COLLOID–CELL INTERACTION ANALYSIS WITH ATOMIC FORCE MICROSCOPY — ζ CALCULATION AND ADHESION ANALYSIS

Abstract

The interaction between cells and colloids is an important characteristic that influences cell behavior. Theoretically, much information could be revealed by analyzing the interactions in colloid–cell contact. In this study, in order to explore the interaction between cells and colloids, we developed a novel computational method able to obtain a zeta potential directly calculated from the force distance curve and apply to adhesion analysis, which used atomic force microscope (AFM), based on DLVO (Deryaguin–Landau–Verwey–Overbeek) theory and Mann Whitney U test, and combined with Zetasizer measurement. The calculation and analysis of [Formula: see text] of the cell surfaces of ncyc-1324 yeast, ncyc-1681 yeast and Pseudomonas fluorescens showed that pH affected the electrostatic distribution on the cell surface. Compared with the previous research methods, this method significantly reduces the computation and manual control, which is an effective method for multi-element surface analysis and comparison. For example, the reverse calculation and curve fitting method will significantly request more computation and manual control to set up the reference force curve that simulated with set zeta potential, while this method only need to calculate on one force curve. The deconvolution of different adhesion events from force curves showed that the heterogeneity of cell surface can be significantly displayed. This provides a method for determining the complexity of the cell surface. Furthermore, this method was used to study the effect of amoxicillin on cell surface interaction, which showed that the cells surface forces were influenced even the medicine concentration is not enough to make significant influence on microbials optical observation appearance. Thus, AFM force analysis is a more sensitive method to research the medicine influence compared to the traditional method.