Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


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

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.

“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
Prof. Dr. Philip Tinnefeld.
Institut für Physikalische und Theoretische Chemie
Technische Universität Braunschweig
Hans-Sommer-Strasse 10
38106 Braunschweig
Tel.: +49 531 391 5330
Dr. Guillermo Acuna
Institut für Physikalische und Theoretische Chemie
Technische Universität Braunschweig
Hans-Sommer-Strasse 10
38106 Braunschweig
Tel.: +49 531 391 7377

Ulrike Rolf | idw
Further information:

More articles from Interdisciplinary Research:

nachricht Lego-like wall produces acoustic holograms
17.10.2016 | Duke University

nachricht New evidence on terrestrial and oceanic responses to climate change over last millennium
11.10.2016 | University of Granada

All articles from Interdisciplinary Research >>>

The most recent press releases about innovation >>>

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

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>