Improved ultrasound capabilities with nanoscale imaging agents made by microbes

March 17, 2014 by Deborah Williams-Hedges

Dr. Mikhail Shapiro was interested in developing nanoscale imaging agents for ultrasound to enable non-invasive imaging of a much broader range of biological and biomedical events in the body. Turning to nature for inspiration, he and his colleagues at Caltech and UC Berkeley, successfully created the first ultrasound imaging agent based on genetically encoded gas-containing structures.

Shapiro's team utilized photosynthetic micro-organisms that form gas nanostructures called "gas vesicles," that the researchers discovered were excellent for ultrasound, with several unique properties making them especially useful in .

This new nanotechnology method opens the door to a broad variety of potential imaging applications where the nanometer size is advantageous, (e.g., in labeling targets outside the bloodstream), and could have a significant impact on ultrasounds - one of the most widely used imaging modalities in biomedicine.

Previously, most agents were based on small gas bubbles, which ultrasound can detect because they have a different density than their surroundings and can resonate with sound waves. Unfortunately, these "microbubbles" could only be synthesized at sizes of several microns (or larger) because of their fundamental physics: the smaller you tried to make them, the less stable they became. As a result, they were always confined to the bloodstream and could only image a limited number of biological targets.

The researchers wanted to find another way of making gas-filled structures that could be nanoscale. In particular, certain photosynthetic micro-organisms regulate their buoyancy by forming protein-shelled gas nanostructures called "gas vesicles" inside the cell body. These structures interact with gas in a way that is fundamentally different from microbubbles, allowing them to have nanometer size. In this study, they discovered that gas vesicles are excellent imaging agents for ultrasound.

The researchers showed that they were able to easily attach biomolecules to the gas vesicle surface to enable targeting. In addition, because these structures are encoded as genes, they now have a chance to modify these genes to optimize gas vesicles' ultrasound properties. Already the team has shown that gas vesicles from different species, which vary in genetic sequence, exhibit different properties that can be used to, for example, distinguish them from each other in an image.

Explore further: Researchers solve nano mystery

Related Stories

Researchers solve nano mystery

February 7, 2014

A technique which may one day be used for tumor therapy and imaging could be greatly improved thanks to new insights obtained by scientists from the University of Twente, the Erasmus MC and the TU Delft.

A breakthrough in medical acoustics

January 27, 2014

Researchers at the University of Twente, Delft University of Technology (TU Delft) and Erasmus MC (University Medical Center Rotterdam) have achieved a breakthrough in the field of medical ultrasound. Ultrasound irradiation ...

Recommended for you

Graphene photodetector enhanced by fractal golden 'snowflake'

January 16, 2017

(Phys.org)—Researchers have found that a snowflake-like fractal design, in which the same pattern repeats at smaller and smaller scales, can increase graphene's inherently low optical absorption. The results lead to graphene ...

Nanoscale view of energy storage

January 16, 2017

In a lab 18 feet below the Engineering Quad of Stanford University, researchers in the Dionne lab camped out with one of the most advanced microscopes in the world to capture an unimaginably small reaction.

Scientists create first 2-D electride

January 11, 2017

(Phys.org)—Researchers have brought electrides into the nanoregime by synthesizing the first 2D electride material. Electrides are ionic compounds, which are made of negative and positive ions. But in electrides, the negative ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.