Surface Coatings Modulate the Differences in the Adhesion Forces of Eukaryotic and Prokaryotic Cells as Detected by Single Cell Force Microscopy

Abstract

Single cell force microscopy was used to investigate the maximum detachment force (MDF) of primary neuronal mouse cells (PNCs), osteoblastic cells (MC3T3), and prokaryotic cells (Staphylococcus capitis subsp. capitis) from different surfaces after contact times of 1 to 5 seconds. Positively charged silicon nitride surfaces were coated with positively charged polyethyleneimine (PEI) or poly-D-lysine. Laminin was used as the second coating. PEI induced MDFs of the order of 5 to 20 nN, slightly higher than silicon nitride did. Lower MDFs (1 to 5 nN) were detected on PEI/laminin with the lowest on PDL/laminin. To abstract from the individual cell properties, such as size, and to obtain cell type-specific MDFs, the MDFs of each cell on the different coatings were normalized to the silicon nitride reference for the longest contact time. The differences in MDF between prokaryotic and eukaryotic cells were generally of similar dimensions, except on PDL/laminin, which discriminated against the prokaryotic cells. We explain the lower MDFs on laminin by the spatial prevention of the electrostatic cell adhesion to the underlying polymers. However, PEI can form long flexible loops protruding from the surface-bound layer that may span the laminin layer and easily bind to cellular surfaces and the small prokaryotic cells. This was reflected in increased MDFs after two-second contact times on silicon nitride, whereas the two-second values were already observed after one second on PEI or PEI/laminin. We assume that the electrostatic charge interaction with the PEI loops is more important for the initial adhesion of the smaller prokaryotic cells than for eukaryotic cells.

From plants to antimicrobials: Natural products against bacterial membranes

“…It has been used to assume bacteria and other procaryotes as "bags of enzymes" with no specific cellular architecture (Wysotzki & Gimsa, 2019). After the invention of the electron microscope, a great opportunity was provided for scientists to study and identify microbial organelles that helped to confirm the lack of a defined nucleus.…”

“…It seems to be no physical barrier to release these vesicles into the extracellular environment, but, on the other hand, due to the presence of thick walls in Gram-positive bacteria, fungi, and Mycobacterium, little research has been done on the extracellular vesicles (Beveridge, 1980;Nowotarska, Nowotarski, Friedman, & Situ, 2014). Bacterial membrane is also the site of electron transferring chain and production of ATP or the site of cell proliferation and division (Bentley & Parkhill, 2004;Wysotzki & Gimsa, 2019). Therefore, investigating the mechanism of cell membrane destruction as well as factors affecting this barrier is particularly important.…”