q&more
My watch list
my.chemie.de  
Login  

News

How much does life weigh?

New cell scale with high resolution

qimono, pixabay.com, CC0

27-Oct-2017: ETH researchers have developed a scale for measuring cells. It allows the weight of individual living cells, and any changes in this weight, to be determined quickly and accurately for the first time. The invention has also aroused significant interest both in and outside the field of biology.

From earthworms and sunflowers to human beings, we are all made up of cells, so it’s no surprise that researchers are hard at work investigating these building blocks of life. They have already discovered many of their secrets, but until now, it has not been possible to measure the weight of living cells and how it changes in real time, as no suitable method of measurement has existed.

New cell scale with high resolution

That has now changed: in collaboration with Christoph Gerber and Sascha Martin from the University of Basel and Jason Mercer from University College London, scientists from the biophysics research group, led by ETH professor Daniel J Müller, have developed a novel cell scale. This not only enables them to measure the mass of living cells within a very short time, but also to monitor how their weight changes over time. They can do so with a resolution of milliseconds and trillionths of a gram.

The cells, which usually weigh about two to three nanograms, are weighed under controlled conditions in a cell culture chamber. The weighing arm, a tiny wafer-thin, transparent silicon cantilever coated with collagen or fibronectin, is lowered to the floor of the chamber, where it nudges and picks up a cell. “The cell hangs on the underside of a tiny cantilever for the measurements,” says doctoral student Gotthold Fläschner, who co-invented and conducted most experiments using the new scale.

Observing weight and cell activity at the same time

The microscopic cantilever is induced to oscillate slightly by means of a pulsing blue laser at its fixed end. A second, infrared laser measures the oscillations at the other end, where the cell hangs – first without and then with the cell. “The cell’s mass can be calculated from the difference between the two oscillations,” explains David Martínez-Martín, main inventor of the cell scale.

A computer screen shows the changing weight as a curve. Readings can be taken from this over the whole measuring period – whether that’s milliseconds or days. As the measuring apparatus, including the cell culture, is mounted directly on the object plate of a high-performance fluorescence microscope, internal processes in the cell can also be observed and filmed while measurements take place.

Weight of living cells fluctuates

This allows researchers to track, for example, how the weight changes during the cell cycle and cell division, the influence various substances have on the cell’s mass, and what happens when it is infected by a virus. Martínez-Martín and Fläschner have carried out many such experiments.

One particularly noteworthy observation: “We established that the weight of living cells fluctuates continuously by about one to four percent as they regulate their total weight,” says Martínez-Martín. Measuring errors have been ruled out: the biophysicists were able to prove that cells only stop these second-by-second fluctuations upon dying. The researchers are visibly excited. Fläschner: “We’re seeing things that nobody else has yet observed.”

High interest in cell scale

There’s always high interest when ETH scientists report on a new development. “A cell’s mass is a very good indicator of its physiology,” explains Martínez-Martín. So it makes sense that biologists of all stripes are interested in the new measuring method. It may also be relevant to the medical and pharmaceutical sectors, as it could be used to investigate the pathological growth of cells and the influence of drugs on this growth.

More surprisingly, material scientists are also interested in the device. “For them, it’s about the functionalisation of nanoparticles – in other words, changing the surface of very small particles,” states Martínez-Martín.

The scientists are now introducing their invention to a broad scientific audience for the first time in the journal Nature. The new weighing method has been patented; nonetheless, the chances that scientists of various disciplines will soon be able to use the promising new cell scale themselves are good. The licensee, Swiss company Nanosurf AG, is already working to put the device into production.

Original publication:
Martínez-Martín D, Fläschner G, Gaub B, Martin D, Newton R, Beerli C, Mercer J, Gerber C, Müller DJ; "Inertial picobalance reveals fast mass fluctuations of mammalian cells"; Nature; published online 25th Oct 2017

Facts, background information, dossiers

  • cell scales

More about ETH Zürich

  • News

    Sticking sugar to protein

    Whenever cells receive signals, interact with other cells or identify viruses and bacteria, the process involves not only proteins but also sugar chains attached to their surface. The subject of relatively little attention until now, these structures differ widely in composition and branchi ... more

    Brain signals for drug screening

    An international team led by ETH researchers has developed a technique that uses electrical brain signals to more precisely evaluate the effect of drugs on the brain. It could be of particular use in the early development phase of anti-epilepsy medication. There are still comparatively few ... more

    Quantum cocktail provides insights on memory control

    The speed of writing and reading out magnetic information from storage devices is limited by the time that it takes to manipulate the data carrier. To speed up these processes, researchers have recently started to explore the use of ultrashort laser pulses that can switch magnetic domains i ... more

  • q&more articles

    Investment for the Future

    This is a very particular concern and at the same time the demand placed annually on Dr. Irmgard Werner, who, as a lecturer at the ETH Zurich, supports around 65 pharmacy students in the 5th semester practical training in “pharmaceutical analysis”. With joy and enthusiasm for her subject sh ... more

    Analysis in picolitre volumes

    Reducing time, costs and human resources: many basic as well as applied analytical and diagnostic challenges can be performed on lab-on-a-chip systems. They enable sample quantities to be reduced, work steps to be automated and completed in parallel, and are ideal for combination with highl ... more

  • Authors

    Prof. Dr. Petra S. Dittrich

    Petra Dittrich is an Associate Professor in the Department of Biosystems Science and Engineering at ETH Zurich (Switzerland). She studied chemistry at Bielefeld University and the University of Salamanca (Spain). After completing her doctoral studies at the Max Planck Institute for Biophysi ... more

    Dr. Felix Kurth

    Felix Kurth studied bioengineering at the Technical University Dortmund (Germany) and at the Royal Institute of Technology in Stockholm (Sweden). During his PhD studies at ETH Zurich (Switzerland), which he completed in 2015, he developed lab-on-a-chip systems and methods for quantifying me ... more

    Lucas Armbrecht

    Lucas Armbrecht studied microsystems technology at the University of Freiburg (Breisgau, Germany). During his master’s, he focused on sensors & actuators and lab-on-a-chip systems. Since June 2015, he is PhD student in the Bioanalytics Group at ETH Zurich (Switzerland). In his doctoral stud ... more

q&more – the networking platform for quality excellence in lab and process

The q&more concept is to increase the visibility of recent research and innovative solutions, and support the exchange of knowledge. In the broad spectrum of subjects covered, the focus is on achieving maximum quality in highly innovative sectors. As a modern knowledge platform, q&more offers market participants one-of-a-kind networking opportunities. Cutting-edge research is presented by authors of international repute. Attractively presented in a high-quality context, and published in German and English, the original articles introduce new concepts and highlight unconventional solution strategies.

> more about q&more

q&more is supported by:



Your browser is not current. Microsoft Internet Explorer 6.0 does not support some functions on Chemie.DE