Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New microscopy technique offers close-up, real-time view of cellular phenomena

15.03.2010
MIT scientists record first microscopic images showing deadly effects of AMPs

For two decades, scientists have been pursuing a potential new way to treat bacterial infections, using naturally occurring proteins known as antimicrobial peptides (AMPs). Now, MIT scientists have recorded the first microscopic images showing the deadly effects of AMPs, most of which kill by poking holes in bacterial cell membranes.

Researchers in the laboratory of MIT Professor Angela Belcher modified an existing, extremely sensitive technique known as high-speed atomic force microscopy (AFM) to allow them to image the bacteria in real time. Their method, described in this Sunday's online edition of Nature Nanotechnology, represents the first way to study living cells using high-resolution images recorded in rapid succession.

Using this type of high-speed AFM could allow scientists to study how cells respond to other drugs and to viral infection, says Belcher, the Germeshausen Professor of Materials Science and Engineering and Biological Engineering. The new work could also help researchers understand how some bacteria can become resistant to AMPs (none of which have been approved as drugs yet).

Atomic force microscopy, invented in 1986, is widely used to image nanoscale materials. Its resolution is similar to that of electron microscopy, but unlike electron microscopy, it does not require a vacuum and thus can be used with living samples. However, traditional AFM requires several minutes to produce one image, so it cannot record a sequence of rapidly occurring events.

In recent years, scientists have developed high-speed AFM techniques, but haven't optimized them for living cells. That's what the MIT team set out to do, building on the experience of lead author Georg Fantner, a postdoctoral associate in Belcher's lab who had worked on high-speed AFM at the University of California at Santa Barbara.

How they did it: Atomic force microscopy makes use of a cantilever equipped with a probe tip that "feels" the surface of a sample. Forces between the tip and the sample can be measured as the probe moves across the sample, revealing the shape of the surface. The MIT team used a cantilever about 1,000 times smaller than those normally used for AFM, which enabled them to increase the imaging speed without harming the bacteria.

With the new setup, the team was able to take images every 13 seconds over a period of several minutes. They found that AMP-induced cell death appears to be a two-step process: a short incubation period followed by a rapid "execution." They were surprised to see that the onset of the incubation period varied from 13 to 80 seconds.

"Not all of the cells started dying at the exact same time, even though they were genetically identical and were exposed to the peptide at the same time," says Roberto Barbero, a graduate student in biological engineering and an author of the paper.

Next steps: In the future, Belcher hopes to use atomic force microscopy to study other cellular phenomena, including the assembly of viruses in infected cells, and the effects of traditional antibiotics on bacterial cells. The technique may also prove useful in studying mammalian cells.

Funding: Erwin-Schrodinger Fellowship, National Institutes of Health, Army Research Office, Austrian Research Promotion Agency.

Source: "Kinetics of antimicrobial peptide activity measured on individual bacterial cells using high-speed atomic force microscopy," Georg Fantner, Roberto Barbero, David Gray and Angela Belcher. "Nature Nanotechology, March 14, 2010.

Jen Hirsch | EurekAlert!
Further information:
http://www.mit.edu

More articles from Medical Engineering:

nachricht Medical gamma-ray camera is now palm-sized
23.05.2017 | Waseda University

nachricht Computer accurately identifies and delineates breast cancers on digital tissue slides
11.05.2017 | Case Western Reserve University

All articles from Medical Engineering >>>

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 >>>