Cell Micropipette Aspiration in Abaqus 1

[CellBME3]

I'm currently working on finite element modeling of cell micropipette aspiration using abaqus. I am relatively new to the program and was wondering if anyone might be able to offer some insight on a few of my issues. In applying a negative pressure (pipette pressure)to my cell which is modeled as a 2D homogeneous sphere, I am having an issue getting the bottom of my cell to move vertically so that the cell radius decreases appropriately as the cell is aspirated into the pipette. My other issue thus far is that in defining my interaction between the pipette corner and the cell surface, the point where the initial contact is made is not aspirated into the cell. Is there a way I can define this interaction so the point of initial contact will move into the pipette instead of remaining fixed at the original location? Any help would be greatly appreciated. I have attached a few screen shots to give you an idea of what I have so far.

Thanks

http://files.engineering.com/getfil...-8c77-9ec27dde6495&file=Abaqus_Undeformed.JPG

http://files.engineering.com/getfil...417536f81e&file=Abaqus_Deformed_Pressure5.JPG

http://files.engineering.com/getfil...5bef9&file=Abaqus_Deformed_Pressure5_zoom.JPG