Metal nanoparticles have radically different electronic, optical and magnetic properties from their larger states, which makes them useful as materials in new, ultra-small devices such as biological sensors. Constructing such devices, however, is difficult because, unlike atoms, nanoparticles lack directional bonds that allow them to be arranged precisely.
One strategy to overcome this limitation is to attach oligonucleotides—single strands of molecules that constitute DNA—to nanoparticle surfaces, and then, through Watson–Crick base pairing of the nucleic acids, join the nanoparticles together. However, manipulating the number and positions of oligonucleotides on the nanoparticles has been impossible.
Now, Kenji Suzuki, Kazuo Hosokawa and Mizuo Maeda from the RIKEN Advanced Science Institute in Wako have developed a method to immobilize oligonucleotides on gold nanoparticle surfaces with precise control over their number and geometric arrangement 1. Because this procedure can be used for nanoparticles other than gold, it should initiate improved techniques for spontaneous assembly of small materials into complex structures—so-called ‘bottom–up’ nanotechnologies.
In their proof-of-principle experiment, Suzuki and colleagues combined two oligonucleotides containing reactive thiol (sulfur-hydrogen) groups with a third, non-thiolated oligonucleotide template to create a DNA nanostructure. This DNA template was then reacted with a gold nanoparticle, forming a complex through the active thiol groups. Finally, the DNA template was separated from the complex, leaving two free oligonucleotide strands on the gold nanoparticle.
Transmission electron microscopy imaging confirmed the success of the DNA template technique. Without the template, the nucleic acids were observed at random locations on the nanoparticles. With the template, the two oligonucleotides were always seen at distinct geometric positions as arrangements controlled by the specific DNA nanostructure.
Suzuki says that top-down methods such as immobilization by a tip of scanning probe microscope are very precise, but prohibitively slow. In contrast, his team’s DNA template is extremely fast and automated, and represents a new type of ‘nanomachine.’
“Each nanomachine catches a certain number of oligonucleotides, immobilizes them onto a nanoparticle, and then releases them,” explains Suzuki. “Naturally, this task is best suited to a DNA template having complementary sequences to the oligonucleotides, since duplex formation is then completely reversible.”
According to Suzuki, creating nanoparticles with atom-like binding capabilities would have advantages beyond developing new types of nanostructures. “I knew that such a result would be welcomed by many other researchers and would accelerate the whole field,” he says.
1. Suzuki, K., Hosokawa, K. & Maeda, M. Controlling the number and positions of oligonucleotides on gold nanoparticle surfaces. Journal of the American Chemical Society 131, 7518–7519 (2009). |article|The corresponding author for this highlight is based at the RIKEN Bioengineering Laboratory
Saeko Okada | Research asia research news
Cancer diagnosis: no more needles?
25.05.2018 | Christian-Albrechts-Universität zu Kiel
Less is more? Gene switch for healthy aging found
25.05.2018 | Leibniz-Institut für Alternsforschung - Fritz-Lipmann-Institut e.V. (FLI)
The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.
Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...
A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.
The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
25.05.2018 | Event News
02.05.2018 | Event News
13.04.2018 | Event News
25.05.2018 | Event News
25.05.2018 | Machine Engineering
25.05.2018 | Life Sciences