Nanotechnology Now

Our NanoNews Digest Sponsors


Heifer International

Wikipedia Affiliate Button

Home > Press > INBT researchers use LEGO to study what happens inside lab-on-a-chip devices

German Drazer, asst. prof. of ChemBE, shows how a LEGO set-up can explain forces in mircofluidic arrays. (Will Kirk/JHU)
German Drazer, asst. prof. of ChemBE, shows how a LEGO set-up can explain forces in mircofluidic arrays. (Will Kirk/JHU)

Abstract:
Johns Hopkins engineers are using a popular children's toy to help them visualize the behavior of particles, cells and molecules in environments too small to see with the naked eye.

INBT researchers use LEGO to study what happens inside lab-on-a-chip devices

Baltimore, MD | Posted on December 2nd, 2009

These researchers are arranging little LEGO pieces shaped like pegs to recreate microscopic activity taking place inside lab-on-a-chip devices at a scale they can more easily observe. These lab-on-a-chip devices, also known as microfluidic arrays, are commonly used to sort tiny samples by size, shape or composition, but the minuscule forces at work at such a small magnitude are difficult to measure. To solve this small problem, the Johns Hopkins engineers decided to think big.

Led by Joelle Frechette and German Drazer, both assistant professors of chemical and biomolecular engineering in the Whiting School of Engineering, the team used beads just a few millimeters in diameter, an aquarium filled with goopy glycerol and the LEGO pieces arranged on a LEGO board to unlock mysteries occurring at the micro- or nanoscale level. Their observations could offer clues on how to improve the design and fabrication of lab-on-a-chip technology. Their study concerning this technique was published in the August 14 issue of Physical Review Letters. Both Drazer and Frechette are affiliated faculty members of Johns Hopkins Institute for NanoBioTechnology.

The idea for this project comes from the concept of "dimensional analysis," in which a process is studied at a different size and time scale while keeping the governing principles the same.

"Microfluidic arrays are like miniature chemical plants," Frechette says. "One of the key components of these devices is the ability to separate one type of constituent from another. We investigated a microfluidic separation method that we suspected would remain the same when you scale it up from micrometers or nanometers to something as large as the size of billiard balls."

With this goal in mind, Frechette and Drazer constructed an array using cylindrical LEGO pegs stacked two high and arranged in rows and columns on a LEGO board to create a lattice of obstacles. The board was attached to a Plexiglas sheet to improve its stiffness and pressed up against one wall of a Plexiglas tank filled with glycerol. Stainless steel balls of three different sizes, as well as plastic balls, were manually released from the top of the array. Their paths to the bottom were tracked and timed with a camera.

The entire set-up, Drazer said, cost a few hundred dollars and could easily be replicated as a science fair experiment.

Graduate students Manuel Balvin and Tara Iracki, and undergraduate Eunkyung Sohn, all from the Department of Chemical and Biomolecular Engineering, performed multiple trials using each type of bead. They progressively rotated the board, increasing the relative angle between gravity and the columns of the array (that is, altering the forcing angle). In doing so, they saw that the large particles did not move through the array in a diffuse or random manner, as their small counterparts usually did in a microfluidic array. Instead, their paths were deterministic, meaning that they could be predicted with precision, Drazer said.

The researchers also noticed that the path followed by the balls was periodic once the balls were in motion and coincided with the direction of the lattice. As the forcing angle increased, some of the balls tended to shift over one, two, three or as many as four pegs before continuing their vertical fall.

"Our experiment shows that if you know one single parameter—a measure of the asymmetry in the motion of a particle around a single obstacle—you can predict the path that particles will follow in a microfluidic array at any forcing angle, simply by doing geometry." Drazer said.

The fact that the balls moved in the same direction inside the array for different forcing angles is referred to as phase-locking. If the array were to be scaled down to micro- or nanosize, the researchers said they would expect these phenomena to still be present and even increase depending on the factors such as the unavoidable irregularities of particle size or surface roughness.

"There are forces present between a particle and an obstacle when they get really close to each other, which are present whether the system is at the micro- or nanoscale or as large as the LEGO board," Frechette said. "In this separation method, the periodic arrangement of the obstacles allows the small effect of these forces to accumulate, and amplify, which we suspect is the mechanism for particle separation."

This principle could be applied to the design of micro- or nanofluidic arrays, she added, so that they could be fabricated to "sort particles that had a different roughness, different charge or different size. They should follow a different path in an array and could be collected separately."

Phase-locking is likely to become less important, Drazer cautioned, as the number of particles in solution becomes more concentrated. "Next," he said, "we have to look at how concentrated your suspension can be before this principle is destroyed by particle-particle interactions."

The research was funded by grants from the National Science Foundation and the American Chemical Society Petroleum Research Fund.

