Real-Time Observation of Nanocrystal Growth

August 21, 2009

Interim Berkeley Lab Director Paul Alivisatos and Ulrich Dahmen, director of Berkeley Lab’s National Center for Electron Microscopy (NCEM), led a team of experts in nanocrystal growth and electron microscopy who combined their skills to observe the dynamic growth of colloidal platinum nanocrystals in solution with subnanometer resolution. Their results showed that while some crystals in solution grow steadily in size via classical nucleation and aggregation – meaning molecules collide and join together – others grow in fits and spurts, driven by “coalescence events,” in which small crystals randomly collide and fuse together into larger crystals. Despite their distinctly different growth trajectories, these two processes ultimately yield a nearly monodisperse distribution of nanocrystals, meaning the crystals are all approximately the same size and shape.

A new technique known as “liquid cell in situ transmission electron microscopy,” in which the powerful resolution capabilities of a transmission electron microscope (TEM) are brought to bear on a liquid cell that allows liquids to be observed inside a vacuum, enables the visualization of single nanoparticles in solution. The Berkeley researchers deployed this technique on NCEM’s JEOL 3010 In-Situ microscope. Utilizing an electron beam operating at 300 kilovolts of energy, the JEOL 3010 provides outstanding specimen penetration and spatial resolution of about 8 angstroms through the thick liquid cell sample.

Original publication:

Zheng H, Smith RK, Jun YW, Kisielowski C, Dahmen U, Alivisatos AP (2009): Observation of Single Colloidal Platinum Nanocrystal Growth Trajectories. Science Jun 5;324(5932):1309-12.

http://newscenter.lbl.gov


Mobile Phone Microscopy

Juli 23, 2009

Researchers at the University of California, Berkeley, US have developed the CellScope – a new microscope that can be attached to a common mobile phone with a camera to take color images of microorganisms. The CellScope consists of compact microscope lenses fitted in a holder, which is positioned in front of the mobile phones camera. By using an off-the-shelf phone with a 3.2 megapixel camera, the researchers were able to achieve a spatial resolution of 1.2 micrometers. In this way they were able to capture bright field images of Plasmodium falciparum, the parasite that causes malaria in humans and sickle-shaped red blood cells. They were also able to take fluorescent images of Mycobacterium tuberculosis, the bacterium that causes TB in humans. The development of CellScope moves a major step forward in taking clinical microscopy out of specialized laboratories and into field settings for disease screening and diagnoses. „The same regions of the world that lack access to adequate health facilities are, paradoxically, well-served by mobile phone networks,“ said Dan Fletcher, UC Berkeley associate professor of bioengineering and head of the research team. „We can take advantage of these mobile networks to bring low-cost, easy-to-use lab equipment out to more remote settings.“
www.berkeley.edu

CellScope prototype configured for fluorescent imaging (taken by David Breslauer)

CellScope prototype configured for fluorescent imaging (taken by David Breslauer, UC Berkeley)


Interdisciplinary Symposium on 3D Microscopy

Juni 3, 2009

3D Microscopy, taking place from July 12 -16, 2009 in Interlaken, Switzerland, is an international symposium focused on 3D imaging and spectroscopy in science. The objective of this symposium is to create a forum for researchers with different expertise and scientific interests to present their knowhow and the techniques they use to answer their scientific questions. Methods using three-dimensional imaging and spectroscopy to retrieve data in volume will be discussed, whether “light”, x-rays, electrons or near field probes are used. The conference contains 3 plenary talks and 9 sessions with invited and contributed talks and poster sessions.

Session topics are:

– High resolution TEM and AFM
– 3D CLSM and light microscopy
– Stereology
– 3D TEM and atom probe tomography/serial sectioning
– 3D correlative microscopy
– 3D X-ray microscopy and tomography
– 3D FIB/SEM or serial sectioning (with Denk-method) blockface tomography
– 3D image analysis and simulation
– 3D scanning probe microscopy

www.ssom.ch/3D/index.html

Interlaken, Switzerland

Interlaken, Switzerland


Frontiers of Electron Microscopy in Materials Sciences

Mai 25, 2009

The Twelfth Frontiers of Electron Microscopy in Materials Science, FEMMS2009, will take place from Sept. 27 – Oct. 2, 2009 at “Huis Ten Bosch” in Sasebo/Nagasaki in Kyushu Island, Japan. FEMMS is an international a biennial symposium series focused on the application of electron microscopy, primarily TEM, in the field of materials science. The conference contains a plenary talk, 9 sessions of invited talks and poster sessions of contributed papers. The sessions cover recent progresses and emerging trends, such as current instrument advances in TEM, SEM, HVEM and detecting systems, ultra-high resolution imaging and analysis, in-situ and ultra-fast analysis, 3-dimensional analysis, and so on. Dr. Akira Tonomura, a world renowned pioneer in the field of electron holography, will give a plenary talk as the distinguished lectureship award winner.
www.femms2009.org

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Live Cell Imaging at Double the Resolution

Mai 6, 2009

A team of researchers of the University of Georgia (UGA) and the University of California, San Francisco, US has developed a microscope that is capable of live imaging at double the resolution of fluorescence microscopy by using structured illumination. The research was published in Nature Methods on April 26, 2009. “What we’ve done is develop a much faster system that allows you to look at live cells expressing the green fluorescent protein (GFP), which is a very powerful tool for labeling inside the cell,” explained UGA engineer Peter Kner.
www.engineering.uga.edu


Focus on Microscopy 2009

Januar 9, 2009

From Sunday April 5 to Wednesday April 8, 2009 the Focus on Microscopy (FOM) conference will take place in Krakow, Poland. It is the continuation of a yearly conference series presenting the latest innovations in optical microscopy and its application in biology, medicine and the material sciences. Key subjects are the theory and practice of 3D optical imaging, related 3D image processing, and reporting especially on developments in resolution and imaging modalities. The FOM conference also covers the rapidly advancing fluorescence labeling techniques for the confocal and multiphoton 3D imaging of live- biological-specimens. A technical exhibition will be a special feature of this year’s conference in Krakow.

Upcoming topics will cover:
– Confocal and multiphoton-excitation microscopy
Novel illumination and detection strategies
– Fluorescence: new labels, fluorescent proteins, quantum dots, single molecule

– Time-resolved fluorescence: FRET, FRAP, FLIM, FCS

– Coherent non-linear microscopy: SHG, THG, SFG, CARS

– Raman, light scattering microscopy

– Multi-dimensional imaging

– Sub-wavelength resolution: near field microscopy, STED, PALM

– Laser manipulation, ablation and microdissection, photoactivation

– Optical tools in genomics, proteomics, phenomics, cytometry

– Magnetic resonance and X-ray microscopy

– Image processing and visualization

– Live cell and whole tissue imaging

The conference will take place at the Jagiellonian University Auditorium Maximum, ul. Krupnicza 35, in the center of Krakow.

Details for registration, abstract submission, deadlines, etc. will soon be available on:
www.focusonmicroscopy.org

Krakow, Poland, source: pixelio.de

Krakow, Poland (source: pixelio.de)