Authors: W.T. Johnson
Affilation: Agilent Technologies, United States
Pages: 278 - 281
Keywords: AFM, ligand-receptor, molecular recognition, PEG, nanoscale chemistry
Biomolecular interactions, which are responsible for many physiologically important processes, can be studied by molecular recognition force microscopy (MRFM). In MRFM, nanoNewton scale single molecule interactions are observed and quantified one by one as an AFM probe that has been modified with a ligand or an antibody approaches and then is subsequently withdrawn away from a surface that contains binding sites. Topography and recognition (TREC) imaging also relies on AFM probes that have been modified with biomolecular entities. These modified AFM probes are oscillated and scanned over a sample in order to generate a topography image of the sample and a high resolution map of the biomolecular interactions. TREC imaging allows specific types of molecules to be identified in compositionally complex samples with nanometer-scale lateral resolution. It has been used to locate and plot areas of recognition between nucleic acids and proteins, antibodies and antigens and smaller ligands and their receptors. In both MRFM and TREC, nucleic acids, antibodies or smaller ligands are attached to a flexible PEG (polyethylene glycol) tethers that are in turn attached to the tip of the AFM probe. Compared to ligands attached directly to AFM probes, these flexible PEG tethers offer many advantages.