Use of STM for analysis of surfaces of biological samples

Scanning tunnelling microscopy STM.was used to image the cell surfaces of the olfactory organ of the shark Carcharhinus longimanus and ectoderm of the frog Xenopus laeÍis blastulae of 1024 stages, as well as human low-density lipoproteins surface. The samples from two of these objects were prepared by using traditional techniques for scanning electron microscopy SEM.. The lipoprotein samples were prepared by drying in the air. A comparison of the STM images with the earlier obtained SEM images indicates that there are some earlier unknown details of the surface structures of receptor microvilli and support cell membranes of the olfactory organ of the shark. There was found a fold of membrane on the surface of the ectodermal frog embryo cells, which covered yolk granules. STM images of the lipoprotein surface were obtained without increasing conductivity treatment. q1999 Elsevier Science B.V. All rights reserved.