Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Microprinting Technique for Patterning Single Molecules

07.02.2007
A new process for creating patterns of individual molecules on a surface combines control of self-assembled monolayers (SAMs) and a soft lithography technique known as microcontact printing.

Scientists use the process, known as "microcontact insertion printing" to build surfaces that have molecules with specific functions inserted at known intervals on a surface. The new technique, with potential applications ranging from analysis of biochemical mixtures to molecular-scale electronic components, will be described as the cover story of the 5 February 2007 issue of the journal Applied Physics Letters by a team led by Penn State researchers Paul S. Weiss, distinguished professor of chemistry and physics; Mark Horn, associate professor of engineering science and mechanics; and Anne M. Andrews, assistant professor of veterinary and biomedical sciences.

Microcontact insertion is based on the technique of microcontact printing, in which a patterned rubber-like stamp is "inked" with a solution of molecules and then applied to a surface. However, the insertion technique does not apply molecules to the entire surface contacted, but instead fills only defects -- molecule-sized gaps -- in a layer of molecules that previously has been placed on and attached to the surface. "Lithography cannot place molecules with nanometer precision," says Weiss, "but by building the defects into the surface and then filling them selectively with this process, we can place the isolated molecules in a predesigned nano-scale or micro-scale pattern."

The process of microcontact insertion printing starts with a self-assembled monolayer (SAM) -- a chemical deposition on the surface that is one molecule thick. The researchers can build the SAM with defects, or regions in which the surface is not covered by the film. By controlling the type, size, and number of the defects, they create a pattern in which the surface appears as a matrix of exposed dots. In one example, there is an average of 10 molecules between defects, making an average separation between inserted molecules of about 5 nanometers. If defects are made larger, then more molecules are inserted in each one.

After the formation of the matrix with controlled defects, the microcontact printing technique is used to fill the exposed parts of the surface. "We use the stamp to attach molecules to the open surface," says Weiss. "Because each molecule is surrounded by the SAM, it stays in place and there is no migration." Using a series of stamps allows different molecules to be placed on the surface in a pattern, with each region of the surface holding a different type of functional molecule tethered to the surface and held in place by the surrounding inert monolayer.

The chemical functionality of the attached molecule can be made in a way that will capture specific types of molecules from a mixture. The pattern of functionalities creates a multiplexed capture surface on which chemical compounds, such as proteins, other biological molecules, or environmental contaminants can be separated from a complex mixture. Each part of the pattern can be designed for specific classes of target molecules so that a single patterned surface can be used to determine the identity and concentration of multiple components of the mixture.

In addition to its application in creation of surfaces with specific selectivity, the microcontact-insertion process could allow the controlled deposition of molecules that can interact in specific ways. This application could be used to build electronic components or other functional surfaces.

The work was a collaboration between the Weiss group, specializing in surface chemistry and self-assembly, the Andrews group, specializing in neuroscience and biosensing, and the Horn group, specializing in nanolithography. In addition to Weiss, Andrews, and Horn, the Penn State research team included postdoctoral researcher Susan D. Gillmor and graduate students Thomas J. Mullen III, Charan Srinivasan, J. Nathan Hohman, and Mitchell J. Shuster. The work was performed as a part of both the National Science Foundation funded Center for Nanoscale Science and Penn State's node of the National Nanotechnology Infrastructure Network.

Barbara K. Kennedy | EurekAlert!
Further information:
http://www.psu.edu

More articles from Physics and Astronomy:

nachricht Neutron star merger directly observed for the first time
17.10.2017 | University of Maryland

nachricht Breaking: the first light from two neutron stars merging
17.10.2017 | American Association for the Advancement of Science

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

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

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Ocean atmosphere rife with microbes

17.10.2017 | Life Sciences

Neutrons observe vitamin B6-dependent enzyme activity useful for drug development

17.10.2017 | Life Sciences

NASA finds newly formed tropical storm lan over open waters

17.10.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>