Hop, skip and a jump: Researchers reveal molecular search patterns

March 7, 2016, University of Colorado at Boulder

Like an albatross scanning for pods of squid in a vast ocean, molecules on solid surfaces move in an intermittent search pattern that provides maximum efficiency, according to new research from the University of Colorado Boulder.

While this behavior had been proposed theoretically, CU-Boulder researchers have made the first experimental observations of this phenomenon, providing a gateway for potential improvements in fields ranging from medical diagnostics to chemical production.

"Cutting-edge technologies like lab-on-a-chip devices and biosensors rely on quickly and effectively interacting with the targets they're seeking," said Professor Daniel Schwartz of the Department of Chemical and Biological Engineering. "By better understanding exactly what's happening at the molecular level, we can enhance or engineer technologies that operate faster and more efficiently. Possible outcomes might include a more robust response to disease markers, a less wasteful technique for commercial chemical production or any number of other advances."

The research, conducted by Schwartz and Jon Monserud, a PhD candidate in the Department of Chemical and Biological Engineering, was recently published in the journal Physical Review Letters.

In nature and society, everything from predatory animals to submarine-seeking ships has developed search strategies where slow, localized searches alternate with long, non-searching movements to explore vast areas where targets are sparse, Schwartz said. When prey is abundant, a simple random walking method is a better way to make connections.

Researchers wondered if molecules would behave the same way.

To examine the theory, researchers used single-molecule tracking to directly observe the search process of DNA on surfaces decorated with complementary DNA and witnessed periods of slow motion punctuated by fast hops through an adjacent liquid phase.

By measuring how long it took for each molecule to find its target, researchers determined that the tiny particles were indeed using the same intermittent-flight foraging techniques as a shark hunting for prey or a honeybee seeking nectar. This strategy allowed them to find targets more than 10 times faster than they would have using a simple random walk search.

"It's an incredible coincidence that molecules are exhibiting the same counterintuitive methods that animals and humans have evolved or chosen to use," said Monserud. "We can exploit this coincidence to improve a wide range of technologies."

In the medical field, for example, detection tests for scores of diseases rely on biomarkers such as antibodies or mutated DNA reacting to probe molecules on surfaces to inform doctors of the presence or severity of a malady.

The researchers demonstrated that molecules searched more quickly on hydrophobic surfaces, indicating that developers of DNA biosensors could benefit from tailoring their diagnostic products to have more water-averse surfaces. The findings may result in quicker diagnoses, individually tailored healthcare, and potentially, better outcomes for patients.

The findings could also optimize industrial production to reduce energy, time, materials and costs. In many industrial processes, raw materials are converted to fuels, pharmaceuticals or through chemical reactions, then separated from the remaining waste. Both the reactions and purification processes require molecules to scan surfaces and bind to targets through the same intermittent searching behavior.

"In a sense, our findings help explain why these technologies surprisingly work as well as they do," Schwartz said. "But additionally, developing this understanding can potentially help us design even better technologies since, until now, people have always assumed that molecules searched in a different manner."

Explore further: Surfing water molecules could hold the key to fast and controllable water transport

More information: Jon H. Monserud et al. Interfacial Molecular Searching Using Forager Dynamics, Physical Review Letters (2016). DOI: 10.1103/PhysRevLett.116.098303

Related Stories

'Swiss army knife' molecule

February 16, 2016

Scientists at ETH Zurich and an ETH spin-off have developed a novel polymer for coating materials, in order to prevent biofilms from forming on their surfaces. Thanks to the technological platform developed, it is now possible ...

Counting molecules with an ordinary cell phone

February 24, 2016

Diagnostic health care is often restricted in areas with limited resources, because the procedures required to detect many of the molecular markers that can diagnose diseases are too complex or expensive to be used outside ...

Scrutinising the tip of molecular probes

February 29, 2016

Studies of molecules confined to nano- or micropores are of considerable interest to physicists. That's because they can manipulate or stabilise molecules in unstable states or obtain new materials with special properties. ...

Recommended for you

Walking crystals may lead to new field of crystal robotics

February 23, 2018

Researchers have demonstrated that tiny micrometer-sized crystals—just barely visible to the human eye—can "walk" inchworm-style across the slide of a microscope. Other crystals are capable of different modes of locomotion ...

Researchers turn light upside down

February 23, 2018

Researchers from CIC nanoGUNE (San Sebastian, Spain) and collaborators have reported in Science the development of a so-called hyperbolic metasurface on which light propagates with completely reshaped wafefronts. This scientific ...

Seeing nanoscale details in mammalian cells

February 23, 2018

In 2014, W. E. Moerner, the Harry S. Mosher Professor of Chemistry at Stanford University, won the Nobel Prize in chemistry for co-developing a way of imaging shapes inside cells at very high resolution, called super-resolution ...

Recurrences in an isolated quantum many-body system

February 23, 2018

It is one of the most astonishing results of physics—when a complex system is left alone, it will return to its initial state with almost perfect precision. Gas particles, for example, chaotically swirling around in a container, ...

Hauling antiprotons around in a van

February 22, 2018

A team of researchers working on the antiProton Unstable Matter Annihilation (PUMA) project near CERN's particle laboratory, according to a report in Nature, plans to capture a billion antiprotons, put them in a shipping ...

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.