New microscopy laboratory to focus on nanotechnology

Trinity College Dublin's Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) opened its Advanced Microscopy Laboratory last week. The laboratory has advanced instrumentation for viewing material on the atomic scale and was funded by the Higher Education Authority and Science Foundation Ireland. It was officially opened by the Minister for Labour Affairs, and Public Service Transformation, Mr Dara Calleary, TD (pictured with CRANN researcher Dr. Despina Bazou).

The €12-million microscopy laboratory houses a helium ion microscope, a scanning electron microscopes, and a focused ion beam. The helium ion microscope allows the highest resolution surface imaging of bulk materials from a scanning microscope and is the only such tool installed in Ireland.

More information at http://www.crann.tcd.ie/index.

My Pittcon Picks: Nanoprobes

I won't make it to Pittcon this year, but in case you'll be in Orlando for the conference next week, here are a few microscopy-related papers I that look important to me. These two both involve nanoprobes, I'll post some more "Pittcon Picks" as I work through the conference program.

Investigations of Translational and Rotational Motions in Living Cells Using Plasmonic Nanoprobes and Differential Interference Contrast Microscopy

Ning Fang, Iowa State University
Studying the rotational motion of biomolecules in living cells is quite a technical challenge, but this type of motion is an important part of endocytosis and intracellular transport. The researchers developed an optical imaging tool that uses plasmonic nanoparticle probes and differential interference contrast (DIC) microscopy to visualize translational and rotational motion of single-nanoparticles in complex environments. The researchers used the new tool to reveal the rotational motions of single gold nanorods during receptor-mediated endocytosis by A549 human lung cancer cells and subsequent intracellular transport on the microtubule network.

Real-time Imaging of Transport and Diffusion of Single Gold Nanoparticles In Vivo

Lauren Browning, Old Dominion University
The researchers synthesized monodisperse gold nanoparticles that were photostabile enough to be used to image transport and diffusion in zebrafish embryos. They used the nanoparticles to study dynamic events during embryonic development at nanometer resolution in real-time.

AFM measures charges of individual atoms

Scientists would like to create devices using molecular-scale manufacturing, but this requires measurement of forces and charges on very small scales. Researchers have now accomplished a feat that could aid such tiny manufacturing by using atomic force microscopy to measure forces on a scale small enough to distinguish neutral atoms from positively and negatively charged ones. 

The work was performed by scientists from IBM’s Zurich Research Laboratory, the University of Regensburg, Germany, and Utrecht University, Netherlands.  Achieving such high-resolution measurements required very high stability. In the June 12 issue of Science, they describe how the required stability was accomplished with a qPlus tuning fork atomic force microscope AFM operated in a vacuum at a very low temperature (5 Kelvin). 

The setup produced measurement conditions stable enough to achieve accuracies of better than 1 piconewton, enough to distinguish the charge of individual atoms. For example, the researchers found the difference in force between a neutral gold atom and that of a gold atom charged with an additional electron to be only about 11 piconewton.

These atomic-scale measurements add to other scientific advances that are aimed at building computing elements that are on the molecular scale, which could create smaller, faster, and more energy-efficient processors and memory devices for tomorrow’s computers.

Free research paper: Measuring the Charge State of an Adatom with Noncontact Atomic Force Microscopy, Leo Gross, Fabian Mohn, Peter Liljeroth, Jascha Repp, Franz J. Giessibl, and Gerhard Meyer, Science 12 June 2009: 1428-1431.

Listen to a podcast interview with author here.

View a video on the research below.

Printed FRET pairs

After reading the headline you may be asking why someone would want to print FRET pairs. After all, FRET is typically used to study dynamic protein interactions. Biological applications are indeed what FRET is known for, however scientists are beginning to see that fluorescent proteins might be useful in fabricated devices such as those used for high-density optical memory and switches. If so, FRET could be a useful way to add functionality to devices making use of fluorescent proteins.

To study this possibility, Vinod Subramaniam and colleagues at the University of Twente in The Netherlands printed 2-D and 3-D patterns of fluorescent protein FRET donor/acceptor pairs. The work is detailed in a recent Langmuir research paper.

By examining the spectra and lifetime of the fluorescent proteins using wide-field fluorescence and confocal microscopy the researchers found that FRET occurred at the interfaces between the donor and acceptor molecules. The researchers point out that fluorescent lifetime imaging microscopy (FLIM) is useful to in making sure the function of the patterned fluorescent proteins is not compromised.

In the future, patterning of FRET pairs could be combined with nanopatterning technology to produce nanoscale devices.

Research paper: FRET Pair Printing of Fluorescent Proteins, Maryana Escalante, Christian Blum, Yanina Cesa, Cees Otto, Vinod Subramaniam, Langmuir Article ASAP