Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Nanoparticles: Making gold economical for sensing

11.10.2012
Gold nanocluster arrays developed at A*STAR are well suited for commercial applications of a high-performance sensing technique.
Cancer, food pathogens and biosecurity threats can all be detected using a sensing technique called surface enhanced Raman spectroscopy (SERS). To meet ever-increasing demands in sensitivity, however, signals from molecules of these agents require massive enhancement, and current SERS sensors require optimization. An A*STAR-led research team recently fabricated a remarkably regular array of closely packed gold nanoparticle clusters that will improve SERS sensors.

So-called ‘Raman scattering’ occurs when molecules scatter at wavelengths not present in the incident light. These molecules can be detected with SERS sensors by bringing them into contact with a nanostructured metal surface, illuminated by a laser at a particular wavelength. An ideal sensor surface should have: dense packing of metal nanostructures, commonly gold or silver, to intensify Raman scattering; a regular arrangement to produce repeatable signal levels; economical construction; and robustness to sustain sensing performance over time.

Few of the many existing approaches succeed in all categories. However, Fung Ling Yap and Sivashankar Krishnamoorthy at the A*STAR Institute of Materials Research and Engineering, Singapore, and co-workers produced closely packed nanocluster arrays of gold that incorporate the most desirable aspects for fabrication and sensing. In addition to flat surfaces, they also succeeded in coating fiber-optic tips with similarly dense nanocluster arrays (see image), which is a particularly promising development for remote-sensing applications, such as hazardous waste monitoring.

The researchers self-assembled their arrays by using surfaces coated with self-formed polymer nanoparticles, to which smaller gold nanoparticles spontaneously attached to form clusters. “It was surprising to reliably attain feature separations of less than 10 nanometers, at high yield, across macroscopic areas using simple processes such as coating and adsorption,” notes Krishnamoorthy.

By varying the size and density of the polymer features, Krishnamoorthy, Yap and co-workers tuned the cluster size and density to maximize SERS enhancements. Their technique is also efficient: less than 10 milligrams of the polymer and 100 milligrams of gold nanoparticles are needed to coat an entire 100 millimeter diameter wafer, or approximately 200 fiber tips. Both the polymer and the nanoparticles can be mass-produced at low cost. By virtue of being entirely ‘self-assembled’, the technique does not require specialized equipment or a custom-built clean room, so it is well suited to low-cost commercial implementation.

“We have filed patent applications for the work in Singapore, the USA and China,” says Krishnamoorthy. “The arrays are close to commercial exploitation as disposable sensor chips for use in portable SERS sensors, in collaboration with industry.”

The A*STAR-affiliated researchers contributing to this research are from the Institute of Materials Research and Engineering

References

Yap, F. L., Thoniyot, P., Krishnan, S. & Krishnamoorthy, S. Nanoparticle cluster arrays for high-performance SERS through directed self-assembly on flat substrates and on optical fibers. ACS Nano 6, 2056–2070 (2012).

A*STAR Research | Research asia research news
Further information:
http://www.a-star.edu.sg
http://www.researchsea.com

More articles from Materials Sciences:

nachricht A new tool for discovering nanoporous materials
23.05.2017 | Ecole Polytechnique Fédérale de Lausanne

nachricht Did you know that packaging is becoming intelligent through flash systems?
23.05.2017 | Heraeus Noblelight GmbH

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

How herpesviruses win the footrace against the immune system

26.05.2017 | Life Sciences

Water forms 'spine of hydration' around DNA, group finds

26.05.2017 | Life Sciences

First Juno science results supported by University of Leicester's Jupiter 'forecast'

26.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>