Site localization of membrane-bound proteins on whole cell level using atomic force microscopy

This study presents molecular recognition method, which is based on specific force measurements between modified AFM (atomic force microscopy) tip and mammalian cell. The presented method allows recognition of specific cell surface proteins and receptor sites by nanometer accuracy level. Here we demonstrate specific recognition of membrane-bound Osteopontin (OPN) sites on preosteogenic cell membrane. By merging specific force detection map of the proteins and topography image of the cell, we create a new image (recognition image), which demonstrates the exact locations of the proteins relative to the cell membrane. The recognition results indicate the strong affinity between the modified tip and the target molecules, therefore, it enables the use of an AFM as a remarkable nanoscale tracking tool on the whole cell level.