High sensitivity detection of protein molecules picked up on a probe of atomic force microscope based on the fluorescence detection by a total internal reflection fluorescence microscope

We developed a method to detect and identify proteins on a probe of the atomic force microscope (AFM) with a high sensitivity. Due to a low background noise of the total internal reflection fluorescence microscope employed as a detecting system, we were able to achieve a high enough sensitivity to detect zeptomole orders of protein molecules immobilized on the tip. Several different methods to immobilize protein molecules to AFM-probes were tested, meant for a wide range of applications of this method. Furthermore, we demonstrated that different proteins were clearly distinguished by immunofluorescence microscopy on the probe using their specific antibodies. (C) 2004 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.