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Bacterial Adhesion to Graphene Oxide (GO)-Functionalized Interfaces Is Determined by Hydrophobicity and GO Sheet Spatial Orientation
Environmental Science & Technology Letters ( IF 10.9 ) Pub Date : 2017-12-15 00:00:00 , DOI: 10.1021/acs.estlett.7b00509
Jinkai Xue 1 , Sara BinAhmed 1 , Zhaoxing Wang 1 , Nathan G. Karp 1 , Benjamin L. Stottrup 2 , Santiago Romero-Vargas Castrillón 1
Affiliation  

The potential of graphene oxide (GO) in environmental applications, such as the development of antimicrobial materials and low-fouling membranes, has thus far been hindered by an incomplete understanding of bioadhesion mechanisms on GO interfaces. Using atomic force microscopy (AFM)-based single-cell force spectroscopy, we investigate the adhesion of single Pseudomonas fluorescens cells on GO-functionalized interfaces possessing distinct morphologies. Specifically, we investigate Si-GO surfaces, in which Langmuir–Blodgett GO films are transferred to Si wafers by dip-coating, forming an immobilized layer of horizontally arranged GO nanosheets, and PLL-GO surfaces, where GO nanosheets, edge-tethered to poly-l-lysine, form an interface characterized by morphological and conformational disorder. We observe strong adhesion forces on both Si-GO and PLL-GO surfaces; analysis of the pull-off forces in terms of the worm-like chain model reveals that adhesion is driven by hydrophobic interactions between proteinaceous adhesins on P. fluorescens and graphenic basal planes. We further show that adhesion forces are significantly stronger on Si-GO surfaces that facilitate interactions with graphenic planes, compared to PLL-GO surfaces, which show weaker adhesion due to steric and electrostatic repulsion. These results therefore demonstrate that the spatial orientation and conformational disorder of GO nanosheets are key factors governing the interfacial properties of graphene nanomaterials.

中文翻译:

疏水性和GO工作表空间取向确定细菌对氧化石墨烯(GO)-功能化界面的粘附力。

到目前为止,由于对GO界面上生物粘附机理的不完全了解,阻碍了氧化石墨烯(GO)在环境应用中的潜力,例如抗菌材料和低污染膜的开发。使用基于原子力显微镜(AFM)的单细胞力光谱学,我们研究了荧光假单胞菌细胞在具有不同形态的GO功能化界面上的粘附。具体来说,我们研究了Si-GO表面,其中Langmuir-Blodgett GO膜通过浸涂转移到Si晶片上,形成水平排列的GO纳米片的固定层,而PLL-GO表面则将GO纳米片边缘束缚到硅片上。聚-赖氨酸,形成以形态和构象障碍为特征的界面。我们在Si-GO和PLL-GO表面上都观察到了很强的附着力。根据蠕虫样链模型对拉力的分析表明,粘附是由荧光假单胞菌和石墨烯基平面上的蛋白质粘附素之间的疏水相互作用驱动的。我们进一步表明,与PLL-GO表面相比,由于空间和静电排斥而显示出较弱的粘合性,而在促进与石墨烯平面相互作用的Si-GO表面上的粘合力明显更强。因此,这些结果表明,GO纳米片的空间取向和构象紊乱是控制石墨烯纳米材料界面特性的关键因素。
更新日期:2017-12-16
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