Reference: "Directional locking and the role of irreversible interactions in deterministic hydrodynamics separations in microfluidic devices" Manuel Balvin, Eunkyung Sohn, Tara Iracki, German Drazer, and Joelle Frechette, Phys. Rev. Lett. 103, 078301 (2009).

Story by Mary Spiro

####

About Johns Hopkins
The Institute for NanoBioTechnology at Johns Hopkins University brings together 193 researchers from: Bloomberg School of Public Health, Krieger School of Arts and Sciences, School of Medicine, Applied Physics Laboratory, and Whiting School of Engineering to create new knowledge and new technologies at the interface of nanoscience and medicine.

For more information, please click here

Contacts:
For media inquiries contact:
Mary Spiro

410 516-4802

Copyright © Johns Hopkins

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Ageing can drive progress: Population ageing is likely to boost medicine, nanotechnology and robotics, but increase political risks July 27th, 2016

WSU researchers 'watch' crystal structure change in real time: Breakthrough made possible by new Argonne facility July 27th, 2016

Enhancing molecular imaging with light: New technology platform increases spectroscopic resolution by 4 fold July 27th, 2016

New nontoxic process promises larger ultrathin sheets of 2-D nanomaterials July 27th, 2016

Videos/Movies

New remote-controlled microrobots for medical operations July 23rd, 2016

Scientists glimpse inner workings of atomically thin transistors July 21st, 2016

Graphene photodetectors: Thinking outside the 2-D box July 21st, 2016

A 'bridge' of carbon between nerve tissues: A high-tech 'sponge' connects neurons in vitro (and is biocompatible in vivo) July 18th, 2016

Electricity generated with water, salt and a 3-atoms-thick membrane: EPFL researchers have developed a system that generates electricity from osmosis with unparalleled efficiency. Their work, featured in Nature, uses seawater, fresh water, and a new type of membrane just 3 atoms July 15th, 2016

Microfluidics/Nanofluidics

Researchers invent 'smart' thread that collects diagnostic data when sutured into tissue: Advances could pave way for new generation of implantable and wearable diagnostics July 18th, 2016

Droplets finally all the same size -- in a nanodroplet library June 20th, 2016

NanoLabNL boosts quality of research facilities as Dutch Toekomstfonds invests firmly June 10th, 2016

Possible Futures

Ageing can drive progress: Population ageing is likely to boost medicine, nanotechnology and robotics, but increase political risks July 27th, 2016

Enhancing molecular imaging with light: New technology platform increases spectroscopic resolution by 4 fold July 27th, 2016

New nontoxic process promises larger ultrathin sheets of 2-D nanomaterials July 27th, 2016

Scientists test nanoparticle drug delivery in dogs with osteosarcoma July 26th, 2016

Nanomedicine

Scientists test nanoparticle drug delivery in dogs with osteosarcoma July 26th, 2016

The NanoWizard® AFM from JPK is applied for interdisciplinary research at the University of South Australia for applications including smart wound healing and how plants can protect themselves from toxins July 26th, 2016

Accurate design of large icosahedral protein nanocages pushes bioengineering boundaries: Scientists used computational methods to build ten large, two-component, co-assembling icosahedral protein complexes the size of small virus coats July 25th, 2016

New superconducting coil improves MRI performance: UH-led research offers higher resolution, shorter scan time July 23rd, 2016

Announcements

Ageing can drive progress: Population ageing is likely to boost medicine, nanotechnology and robotics, but increase political risks July 27th, 2016

WSU researchers 'watch' crystal structure change in real time: Breakthrough made possible by new Argonne facility July 27th, 2016

Enhancing molecular imaging with light: New technology platform increases spectroscopic resolution by 4 fold July 27th, 2016

New nontoxic process promises larger ultrathin sheets of 2-D nanomaterials July 27th, 2016

Grants/Awards/Scholarships/Gifts/Contests/Honors/Records

Scientists test nanoparticle drug delivery in dogs with osteosarcoma July 26th, 2016

Ultra-flat circuits will have unique properties: Rice University lab studies 2-D hybrids to see how they differ from common electronics July 25th, 2016

Accurate design of large icosahedral protein nanocages pushes bioengineering boundaries: Scientists used computational methods to build ten large, two-component, co-assembling icosahedral protein complexes the size of small virus coats July 25th, 2016

New reaction for the synthesis of nanostructures July 21st, 2016

Nanobiotechnology

Scientists test nanoparticle drug delivery in dogs with osteosarcoma July 26th, 2016

Accurate design of large icosahedral protein nanocages pushes bioengineering boundaries: Scientists used computational methods to build ten large, two-component, co-assembling icosahedral protein complexes the size of small virus coats July 25th, 2016

New remote-controlled microrobots for medical operations July 23rd, 2016

Nanoparticle versus cancer: Scientists have created nanoparticles which cure cancer harmlessly July 22nd, 2016

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







Car Brands
Buy website traffic