Thursday, November 30, 2006

American and Dutch scientists under the supervision of professor of physics Philip Nelson, University of Pennsylvania, have been studying the fragments of the DNA, and recently they discovered that molecules of this natural polymer possess the huge flexibility. The scientists used the power-atomic microscope in their studies. It allows to measure exchange forces between the atoms of special probe, so called, nanoneedle and testing sample. Nanoneedles are made from the materials close to silicon. The needle shifts according to atomic interaction and reproduces the relief of the testing sample. These microscopic movements are registered by means of a laser. It's possible to study the form of the individual molecule and even move it with the help of the nanoneedle. The authors of this reseach used this possibility. They made the needle contact fragments of the DNA, which allowed them to measure exchange forces. Derived results don't correspond with the commonly used model, which describes physical characteristics of the DNA molecule comparing it with the rigid rubber plait.