Imaging and measuring the protein distribution of lymphoma cells using atomic force microscopy

Atomic force microscopy (AFM) has proven to be a powerful tool for imaging the topographic properties of biological samples and measuring the molecular specific binding forces at cellular and molecular levels. However, there are still great difficulties in using AFM to acquire images of mammalian suspension live cells due to the suspension growth manner and the softness of the cell membrane. In this paper, lymphoma live cells were trapped in microfabricated patterned pillars and then imaged by AFM in phosphate buffered saline (PBS) solution. In addition, the CD20 distribution on the lymphoma cell surface was visualized three-dimensionally by tethering rituximabs (anti-CD20 monoclonal antibody) onto the AFM tips. The experimental results indicate that immobilization with microfabricated patterned pillars provides a novel way for anchoring suspension mammalian cells, opening the way for further investigation of the molecular mechanisms of rituximab´s anti-cancer effect.