Seen any good atoms lately? That's what University of Utah scientists are looking at under their newest microscopes.
The U.'s new atomic force microscopes will allow scientists to study interactions of proteins with DNA molecules and the interactions of enzymes with substrates."Atomic force microscopy is an entirely new method of providing images of submicroscopic features on the surfaces of materials," said Joseph D. Andrade, chairman of the department of bioengineering.
The newest microscopes combine the principles of a scanning tunneling microscope and a stylus profiolometer.
With the capability to study single atoms and rearrange them individually, scientists hope to create a new generation of "designer materials." The result of this process of nanoengineering could be an entirely new process for manufacturing products.
Andrade's group also expects to use the new microscope to observe the surface structure of the complex biomedical polymers known as polyurethanes, which are widely used in artificial hearts, heart-assist devices and other medical products.
Studying proteins at surfaces is important in the development of materials and devices used to measure chemical concentrations for medical diagnoses. A key to expanding knowledge about proteins is the mapping of the human genome, the complete set of an individual's genes. The genome could number as many as 10 million genes made up on DNA molecules.
The microscope probes the electron atmosphere of a surface, measuring the tiny forces that exist between atoms. The instrument charts the distance to the surface in terms of how strongly the atoms repel or attract each other.
To obtain an atomic-scale image, a material specimen is mounted onto a piezoelectric crystal and scanned beneath a sharp diamond tip attached to a cantilever, a beam supported only at one end. The diamond-tipped stylus moves across the surface, and the forces between the material's surface and the tip deflect the cantilever. The scope monitors the deflection in response to forces exerted on the cantilever.
The tip traces the shape of the surface, similar to the way a phonographic needle traces the surface of a record. The measurements are later assembled into a computerized picture of the surface.