Kozawa Susan K, Lord Audrey, Scott-McKean Jonah J, Walker Anne Y, Costa Alberto C S, Wnek Gary E
Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, OH 44106, USA.
Departments of Pediatrics and Psychiatry, Case Western Reserve University, Cleveland, OH 44106, USA.
Gels. 2021 Mar 30;7(2):37. doi: 10.3390/gels7020037.
Poly(acrylic acid) (PAA) bulk gels and threads, typically derived via free-radical polymerization, are of interest as anionic polyelectrolyte mimics of cellular cytosol and as models for early protocells. The thread dimensions have been limited by the diameters of readily-available glass or plastic capillaries, and threads with diameters of less than 50 µm have been difficult to achieve. Here, we report a useful approach for achieving crosslinked, partially neutralized PAA, namely poly(acrylate), gel threads with diameters of a few microns when dry. This technique utilizes coaxial electrospinning to effectively produce capillaries (shells) of polystyrene loaded with a gel-forming precursor mixture composed of 3 M acrylic acid, methylene-bisacrylamide, potassium persulfate and 2.2 M NaOH in the core, followed by thermally-induced polymerization and then the removal of the polystyrene shell. Relatively long (up to 5 mm), continuous PAA threads with thicknesses of 5-15 µm are readily obtained, along with a multitude of PAA gel particles, which result from the occasional break-up of the fluid core prior to gel formation during the electrospinning process. The threads and beads are of the sizes of interest to model ancient protocells, certain functional aspects of excitable cells, such as myocytes and neurons, and various membraneless organelles.
聚丙烯酸（PAA）本体凝胶和纤维通常通过自由基聚合得到，作为细胞胞质溶胶的阴离子聚电解质模拟物以及早期原始细胞的模型受到关注。纤维尺寸受易于获得的玻璃或塑料毛细管直径限制，直径小于50微米的纤维很难制备。在此，我们报道一种制备交联、部分中和的PAA（即聚丙烯酸盐）凝胶纤维的有效方法，干燥时其直径为几微米。该技术利用同轴静电纺丝有效地制备聚苯乙烯毛细管（壳层），其核心是由3M丙烯酸、亚甲基双丙烯酰胺、过硫酸钾和2.2M氢氧化钠组成的凝胶形成前体混合物，随后进行热诱导聚合，然后去除聚苯乙烯壳层。容易获得相对较长（长达5毫米）、厚度为5 - 15微米的连续PAA纤维，以及大量PAA凝胶颗粒，这些颗粒是在静电纺丝过程中凝胶形成前流体核心偶尔破裂产生的。这些纤维和珠子的尺寸对于模拟古代原始细胞、可兴奋细胞（如心肌细胞和神经元）的某些功能方面以及各种无膜细胞器具有重要意义。
