NUS Graduate School for Integrative Science and Engineering , National University of Singapore , Kent Ridge, 117576 , Singapore.
Department of Chemical and Biomolecular Engineering , National University of Singapore , 4 Engineering Drive 4 , 119260 , Singapore.
ACS Appl Mater Interfaces. 2018 Mar 7;10(9):7882-7891. doi: 10.1021/acsami.8b00666. Epub 2018 Feb 26.
An important challenge facing the application of implanted biomaterials for tissue engineering is the need to facilitate desirable tissue interactions with the implant while simultaneously inhibiting bacterial colonization, which can lead to implant-associated infection. In this study, we explore the relevance of the physical parameters of polyelectrolyte multilayers, such as surface charge, wettability, and stiffness, in tissue cell/surface and bacteria/surface interactions, and investigate the tuning of the multilayer architecture to differentially control such interactions. Polyions with different side-chain chemical structures were paired with polyethylenimine to assemble multilayers with parallel control over surface charge and wettability under controlled conditions. The multilayers can be successfully cross-linked to yield stiffer (the apparent Young's modulus was increased more than three times its original value) and more stable films while maintaining parallel control over surface charge and wettability. The initial adhesion and proliferation of 3T3 fibroblast cells were found to be strongly affected by surface charge and wettability on the non-cross-linked multilayers. On the other hand, these cells adhered and proliferated in a manner similar to those on the cross-linked multilayers (apparent Young's modulus ∼2 MPa), regardless of surface charge and wettability. In contrast, Staphylococcus aureus ( S. aureus) and Escherichia coli ( E. coli) adhesion was primarily controlled by surface charge and wettability on both cross-linked and non-cross-linked multilayers. In both cases, negative charge and hydrophilicity inhibited their adhesion. Thus, a surface coating with a relatively high degree of stiffness from covalent cross-linking coupled with negative surface charge and high wettability can serve as an efficient strategy to enhance host cell growth while resisting bacterial colonization.
用于组织工程的植入生物材料应用所面临的一个重要挑战是，需要促进组织与植入物的理想相互作用，同时抑制细菌定植，否则可能导致植入物相关感染。在这项研究中，我们探讨了聚电解质多层的物理参数（如表面电荷、润湿性和刚性）在组织细胞/表面和细菌/表面相互作用中的相关性，并研究了通过调整多层结构来差异化控制这些相互作用的方法。我们将具有不同侧链化学结构的聚离子与聚乙烯亚胺配对，在受控条件下组装具有平行控制表面电荷和润湿性的多层膜。这些多层膜可以成功交联，从而使刚性增加（其表观杨氏模量增加了三倍以上），且更稳定，同时保持对表面电荷和润湿性的平行控制。发现 3T3 成纤维细胞的初始黏附和增殖强烈受到非交联多层膜表面电荷和润湿性的影响。另一方面，无论表面电荷和润湿性如何，这些细胞都以类似于交联多层膜（表观杨氏模量约为 2MPa）的方式黏附和增殖。相比之下，金黄色葡萄球菌（S. aureus）和大肠杆菌（E. coli）的黏附主要由交联和非交联多层膜的表面电荷和润湿性控制。在这两种情况下，负电荷和亲水性都抑制了它们的黏附。因此，通过共价交联获得相对较高刚性的表面涂层，再加上负表面电荷和高润湿性，可以作为一种有效的策略来增强宿主细胞的生长，同时抵抗细菌定植。
