What nanotechnology could do for DNA
DNA threading through pore with trapped gold nanoparticle
Oeiras, 07.04.09
The idea of sequencing DNA by making a strand go through a pore and then determine the nucleotides as they emerge is not new. But so far DNA molecules went through α-hemolysin – a bacterial protein pore widely used in single molecule approaches – too fast to make sequencing reliable. By combining α-hemolysin and gold nanoparticles, Astier and collaborators provide a nanotool for slowing the DNA threading. The results, obtained at ITQB under the framework of the MIT-Portugal Program, are now published in Small.
The researchers demonstrated that coated gold nanoparticles can be trapped inside the nanopore making single stranded DNA molecules pass though the pore 100 times slower. The experimental system is made of two aqueous chambers separated by a lipidic membrane with a single α-hemolysin; applying a fixed potential produces a certain current, which is partially or totally blocked if the pore is obstructed. By measuring the current intensity and the duration of the block, it is possible to determine what is happening inside the pore.
But the advantages of this golden nanotool do not end in DNA. A gold nanoparticle can be functionalized, that is to say it can have different coats for different purposes, conferring selectivity to the nanopore it is trapped to. Possible applications include detection tools for different metabolites or single molecule catalysis.
UPDATE 23/04/09
Brown University Scientists Explore Magnetic Tweezers for Controlling DNA's Speed Through Nanopore
By Julia Karow
In Sequence, April 21, 2009
Electrophysiological Study of Single Gold Nanoparticle/α-Hemolysin Complex Formation: A Nanotool to Slow Down ssDNA Through the a-Hemolysin Nanopore
Yann Astier, Oktay Uzun, and Francesco Stellacci
Yann Astier, Assistant Researcher, is head of the Single Molecule Processes Laboratory at ITQB; Oktay Uzun and Francesco Stellacci work at the Massachusetts Institute of Technology.
Small (Wiley Interscience journal) provides a forum for experimental and theoretical studies of fundamental and applied interdisciplinary research at the nano- and microscale. With its Impact Factor (2007) of 6.408 Small is ranked #3 in the category Nanoscience & Nanotechnology and among the Top 10 multidisciplinary journals, covering a broad spectrum of topics at the nano- and microscale at the interface of materials science, chemistry, physics, engineering, medicine, and biology.
