Cicotte Kirsten N, Reed Jamie A, Nguyen Phuong Anh H, De Lora Jacqueline A, Hedberg-Dirk Elizabeth L, Canavan Heather E
Biomedical Engineering Graduate Program, University of New Mexico, Albuquerque, New Mexico 87131; Department of Chemical and Biological Engineering, University of New Mexico, Albuquerque, New Mexico 87131; and Center for Biomedical Engineering, University of New Mexico, Albuquerque, New Mexico 87131.
Biomedical Engineering Graduate Program, University of New Mexico, Albuquerque, New Mexico 87131 and Center for Biomedical Engineering, University of New Mexico, Albuquerque, New Mexico 87131.
Biointerphases. 2017 Jun 13;12(2):02C417. doi: 10.1116/1.4984933.
Poly(N-isopropyl acrylamide) (pNIPAM) is a "smart" polymer that responds to changes in altering temperature near physiologically relevant temperatures, changing its relative hydrophobicity. Mammalian cells attach to pNIPAM at 37 °C and detach spontaneously as a confluent sheet when the temperature is shifted below the lower critical solution temperature (∼32 °C). A variety of methods have been used to create pNIPAM films, including plasma polymerization, self-assembled monolayers, and electron beam ionization. However, detachment of confluent cell sheets from these pNIPAM films can take well over an hour to achieve potentially impacting cellular behavior. In this work, pNIPAM mats were prepared via electrospinning (i.e., espNIPAM) by a previously described technique that the authors optimized for cell attachment and rapid cell detachment. Several electrospinning parameters were varied (needle gauge, collection time, and molecular weight of the polymer) to determine the optimum parameters. The espNIPAM mats were then characterized using Fourier-transform infrared, x-ray photoelectron spectroscopy, and scanning electron microscopy. The espNIPAM mats showing the most promise were seeded with mammalian cells from standard cell lines (MC3T3-E1) as well as cancerous tumor (EMT6) cells. Once confluent, the temperature of the cells and mats was changed to ∼25 °C, resulting in the extremely rapid swelling of the mats. The authors find that espNIPAM mats fabricated using small, dense fibers made of high molecular weight pNIPAM are extremely well-suited as a rapid release method for cell sheet harvesting.
聚（N-异丙基丙烯酰胺）（pNIPAM）是一种“智能”聚合物，在接近生理相关温度的变化温度下会发生响应，改变其相对疏水性。哺乳动物细胞在37°C时附着于pNIPAM，当温度降至低临界溶液温度（约32°C）以下时，会作为汇合片自发脱离。已经使用了多种方法来制备pNIPAM膜，包括等离子体聚合、自组装单分子层和电子束电离。然而，汇合细胞片从这些pNIPAM膜上脱离可能需要一个多小时才能实现，这可能会影响细胞行为。在这项工作中，通过静电纺丝制备了pNIPAM垫（即espNIPAM），采用了作者之前描述的一种技术，该技术针对细胞附着和快速细胞脱离进行了优化。改变了几个静电纺丝参数（针规、收集时间和聚合物分子量）以确定最佳参数。然后使用傅里叶变换红外光谱、X射线光电子能谱和扫描电子显微镜对espNIPAM垫进行表征。将最有前景的espNIPAM垫接种来自标准细胞系（MC3T3-E1）的哺乳动物细胞以及癌性肿瘤（EMT6）细胞。一旦汇合，将细胞和垫的温度改变至约25°C，导致垫极快速膨胀。作者发现，使用由高分子量pNIPAM制成的小而致密的纤维制造的espNIPAM垫非常适合作为细胞片收获的快速释放方法。
