Scanning tunnelling microscopy of biomacromolecules

Abstract
When imaging biomacromolecules with a STM, coating of specimens with a conductive layer is a convenient preparation method which provides a good rate of success. Utilizing evaporated platinum/carbon as a coating film we have investigated two biomacromolecules of very different appearance. The first of these is the HPI‐layer, a natural two‐dimensional protein crystal with a period of 18 nm, which is found on the surface of the bacterium Deinococcus radiodurans. The second specimen is type IV collagen which forms long triple‐helical strands approx. 1·5nm in diameter. The resulting STM pictures compare very well with electron microscopical images.