Researchers in China are reporting development of a new DNA "tweezers"
that are the first of their kind capable of grasping and releasing objects on-demand.
The microscopic tweezers could have several potential uses, the researchers
note. Those include microsurgery, drug and gene delivery for gene therapy, and
in the manufacturing of nano-sized circuits for futuristic electronics. Their
study is scheduled for the November 12 issue of the weekly Journal
of the American Chemical Society.
 | | A pair of DNA tweezers are constructed, which are capable of capturing, holding and releasing a DNA object by playing with the open and close actions of the tweezers assisted by pH switchings. The object is captured between the tweezers’ arms at pH 5.0 through Hoogsteen hydrogen bonding and can be stably held even when the pH is increased to 5.7 after the tweezers are closed. Upon introducing a DNA unlocker strand, the tweezers are opened and the object gets released. This capture-hold-release process can be easily cycled without losing much of its efficiency. |
Zhaoxiang Deng and colleagues note that other scientists have developed tweezers
made of DNA, the double helix molecule and chemical blueprint of life. Those
tweezers can open and close by responding to complementary chemical components
found in DNA’s backbone. However, getting the tweezers to grasp and release
objects like real tweezers has remained a bioengineering challenge until now.
The scientists describe development of a pair of DNA tweezers composed of four
DNA strands — three which act as the “arms.” In laboratory
studies, the scientists showed that they could grab a piece of target DNA in
the arms of the tweezers and release it on-demand using a controlled series
of hydrogen bonding and pH changes. The scientists used fluorescent gel imaging
to confirm the effectiveness of the tweezers’ operation. — MTS
Posted October 30th, 2008
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