New microfluidic chip can generate microbubbles to break open cells for biochemical analysis

March 15, 2012
Micrographs of GFP-expressing bacteria before and after lysis

Scientists have made many important discoveries in biology and medicine through studying the internal contents of cells. Some have isolated or identified nucleic acids or proteins with special functions, while others have unravelled the working and regulatory mechanisms underlying biochemical or pharmaceutical components within cells. Dave Ow and co-workers at the A*STAR Bioprocessing Technology Institute and Institute of High Performance Computing have now developed a novel method to expose the internal contents of cells for biochemical analysis.

Currently there is a wide range of methods to disintegrate or lyse cell membranes and to release the contained within. However, most of these methods can cause denaturation of proteins or interfere with subsequent assaying. Ow and co-workers explored the possibility of using ultrasound in microfluidics to lyse cells. They applied short bursts of ultrasound with periods of rest to prevent the proteins from overheating as a result of dissipation of .

When the rapid changes of pressure generated with ultrasound are applied to a liquid, small bubbles are formed which oscillate in size and generate a cyclic shear stress. These rapidly oscillating bubbles generate a mini shockwave when they implode, which can be strong enough to cause the to rupture. The researchers generated microbubbles in the meandering microfluidic channel by introducing a gas via a separate inlet to generate a gas–liquid interface and subsequently applying ultrasound to the system.

As a proof of principle, the researchers tested the performance of their microfluidic device on genetically engineered bacteria and yeast that express the green fluorescent protein. The researchers found that the bacteria are completely disintegrated after only 0.4 seconds of ultrasound exposure (see image). The concentration of DNA released from yeast cells reached a plateau after only one second exposure (which contained six bursts of ultrasound each of 0.154 seconds), indicating that most cells are successfully lysed. Importantly the temperature of the sample was shown not to rise above 3.3 °C. “The large surface to volume ratio of the environment means that the small amount of heat that is generated rapidly diffuses away,” says Ow.

The researchers have proposed many ideas for applications. “In collaboration with another institute, we are developing a rapid and sensitive label-free optical method for on-chip detection of bioanalytes from lysed cells,” says Ow. “We also want to modify the device to break more difficult-to-lyse endospores, and to develop a rapid on-chip detection device to counter the threats of bioterrorism.”

Explore further: Research shows how ultrasound can deliver therapeutic molecules into living cells

More information: Research article in Lab on a chip

Related Stories

Bursting bubbles with sound offers new treatments for cancer

June 28, 2010

A new way to deliver cancer drugs using gas bubbles and sound waves is to be developed at the University of Leeds. The project will enable highly toxic drugs to be delivered in small doses directly to tumours, where their ...

New imaging technology enlightened by biomedical engineering

October 19, 2010

A Faculty of Engineering professor is conducting biomedical research that could have profound effects on medical imaging and the delivery of drugs by using light and ultrasound. Roger Zemp, a professor in the Department of ...

DNA 'off switch' may reverse premature aging

June 15, 2011

The secret to preventing or reversing premature aging may be found in a DNA “off switch” that humans share with common yeast, according to new research from the University of Toronto.

Recommended for you

Study reveals how nanochannels select potassium ions

August 25, 2015

(Phys.org)β€”One of the mysteries in biology is how cells can selectively diffuse potassium across a membrane. Biological systems rely on a delicate balance between these potassium and sodium ion concentrations in the surrounding ...

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.