June 25th AM

Today, we measure the adhesion properties of fibrinogen in order to study its effects on thrombus formation. A HEK293 cell(human embryonic kidney) was placed under the cantilever end. The HEK cell was placed on the cantilever end instead of a tip. The cell contains integrin proteins on its membrane which causes the cell to adhere to surfaces. The glass-slide was incubated with a thin layer of fibrinogen molecules. The cantilever was lowered onto the surface until the cell touches the surface. Adhesion of the cell to the fibrinogen surface occurs. Next, the cantilever was slowly pulled from the surface with a very small pN force. A graph of the applied force versus time was plotted on the computer to indicate the force necessary to pull the cell away from the fibrinogen surface. In previous experiments, different surfaces were used and a small microliter drop of cells were incubated with the surface. Excess cells were rinsed off to see how many cells adhere to the different surfaces. In this experiment the actual force needed to pull apart the cell from the surface was measured.