Tag Archives: PointProbe® Plus

5′-(CGA)n sequence-assisted pH-controlled assembly of supramolecular DNA nanostructure

In the research article “5′-(CGA)n sequence-assisted pH-controlled assembly of supramolecular DNA nanostructure” Yuting Yan, Yanwei Cao, Chunsheng Xiao, Yang Li, Xiaoxuan Xiang and Xinhua Guo demonstratethat the connection of duplex-forming sequences with a G-quadruplex-forming sequence (G6) could be used to construct DNA supramolecular nanostructures with alternating B-duplex and G-quadruplex structures. Their results demonstrate that the TT linker between B-duplex and G-quadruplex structures are necessary for the construction of such nanostructures, because the TT linker can provide structural flexibility for the bending of duplexes at the terminal of G-quadruplex.*

The formation of DNA supramolecular nanostructures was directly observed through AFM measurements.  Atomic force microscopy (AFM) was performed using NANOSENSORS™ PointProbe® Plus PPP-NCHR tapping mode AFM probes.

Figure 5. from “5′-(CGA)n sequence-assisted pH-controlled assembly of supramolecular DNA nanostructure” by Yuting Yan et al.: AFM images of the nanostructures formed by DNA G-quadruplexes self-assembly in KOAc buffer solution; (a,b) SG2 at pH 9.0, (c,d) SG2 at pH 4.5, (e,f) a mixture of SG2 and CSG2 at pH 4.5, (g,h) a mixture of SG2 and CSG2 at pH 9.0. The length of side is 2 µm and the scale bar is 500 nm. NANOSENSORS™ PointProbe® Plus PPP-NCHR AFM probes were used for all AFM images.
Figure 5. from “5′-(CGA)n sequence-assisted pH-controlled assembly of supramolecular DNA nanostructure” by Yuting Yan et al.: AFM images of the nanostructures formed by DNA G-quadruplexes self-assembly in KOAc buffer solution; (a,b) SG2 at pH 9.0, (c,d) SG2 at pH 4.5, (e,f) a mixture of SG2 and CSG2 at pH 4.5, (g,h) a mixture of SG2 and CSG2 at pH 9.0. The length of side is 2 µm and the scale bar is 500 nm.

AFM microscopy was performed on the fresh mica surfaces with the help of magnesium ions which can bind negatively charged DNA strands. The DNA samples were annealed at 100 µM in 100 mM K+ solution at 4°C for one week. Then aliquots were diluted with 2 mM MgCl2 aqueous solution to give a 20 µl analyte containing 1.5 µM DNA. The analytes were spread evenly on the mica surface for 5–8 min. Subsequently, the mica surface was washed with Milli-Q water to wipe off the excess salt, and finally dried in the air.*

*Yuting Yan, Yanwei Cao, Chunsheng Xiao, Yang Li, Xiaoxuan Xiang, Xinhua Guo
5′-(CGA)n sequence-assisted pH-controlled assembly of supramolecular DNA nanostructure
Royal Society Open Science, 1 August 2018, Volume 5, Issue 8
DOI: https://doi.org/10.1098/rsos.180123

Open Access: The article “5′-(CGA)n sequence-assisted pH-controlled assembly of supramolecular DNA nanostructure” by  Yuting Yan et al. is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

Happy Swiss National Holiday with Smallest Swiss Cross

Basel University : Smallest Swiss Cross – Made of 20 Single Atoms ( a NANOSENSORS PPP-NCL was used for this image)

20 bromine atoms positioned on a sodium chloride surface using the tip of an atomic force microscope at room temperature, creating a Swiss cross with the size of 5.6nm. The structure is stable at room temperature and was achieved by exchanging chlorine with bromine atoms. (Fig: University of Basel, Department of Physics), image made with NANOSENSORS PPP-NCL AFM tip
20 bromine atoms positioned on a sodium chloride surface using the tip of an atomic force microscope at room temperature, creating a Swiss cross with the size of 5.6nm. The structure is stable at room temperature and was achieved by exchanging chlorine with bromine atoms. (Fig: University of Basel, Department of Physics)

 

Consistent AFM tip shape leading to reproducible results – NANOSENSORS PointProbe Plus Screencast passes 500 views mark

The screencast held by Head of R&D Thomas Sulzbach  on the  NANOSENSORS PointProbe® Plus Silicon AFM probe series  with a consistent tip shape leading to more reproducible results has just passed the 500 views mark.
Congratulations Thomas!

Screencasts on the PointProbe® Plus are also available in Japanese

and in Chinese:

also on youku http://v.youku.com/v_show/id_XNzMyMDg2MjQ4.html