Abstract：
Bioengineering seeks to replicate biological tissues exploiting scaffolds often based on polymeric biomaterials. Digital light processing (DLP) has emerged as a potent technique to fabricate tissue engineering (TE) scaffolds. However, the scarcity of suitable biomaterials with desired physico-chemical properties along with processing capabilities limits DLP\'s potential. Herein, we introduce acrylate-endcapped urethane-based polymers (AUPs) for precise physico-chemical tuning while ensuring optimal computer-aided design/computer-aided manufacturing (CAD/CAM) mimicry. Varying the polymer backbone (i.e. poly(ethylene glycol) (PEG) versus poly(propylene glycol) (PPG)) and photo-crosslinkable endcap (i.e. di-acrylate versus hexa-acrylate), we synthesized a series of photo-crosslinkable materials labeled as UPEG2, UPEG6, UPPG2 and UPPG6. Comprehensive material characterization including physico-chemical and biological evaluations, was followed by a DLP processing parametric study for each material. The impact of the number of acrylate groups per polymer (2 to 6) on the physico-chemical properties was pronounced, as reflected by a reduced swelling, lower water contact angles, accelerated crosslinking kinetics, and increased Young\'s moduli upon increasing the acrylate content. Furthermore, the different polymer backbones also exerted a substantial effect on the properties, including the absence of crystallinity, remarkably reduced swelling behaviors, a slight reduction in Young\'s modulus, and slower crosslinking kinetics for UPPG vs UPEG. The mechanical characteristics of DLP-printed samples showcased the ability to tailor the materials\' stiffness (ranging from 0.4 to 5.3 MPa) by varying endcap chemistry and/or backbone. The in vitro cell assays confirmed biocompatibility of the material as such and the DLP-printed discs. Furthermore, the structural integrity of 3D scaffolds was preserved both in dry and swollen state. By adjusting the backbone chemistry or acrylate content, the post-swelling dimensions could be customized towards the targeted application. This study showcases the potential of these materials offering tailorable properties to serve many biomedical applications such as cartilage TE.
摘要：
生物工程试图利用通常基于聚合物生物材料的支架来复制生物组织。数字光处理（DLP）已成为制造组织工程（TE）支架的有效技术。然而,缺乏具有所需物理化学性质和加工能力的合适生物材料限制了DLP的潜力。在这里，我们引入丙烯酸酯封端的氨基甲酸酯基聚合物（AUP）进行精确的物理化学调整，同时确保最佳的计算机辅助设计/计算机辅助制造（CAD/CAM）模拟。改变聚合物主链(即,聚(乙二醇)(PEG)与聚(丙二醇)(PPG))和可光交联的封端(即,二丙烯酸酯与六丙烯酸酯),我们合成了一系列被标记为UPEG2、UPEG6、UPPG2和UPPG6的光交联材料。全面的材料表征，包括物理化学和生物学评估，然后对每种材料进行DLP处理参数研究。每个聚合物（2至6）的丙烯酸酯基团数量对物理化学性质的影响是明显的，如肿胀减少所反映的，较低的水接触角，加速交联动力学，并在增加丙烯酸酯含量时增加杨氏模量。此外，不同的聚合物骨架也对性能产生了实质性的影响，包括没有结晶度，显著减少肿胀行为，杨氏模量略有降低，UPPG与UPEG的交联动力学较慢。DLP打印样品的机械特性显示了通过改变端盖化学和/或骨架来调整材料刚度(范围从0.4到5.3MPa)的能力。体外细胞测定证实了材料本身和DLP打印的光盘的生物相容性。此外，在干燥和溶胀状态下，3D支架的结构完整性得以保留。通过调节主链化学或丙烯酸酯含量，可以针对目标应用定制膨胀后尺寸。这项研究展示了这些材料的潜力，提供可定制的特性，以服务于许多生物医学应用，如软骨TE。
