World's smallest sensor measures growth force of plants, animals and humans

January 29, 2018, Wageningen University
Credit: Wageningen University & Research

How do you visualise the extremely small forces connected to processes such as embryonic growth and development? Researchers at Wageningen have experimented with a combination of laser technology and chemistry, coming up with a sensor consisting of one single molecule that is a few hundred times more accurate than existing devices used to measure nano-forces on the molecular level. The researchers describe their findings in the 18 January issue of the scientific journal Chem.

The forces experienced by in cells, but also in all the materials around us, are so small that even the most accurate existing measuring devices are barely able to detect whether it is a at all. "Until now, everything was black or white, either there was a force or there wasn't—existing methods couldn't determine anything in between," says Joris Sprakel, research group leader at Sprakel Lab and the Physical Chemistry and Soft Matter Group of Wageningen University & Research. "With a team of three young researchers and an advanced student we've brought together various areas of expertise. And we came up with the idea that it had to be theoretically possible to detect the forces at by using the molecule itself as a nano measuring . We no longer measure black or white, but 'fifty shades of grey' so to speak."

Expressed in technical terms, sensing the force of one molecule has a resolution of 100 femtonewtons. As a force, this is written as 0.0000000000001 newton (1 newton feels like around 100 grams). "But a molecule is also unbelievably small, about one nanometre, or one millionth of a millimetre," says Joris Sprakel. "This force of one hundred femtonewtons that presses on a molecule of one nanometre can be compared with the force of a grain of sand on a person's shoulder. And we can measure such small forces with the relationships that are a billion times smaller."

Using the new measuring method, the researchers gained more insight into the forces that are active on a molecular level in the living cells of plants, animals and humans. "For example, in the embryonic development of plant , we know that miniscule forces determine when a cell divides and in which direction. So ultimately, these mechanical stimuli determine how the plant embryo develops, but until now it wasn't possible to measure this," says Sprakel. "Previously, we had no direct access to physical phenomena on this scale, and if you can't see it, it's almost impossible to understand how it works. If you understand the role of nano-forces in biological processes, in the long term, it may be possible to prevent certain diseases due to errors in these cell forces. But this is still something for the future; we've now demonstrated how we can measure these kinds of 'unmeasurable' forces. In my team, we are currently working on applying this approach to cellular processes."

Molecule as measuring device

According to Joris Sprakel, taking these kinds of sensitive, small-scale measurements are not possible using a large measuring device in a cell. The researchers therefore created molecules that act as measuring devices. Each of the molecular sensors made by the team works as a nano-force metre. To measure the molecule and determine the force, the researchers shine a laser on one molecule. This molecule returns the light in a different shade, allowing the research team to determine the amount of force. Crucially, therefore, the method does not only consist of a new molecule or a new instrument, but of a combination of the two.

"We needed a strong interdisciplinary team for this," says Sprakel. "This breakthrough was achieved by the unique combination of four young researchers in my team, each with their own area of expertise. It meant we were finally able to realise this long-cherished dream."

Explore further: Bubble technique used to measure shear forces between graphene sheets

More information: Ties van de Laar et al. Light from Within: Sensing Weak Strains and FemtoNewton Forces in Single Molecules, Chem (2018). DOI: 10.1016/j.chempr.2017.12.016

Related Stories

Measuring small forces that lead to large effects

December 7, 2017

Forces between individual particles in slurries are responsible for their rheological behavior. Direct quantification of physical forces between mineral faces is now possible with atomic force microscopy, thanks to work at ...

Researchers discover switching function in molecular wire

October 27, 2017

The increasing miniaturisation in electronics will result in components which consist of only a few molecules, or even just one molecule. Tiny wires are required to connect these to an electrical circuit at the nano level. ...

Recommended for you

Archaeologists discover Incan tomb in Peru

February 16, 2019

Peruvian archaeologists discovered an Incan tomb in the north of the country where an elite member of the pre-Columbian empire was buried, one of the investigators announced Friday.

Where is the universe hiding its missing mass?

February 15, 2019

Astronomers have spent decades looking for something that sounds like it would be hard to miss: about a third of the "normal" matter in the Universe. New results from NASA's Chandra X-ray Observatory may have helped them ...

What rising seas mean for local economies

February 15, 2019

Impacts from climate change are not always easy to see. But for many local businesses in coastal communities across the United States, the evidence is right outside their doors—or in their parking lots.

The friendly extortioner takes it all

February 15, 2019

Cooperating with other people makes many things easier. However, competition is also a characteristic aspect of our society. In their struggle for contracts and positions, people have to be more successful than their competitors ...


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.