Department of Biomedical Engineering, National University of Singapore, Singapore; Mechanobiology Institute, National University of Singapore, Singapore.
Department of Biomedical Engineering, National University of Singapore, Singapore; Institute of Materials Research and Engineering, Agency for Science, Technology and Research, Singapore.
Biomaterials. 2016 Apr;84:184-195. doi: 10.1016/j.biomaterials.2016.01.036. Epub 2016 Jan 20.
Poly(vinyl alcohol) hydrogel (PVA) is a widely used material for biomedical devices, yet there is a need to enhance its biological functionality for in vitro and in vivo vascular application. Significance of surface topography in modulating cellular behaviour is increasingly evident. However, hydrogel patterning remains challenging. Using a casting method, planar PVA were patterned with micro-sized features. To achieve higher patterning resolution, nanoimprint lithography with high pressure and temperature was used. In vitro experiment showed enhanced human endothelial cell (EC) density and adhesion on patterned PVA. Additional chemical modification via nitrogen gas plasma on patterned PVA further improved EC density and adhesion. Only EC monolayer grown on plasma modified PVA with 2 μm gratings and 1.8 μm concave lens exhibited expression of vascular endothelial cadherin, indicating EC functionality. Patterning of the luminal surface of tubular hydrogels is not widely explored. The study presents the first method for simultaneous tubular molding and luminal surface patterning of hydrogel. PVA graft with 2 μm gratings showed patency and endothelialization, while unpatterned grafts were occluded after 20 days in rat aorta. The reproducible, high yield and high-fidelity methods enable planar and tubular patterning of PVA and other hydrogels to be used for biomedical applications.
聚乙烯醇水凝胶 (PVA) 是一种广泛应用于生物医学设备的材料，但需要提高其生物功能，以满足体外和体内血管应用的需求。表面形貌在调节细胞行为方面的重要性越来越明显。然而，水凝胶的图案化仍然具有挑战性。本研究使用浇铸法对平面 PVA 进行微尺度特征图案化。为了实现更高的图案化分辨率，采用了高压和高温的纳米压印光刻技术。体外实验表明，图案化 PVA 上的人内皮细胞 (EC) 密度和黏附性得到增强。通过氮气等离子体对图案化 PVA 进行进一步的化学修饰，进一步提高了 EC 的密度和黏附性。只有在经过等离子体修饰的、具有 2μm 光栅和 1.8μm 凹透镜图案的 PVA 上生长的单层 EC 表达了血管内皮钙黏蛋白，表明 EC 具有功能。管状水凝胶的管腔表面图案化尚未得到广泛探索。本研究提出了一种同时对水凝胶进行管状成型和管腔表面图案化的新方法。带有 2μm 光栅的 PVA 接枝物显示出通畅性和内皮化，而未经图案化的接枝物在大鼠主动脉中 20 天后被阻塞。这种可重复、高产率和高保真度的方法能够对 PVA 和其他水凝胶进行平面和管状图案化，从而应用于生物医学领域。
