PDF(Pubmed)
Abstract：
Monodispersed polyethylene glycol diacrylate (PEGDA)/acrylic acid (AA) microgels with a tuneable negative charge and macroporous internal structure have been produced using a Lego-inspired droplet microfluidic device. The surface charge of microgels was controlled by changing the content of AA in the monomer mixture from zero (for noncharged PEGDA beads) to 4 wt%. The macroporosity of the polymer matrix was introduced by adding 20 wt% of 600-MW polyethylene glycol (PEG) as a porogen material into the monomer mixture. The porogen was successfully leached out with acetone after UV-crosslinking, which resulted in micron-sized cylindrical pores with crater-like morphology, uniformly arranged on the microgel surface. Negatively charged PEGDA/AA beads showed improved adsorption capacity towards positively charged organic dyes (methylene blue and rhodamine B) compared to neutral PEGDA beads and high repulsion of negatively charged dye molecules (methyl orange and congo red). Macroporous microgels showed better adsorption properties than nonporous beads, with a maximum adsorption capacity towards methylene blue of 45 mg/g for macroporous PEGDA/AA microgels at pH 8.6, as compared to 23 mg/g for nonporous PEGDA/AA microgels at the same pH. More than 98% of Cu(II) ions were removed from 50 ppm solution at pH 6.7 using 2.7 mg/mL of macroporous PEGDA/AA microgel. The adsorption of cationic species was significantly improved when pH was increased from 3 to 9 due to a higher degree of ionization of AA monomeric units in the polymer network. The synthesized copolymer beads can be used in drug delivery to achieve improved loading capacity of positively charged therapeutic agents and in tissue engineering, where a negative charge of scaffolds coupled with porous structure can help to achieve improved permeability of high-molecular-weight metabolites and nutrients, and anti-fouling activity against negatively charged species.
摘要：
已使用Lego启发的液滴微流体装置生产了具有可调负电荷和大孔内部结构的单分散聚乙二醇二丙烯酸酯（PEGDA）/丙烯酸（AA）微凝胶。通过将单体混合物中AA的含量从零（对于不带电荷的PEGDA珠）改变为4wt％来控制微凝胶的表面电荷。通过将20wt%的600-MW聚乙二醇(PEG)作为致孔剂材料添加到单体混合物中来引入聚合物基质的大孔隙率。UV交联后，致孔剂成功地用丙酮浸出，这导致了微米大小的圆柱形孔，具有火山口状的形态，均匀排列在微凝胶表面。与中性PEGDA珠相比，带负电荷的PEGDA/AA珠对带正电荷的有机染料（亚甲基蓝和罗丹明B）的吸附能力提高，对带负电荷的染料分子（甲基橙和刚果红）的排斥作用很高。大孔微凝胶比无孔微珠表现出更好的吸附性能，在pH8.6时，大孔PEGDA/AA微凝胶对亚甲基蓝的最大吸附能力为45mg/g，而在相同pH下，无孔PEGDA/AA微凝胶为23mg/g。使用2.7mg/mL的大孔PEGDA/AA微凝胶从pH6.7的50ppm溶液中去除超过98%的Cu(II)离子。当pH从3增加到9时，由于聚合物网络中AA单体单元的电离程度更高，阳离子物种的吸附显着提高。合成的共聚物珠可用于药物递送以实现带正电荷的治疗剂的改进的负载能力和组织工程,其中支架的负电荷与多孔结构耦合可以帮助实现高分子量代谢物和营养素的改善渗透性，和对抗带负电荷的物种的防污活性。
