Chapter 16 - Structure, behavior, and manipulation of nanoscale biological assemblies

Abstract

This chapter focuses on three different aspects of biologically derived nanostructured materials. One of the aspects—use of scanning probe microscopy (SPM) in studying biological assemblies that specifically support biological membranes, nucleic acids, and nucleoprotein complexes. Second, the use of more general protein phospholipid assemblies as nanostructured materials for the study of protein function at interfaces and the development of operational molecular devices. Another aspect is the use of general surface immobilization techniques to engineer nanostructured materials from functional proteins. SPM combines independent mobility in all three spatial directions (scanning) with a detection system capable of detecting some characteristic of the surface (probing). The scanning tunneling microscopy (STM) scans a surface with a conductive tip made of a metal wire etched to a fine point, and the microscopes' electronics detects the tunneling current passing between the tip and the surface, typically from a distance of about 10 Å. Scanning force microscope (SFM) can provide atomic resolution on hard surfaces like mineral crystals. Achieving such a high resolution requires an exceptionally sharp tip, and the scan must be conducted at a relatively high force level, in the tens of nanonewtons range. The resolution attainable on biomolecules is lower because they are often deformed or damaged at such high tip forces and because it is generally difficult to bind them to a surface sufficiently rigidly to withstand high scan forces.