Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Focusing light on the nanoscale: Making nanolenses from metallic particles and DNA

26.10.2012
Conventional lenses can only focus light to a volume on the femtoliter (10-15) range or in other words to dimensions of 1 µm3.

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.
TU Braunschweig

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:
“Fluorescence Enhancement at Docking Sites of DNA-Directed Self-Assembled Nanoantennas”. Guillermo Acuna, Friederike Möller, Phil Holzmeister, Susanne Beater, Birka Lalkens and Philip Tinnefeld. SCIENCE, Friday, 26 October 2012, DOI 10.1126/science.1228638
Contact:
Prof. Dr. Philip Tinnefeld.
Institut für Physikalische und Theoretische Chemie
Technische Universität Braunschweig
Hans-Sommer-Strasse 10
38106 Braunschweig
p.tinnefeld@tu-braunschweig.de
Tel.: +49 531 391 5330
Dr. Guillermo Acuna
Institut für Physikalische und Theoretische Chemie
Technische Universität Braunschweig
Hans-Sommer-Strasse 10
38106 Braunschweig
g.acuna@tu-braunschweig.de
Tel.: +49 531 391 7377

Ulrike Rolf | idw
Further information:
http://www.tu-braunschweig.de

More articles from Interdisciplinary Research:

nachricht New dental implant with built-in reservoir reduces risk of infections
18.01.2017 | KU Leuven

nachricht Many muons: Imaging the underground with help from the cosmos
19.12.2016 | DOE/Pacific Northwest National Laboratory

All articles from Interdisciplinary Research >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>