Laboratory for Biointerfaces, Empa, Swiss Federal Laboratories for Materials Science & Technology, Lerchenfeldstrasse 5, 9014, St. Gallen, Switzerland.
Department of Urology, Cantonal Hospital St. Gallen, Rorschacher Strasse 95, 9007, St. Gallen, Switzerland.
Adv Healthc Mater. 2019 Apr;8(8):e1801323. doi: 10.1002/adhm.201801323. Epub 2019 Feb 18.
The influence of mechanical stiffness of biomaterials on bacterial adhesion is only sparsely studied and the mechanism behind this influence remains unclear. Here, bacterial adhesion on polydimethylsiloxane (PDMS) samples, having four different degrees of stiffness with Young's modulus ranging from 0.06 to 4.52 MPa, is investigated. Escherichia coli and Pseudomonas aeruginosa are found to adhere in greater numbers on soft PDMS (7- and 27-fold increase, respectively) than on stiff PDMS, whereas Staphylococcus aureus adheres in similar numbers on the four tested surfaces. To determine whether the observed adhesion behavior is caused by bacteria-specific mechanisms, abiotic polystyrene (PS) beads are employed as bacteria substitutes. Carboxylate-modified PS (PS-COOH) beads exhibit the same adhesion pattern as E. coli and P. aeruginosa with four times more adhered beads on soft PDMS than on stiff PDMS. In contrast, amine-modified PS (PS-NH ) beads adhere in similar numbers on all tested samples, reminiscent of S. aureus adhesion. This work demonstrates for the first time that the intrinsic physicochemical properties associated with PDMS substrates of different stiffness strongly influence bacterial adhesion and challenge the previously reported theory on active bacterial mechanosensing, which provides new insights into the design of antifouling surfaces.
生物材料力学刚度对细菌黏附的影响研究甚少，其影响机制尚不清楚。在此，研究了黏附在具有从 0.06 到 4.52 MPa 不同杨氏模量的四种不同硬度的聚二甲基硅氧烷（PDMS）样品上的细菌黏附情况。与硬 PDMS 相比，大肠杆菌和铜绿假单胞菌在软 PDMS 上的黏附数量更多（分别增加了 7 倍和 27 倍），而金黄色葡萄球菌在四种测试表面上的黏附数量相似。为了确定观察到的黏附行为是否是由细菌特有的机制引起的，使用非生物聚苯乙烯（PS）珠作为细菌替代品。羧酸修饰的 PS（PS-COOH）珠表现出与大肠杆菌和铜绿假单胞菌相同的黏附模式，在软 PDMS 上黏附的珠子数量是硬 PDMS 的四倍。相比之下，胺修饰的 PS（PS-NH ）珠在所有测试样本上的黏附数量相似，类似于金黄色葡萄球菌的黏附。这项工作首次证明，与不同硬度 PDMS 基底相关的固有物理化学特性强烈影响细菌黏附，并挑战了先前关于细菌主动机械传感的报道理论，为抗污表面的设计提供了新的见解。
