In this work, pH-sensitive hydrogel nanoparticles based on N-isopropyl acrylamide (NIPAM) and methacrylic acid (MAA) at various molar ratios, were synthesized and characterized in terms of physicochemical and biological properties. FTIR and ¹HNMR spectra confirmed the successful synthesis of the copolymer that formed nanoparticles. AFM images and FE-SEM micrographs showed that nanoparticles were spherical, but their round-shape was slightly compromised with MAA content; besides, the size of particles tends to decrease as MAA content increased. The hydrogels nanoparticles also exhibited an interesting pH-sensitivity, displaying changes in its particle size when changes in pH media occurred. Biological characterization results indicate that all the synthesized particles are non-cytotoxic to endothelial cells and hemocompatible, although an increase of MAA content leads to a slight increase in the hemolysis percentage. Therefore, the pH-sensitivity hydrogels may serve as a versatile platform as self-regulated drug delivery systems in response to environmental pH changes.

在这项工作中，合成了基于N-异丙基丙烯酰胺（NIPAM）和甲基丙烯酸（MAA）的pH敏感水凝胶纳米颗粒，并根据其理化和生物学特性对其进行了表征。FTIR和¹HNMR光谱证实了形成纳米颗粒的共聚物的成功合成。AFM图像和FE-SEM显微照片显示纳米颗粒为球形，但其圆形形状受MAA含量的影响较小；此外，随着MAA含量的增加，颗粒尺寸趋于减小。水凝胶纳米颗粒还表现出令人感兴趣的pH敏感性，当pH介质发生变化时，其粒径也会发生变化。生物学表征结果表明，尽管MAA含量增加导致溶血百分比略有增加，但所有合成的颗粒均对内皮细胞无细胞毒性且具有血液相容性。因此，pH敏感性水凝胶可作为通用平台，以响应环境pH的变化作为自我调节的药物输送系统。