In this paper, a new approach is demonstrated to measure the compression elasticity of single biomolecule in small force regime (<0.5 nN) using vibrating mode scanning polarization force microscopy (VSPFM). With th...In this paper, a new approach is demonstrated to measure the compression elasticity of single biomolecule in small force regime (<0.5 nN) using vibrating mode scanning polarization force microscopy (VSPFM). With this method we investigate the compression elasticity of a single DNA molecule in the radial direction (perpendicular to DNA strands). The radial deformation of DNA molecules deposited on mica surface is shown to be able to reach about 50% un der external load, and this remarkable deformation is re- versible. In addition, the compression spring constant of DNA molecules is estimated to be about 0.6 nN/nm according to the height-force curves.展开更多
Atomic force micriscope (AFM)-based dip-pen nanolithography (DPN) is an emerging approach for con-structing nanostructures on material surfaces such as gold, silicon and silicon oxide. Although DPN is a powerful tech-...Atomic force micriscope (AFM)-based dip-pen nanolithography (DPN) is an emerging approach for con-structing nanostructures on material surfaces such as gold, silicon and silicon oxide. Although DPN is a powerful tech-nique, it has not shown its ability of direct-writing and pat-terning of nanostructures on surfaces of soft materials, for example biomacromolecules. Direct depositing on soft sur-faces becomes possible with the introduction of a com-bined-dynamic mode DPN rather than mostly used contact mode DPN or tapping mode DPN. In this report, the com-bined dynamic mode DPN is used for direct depositing pro-tein ink on DNA molecules at the nanometer scale.展开更多
The height of double-stranded DNA (dsDNA) is measured by lift mode AFM combined with conventional tapping mode AFM. While the tip scan height is raised step by step, the tip pressure on sample is decreased gradually. ...The height of double-stranded DNA (dsDNA) is measured by lift mode AFM combined with conventional tapping mode AFM. While the tip scan height is raised step by step, the tip pressure on sample is decreased gradually. As a result, the deformation of the DNA strands decreases, and the height of double-stranded DNA (dsDNA) molecule can be deduced by the tip lift height. The measured height of dsDNA is 1.5±0.2 nm in lift mode, but only 0.8±0.2 nm in conventional tapping mode. This demonstrates that the tip pressure is a key factor in soft sample height measurement resulting in artificating lower values via conventional tap- ping mode.展开更多
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.10304011 and 10335070)Chinese Academy of Sciences+1 种基金Shanghai Science Committee Ningbo University.
文摘In this paper, a new approach is demonstrated to measure the compression elasticity of single biomolecule in small force regime (<0.5 nN) using vibrating mode scanning polarization force microscopy (VSPFM). With this method we investigate the compression elasticity of a single DNA molecule in the radial direction (perpendicular to DNA strands). The radial deformation of DNA molecules deposited on mica surface is shown to be able to reach about 50% un der external load, and this remarkable deformation is re- versible. In addition, the compression spring constant of DNA molecules is estimated to be about 0.6 nN/nm according to the height-force curves.
文摘Atomic force micriscope (AFM)-based dip-pen nanolithography (DPN) is an emerging approach for con-structing nanostructures on material surfaces such as gold, silicon and silicon oxide. Although DPN is a powerful tech-nique, it has not shown its ability of direct-writing and pat-terning of nanostructures on surfaces of soft materials, for example biomacromolecules. Direct depositing on soft sur-faces becomes possible with the introduction of a com-bined-dynamic mode DPN rather than mostly used contact mode DPN or tapping mode DPN. In this report, the com-bined dynamic mode DPN is used for direct depositing pro-tein ink on DNA molecules at the nanometer scale.
文摘The height of double-stranded DNA (dsDNA) is measured by lift mode AFM combined with conventional tapping mode AFM. While the tip scan height is raised step by step, the tip pressure on sample is decreased gradually. As a result, the deformation of the DNA strands decreases, and the height of double-stranded DNA (dsDNA) molecule can be deduced by the tip lift height. The measured height of dsDNA is 1.5±0.2 nm in lift mode, but only 0.8±0.2 nm in conventional tapping mode. This demonstrates that the tip pressure is a key factor in soft sample height measurement resulting in artificating lower values via conventional tap- ping mode.
