[New measurement technics in biology and medicine: atomic force microscopy (part II)].

At present, there are a lot of biological and medical research fields, where atomic force microscopy (AFM) is being successfully used. AFM has contributed to research in the investigation of DNA, RNA structure, nucleic acid--protein complexes, chromosomes, ligand-receptor binding, cell membranes, proteins, lipids, carbohydrates, living cells (yeasts, bacteria, neurons, erythrocytes, endothelial cells); it enables to monitor drug interactions with cells and tissues, to visualize changes in protein molecular structure and crystal growth. Unlike electron microscopes, samples do not need to be stained, coated or frozen. Recent work indicates that, in the near future, AFM may be employed in ultra-sensitive immunoassay detection without any kind of labeling for both qualitative and quantitative work. AFM is more than a surface--imaging tool in that force measurements can be used to probe the physical properties of the specimen, such as molecular interactions, surface hydrophobicity, surface charges, and mechanical properties.