Malekzadeh Elham, Zhang Newby Bi-Min
Department of Chemical, Biomolecular, and Corrosion Engineering, The University of Akron, 200 East Buchtel Commons, Akron, Ohio 44325-3906, United States.
ACS Biomater Sci Eng. 2020 Dec 14;6(12):7051-7060. doi: 10.1021/acsbiomaterials.0c01376. Epub 2020 Nov 10.
Thermoresponsive polymers (TRP)s have been widely used for various applications from controlling membrane fouling in separation to cell/cell sheet harvesting in regenerative medicine. While poly(-isopropylacrylamide) (pNIPAAm) is the most commonly used TRP, less expensive and easily processed poly(vinyl methyl ether) (PVME) also shows a hydrophilic to hydrophobic transition at 32-35 °C, near physiological conditions. In this study, we investigated the processing conditions for retaining a stable layer of PVME thin film on silica surfaces via entrapment in a 3-aminopropyltriethoxysilane (APTES) network. In addition, the thermoresponsive behaviors (TRB) of the retained PVME films were evaluated. Blend thin films of PVME/APTES with 90:10 and 50:50 mass ratios were spin-coated from their solutions in ethanol under ambient conditions and then annealed in a vacuum oven at 40, 60, 80, or 120 °C for 1, 2, or 3 days. The annealed films were then thoroughly rinsed with room temperature water and then soaked in water for 3 days. Our results showed that annealing at a temperature of ≥40 °C was necessary for retaining a PVME film on the surface. The higher annealing temperature led to greater film retention, probably due to the formation of a tighter APTES network. Regardless of processing conditions, all retained PVME films showed TRB, determined by water contact angles below and above the transition temperature of PVME. Additionally, particle attachment and protein adsorption on retained PVME films showed lower attachment or adsorption at room temperature as compared to that at 37 °C, and a greater difference was observed for the 90:10 blend where more PVME was consisted. Furthermore, human mesenchymal stem cells attached and proliferated on the retained PVME surfaces at 37 °C and rapidly detached at room temperature. These results illustrated the potential applications of PVME surfaces as thermoresponsive supports for low-fouling applications and noninvasive cell harvesting.
热响应性聚合物（TRP）已被广泛应用于各种领域，从控制分离过程中的膜污染到再生医学中的细胞/细胞片收获。虽然聚（N-异丙基丙烯酰胺）（pNIPAAm）是最常用的TRP，但价格较低且易于加工的聚（乙烯基甲基醚）（PVME）在32-35°C（接近生理条件）下也表现出从亲水性到疏水性的转变。在本研究中，我们研究了通过包埋在3-氨丙基三乙氧基硅烷（APTES）网络中在二氧化硅表面保留稳定的PVME薄膜层的加工条件。此外，还评估了保留的PVME薄膜的热响应行为（TRB）。将质量比为90:10和50:50的PVME/APTES共混薄膜在环境条件下从其乙醇溶液中旋涂，然后在真空烘箱中于40、60、80或120°C退火1、2或3天。然后将退火后的薄膜用室温的水彻底冲洗，再在水中浸泡3天。我们的结果表明，在≥40°C的温度下退火对于在表面保留PVME薄膜是必要的。较高的退火温度导致薄膜保留率更高，这可能是由于形成了更紧密的APTES网络。无论加工条件如何，所有保留的PVME薄膜都表现出TRB，这通过PVME转变温度上下的水接触角来确定。此外，与37°C相比，保留的PVME薄膜上的颗粒附着和蛋白质吸附在室温下显示出较低的附着或吸附，对于含有更多PVME的90:10共混物观察到更大的差异。此外，人间充质干细胞在37°C下附着并在保留的PVME表面增殖，在室温下迅速脱离。这些结果说明了PVME表面作为低污染应用和非侵入性细胞收获的热响应性支持物的潜在应用。
