This constrain arises from an effect called diffraction, inherent to all conventional lenses, and represents an obstacle for the development of nanotechnology applications.
The sketch shows the DNA origami nanopillar (in gray) immobilized on a coverslip. Two gold nanoparticles of 80-100 nm diameter serve as nanoantenna and focus the light in the hotspot between the nanoparticles. A fluorescence dye as active optical source attached in the hotspots reports on the fluorescence enhancement.
The interdisciplinary group of scientists of Prof. Dr. Philip Tinnefeld have overcome this problem by an elegant self-assembly technique that produces millions of nanolenses on the basis of metallic nanoparticles in combination with DNA structures. These nanolenses enable ~100fold more sensitive detection of even single molecules than previous approaches.
The original publication is presented in the current issue of the scientific journal “SCIENCE”.
In the emerging field of nanophotonics scientist study the behavior of light at subwavelength dimensions. It is known, for example, that a pair of gold nanoparticles can focus light to a spot ~1000fold smaller than conventional lenses. Such tight focusing has great technological potential, e.g. for nanoscale signal processing in optical computers, for ultra-sensitive detection in diagnostics as well as for biotechnological applications such as DNA sequencing. It has, however, been a challenge to place gold nanoparticles of 80-100 nm dimensions at a defined distance and to bring molecules of interest in the hotspot between the particles.
To overcome the limitations, a group of scientist led by Prof. Dr. Philip Tinnefeld at Technische Universität Braunschweig have developed nanolenses by self-assembly. Therefore, they used DNA as a construction material that was folded into the shape of a nanopillar by a technique called DNA origami (see sketch). This DNA nanopillar served as a scaffold to which the nanoparticles were attached. The DNA origami was further modified to attach functionality. Specific molecules at the bottom of the nanopillar allowed placing it upright on a cover slip. Further attachment sites between the nanoparticles were used to attach optical sources such as a fluorescent dye. Biocompatibility of the nanooptical devices was proven by the single-molecule detection of short nucleic acid diffusing in the solution. The functioning of the self-assembled nanolens was demonstrated by a drastic fluorescence enhancement by a factor of ~100 for single fluorescent molecules.
The scientists are confident that their technique might have an impact on a broad range of research disciplines. Prof. Dr. Philip Tinnefeld describes the extent of the possible applications enabled by their findings: “Concentrating the light into very reduced volume in the zeptoliter range allows us to perform studies on individual objects with better signals and at higher concentrations where biologically relevant processes like DNA replication occur. Additionally, we can now investigate how light interacts with nanoparticles, a key component for the field of nanophotonics”.
This work was funded by the European Research Council (ERC), the Volkswagen Foundation and the Center for NanoScience CeNS.Publication:
Ulrike Rolf | idw
Decoding the regulation of cell survival - A major step towards preventing neurons from dying
04.10.2018 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden
New Cluster of Excellence “Centre for Tactile Internet with Human-in-the-Loop” (CeTI)
28.09.2018 | Technische Universität Dresden
Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.
Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...
Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.
When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure
Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...
09.11.2018 | Event News
06.11.2018 | Event News
23.10.2018 | Event News
16.11.2018 | Health and Medicine
16.11.2018 | Life Sciences
16.11.2018 | Life Sciences