Adhesive force between graphene nanoscale flakes and living biological cells

作者：Al Faouri Radwan^*; Henry Ralph; Biris Alexandru S; Sleezer Rob; Salamo Gregory J

来源：Journal of Applied Toxicology, 2017, 37(11): 1346-1353.

DOI：10.1002/jat.3478

• graphene
• adhesion
• E. coli
• atomic force microscopy
• transmission electron microscopy

We report on a measurement technique that quantifies the adhesive force between multi-layers of graphene flakes and the cell wall of live Escherichia coli cells using atomic force microscopy (AFM) in-fluid Peak Force- Quantitative Nanomechanical Mapping mode. To measure the adhesive force, we made use of the negative charge of E. coli cells to allow them to stick to positively charged surfaces, such as glass or silicon, that were covered by poly-L-Lysine. With this approach, cells were held in place for AFM characterization. Both pristine graphene (PG) flakes and functionalized graphene (FG) flakes were put on the E. coli cells and measurements of lateral size, flake thickness, and adhesion were made. Using this approach, the measured values of the adhesive force between multi-layers of graphene flakes (total thickness of 50nm) and E. coli was determined to be equal or greater than 43165pN for (PG) and 694 +/- 98pN for the (FG). More interestingly, the adhesive force of a graphene flake (thickness 1.3nm) with the cell is determined to be equal or greater than 38.2 +/- 16.4pNforthe(PG) and 34.8 +/- 15.3pNforthe(FG). These interaction values can play an important role in determining and understanding the possible toxicity of graphene flakes.

• 出版日期2017-11