Department of Functional Materials for Medicine and Dentistry and Bavarian Polymer Institute, University of Würzburg, Pleicherwall 2, 97070, Würzburg, Germany.
Institute of Chemistry and Biotechnology (ICBT), Centre for Cell Biology and Tissue Engineering, Zurich University of Applied Sciences, Wädenswil, CH-8820, Switzerland.
Adv Healthc Mater. 2019 Apr;8(7):e1801544. doi: 10.1002/adhm.201801544. Epub 2019 Mar 20.
Melt electrowriting (MEW) is an emerging additive manufacturing technology that direct-writes low-micron diameter fibers into 3D scaffolds with high porosities. Often, the polymers currently used for MEW are hydrophobic thermoplastics that induce unspecific protein adsorption and subsequent uncontrolled cell adhesion. Here are developed a coating strategy for MEW scaffolds based on six-arm star-shaped NCO-poly(ethylene oxide-stat-propylene oxide) (sP(EO-stat-PO)). This permanently hydrophilizes the PCL through the formation of a hydrogel coating and minimizes unspecific interactions with proteins and cells. It also provides the option of simultaneous covalent attachment of bioactive molecules through reaction with isocyanates before these are hydrolyzed. Furthermore, a photoactivatable chemical functionalization is introduced that is not dependent on the time-limited window of isocyanate chemistry. For this, photo-leucine is covalently immobilized into the sP(EO-stat-PO) layer, resulting in a photoactivatable scaffold that enables the binding of sterically demanding molecules at any timepoint after scaffold preparation and coating and is decoupled from the isocyanate chemistry. A successful biofunctionalization of MEW scaffolds via this strategy is demonstrated with streptavidin and collagen as examples. This hydrogel coating system is a generic one that introduces flexible specific and multiple surface functionalization, potentially for a spectrum of polymers made from different manufacturing processes.
熔融电写入（MEW）是一种新兴的增材制造技术，可以将低微米直径的纤维直接写入具有高孔隙率的 3D 支架中。通常，用于 MEW 的聚合物是疏水性热塑性塑料，会诱导非特异性蛋白质吸附和随后的不受控制的细胞黏附。在这里，我们基于六臂星形 NCO-聚（氧化乙烯--stat-氧化丙烯）（sP（EO-stat-PO））开发了一种用于 MEW 支架的涂层策略。这通过形成水凝胶涂层使 PCL 永久亲水，并最大程度地减少与蛋白质和细胞的非特异性相互作用。它还提供了通过与异氰酸酯反应来同时共价附着生物活性分子的选择，然后再将其水解。此外，引入了一种不依赖于异氰酸酯化学限时窗口的光活化化学功能化。为此，将光亮氨酸共价固定到 sP（EO-stat-PO）层中，得到一种光活化支架，可在支架制备和涂层后的任何时间点结合空间要求高的分子，并且与异氰酸酯化学分离。通过该策略成功地对 MEW 支架进行了生物功能化，以链霉亲和素和胶原蛋白为例。这种水凝胶涂层系统是一种通用系统，可进行灵活的特定和多重表面功能化，可能适用于由不同制造工艺制成的一系列聚合物。
