 2.71 x 10(-7) F cm(-2) and a decrease of membrane resistance (R-MEM) from 12 to 10.8 Omega cm(2). The increase Of CMEM over time in buffer solution can be explained by an increase of the dielectric constant as a result of membrane electrolyte incorporation and/or by the formation and growth of defect in the free-standing films. In contrast to the formation of thin-walled vesicles, the spread triblock copolymer formed a free-standing membrane with a 9 nm thickness. Based on the two possible conformations (bridge midblock conformation and loop midblock conformation) that the triblock copolymer can have, we can conclude that PEtOz-PDMS-PEtOz formed 4 nm thick polymer vesicles with intercalated loop midblock structure in aqueous solution, while 9 nm thick free-standing polymer films with bilayer loop midblock conformation or with bridge midblock conformation were formed by aperture spreading.