By a News Reporter-Staff News Editor at Life Science Weekly -- Investigators discuss new findings in DNA Research. According to news reporting originating in Lausanne, Switzerland, by NewsRx journalists, research stated, "Few examples of sub nanometer resolution on biomolecules can be found in literature. In particular, AFM experiments on DNA mostly fail to show the double helical groove periodicity, and so far such a feat was only achieved in liquid."
The news reporters obtained a quote from the research from the Swiss Federal Institute of Technology, "Here we describe a method that produces highly resolved images of DNA where contrast can be assigned to submolecular features such as DNA helix's grooves. Two types of AFM experiments are presented: (1) We started by imaging DNA with Frequency Modulation (FM) AFM, where a shift in resonance frequency is used as a feedback signal and maintained constant during imaging. With FM-AFM we performed experiments in the non-contact (NC) mode, with z-feedback on, where only gentle (few tens of pN) non compressive force is applied between the tip and the sample. (2) Then we switched off the z-feedback and scanned the DNA sample at constant height measuring frequency modulation in order to acquire frequency shift maps of the sample. This was done at several separations including the distances where the frequency feedback is not stable due to the non-monotonicity of the frequency shift curve. At this distance sub-molecular resolution was reached and a calculation of the tip-sample van der Wools interaction at constant height, as well as the periodicity of the observed features that ranges from 3 to 5 nm, suggest that these correspond to the DNA helix grooves. This is the first experimental study where submolecular features of single DNA molecules are observed in dry environment."
According to the news reporters, the research concluded: "The knowledge of DNA structure when dried and deposited on flat substrates is important for proper understanding of DNA's electronic behavior and its eventual nanotechnology applications."
For more information on this research see: Fine DNA structure revealed by constant height frequency modulation AFM imaging. European Polymer Journal, 2013;49(8):1916-1922. European Polymer Journal can be contacted at: Pergamon-Elsevier Science Ltd, The Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB, England. (Elsevier - www.elsevier.com; European Polymer Journal - www.elsevier.com/wps/product/cws_home/294)
Our news correspondents report that additional information may be obtained by contacting A. Cerreta, Ecole Polytechnic Fed Lausanne, Lab Phys Living Matter, CH-1015 Lausanne, Switzerland. Additional authors for this research include D. Vobornik and G. Dietler (see also DNA Research).
Keywords for this news article include: Europe, Lausanne, Switzerland, DNA Research
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