Corporate Banner
Satellite Banner
Automation & Microfluidics
Scientific Community
Become a Member | Sign in
Home>News>This Article

Novel Chip-based Platform Could Simplify Measurements of Single Molecules

Published: Wednesday, August 13, 2014
Last Updated: Monday, August 18, 2014
Bookmark and Share
A nanopore-gated optofluidic chip combines electrical and optical measurements of single molecules onto a single platform.

Researchers at UC Santa Cruz have developed a new approach for studying single molecules and nanoparticles by combining electrical and optical measurements on an integrated chip-based platform. In a paper published July 9 in Nano Letters, the researchers reported using the device to distinguish viruses from similarly-sized nanoparticles with 100 percent fidelity.

Combining electrical and optical measurements on a single chip provides more information than either technique alone, said corresponding author Holger Schmidt, the Kapany Professor of Optoelectronics in the Baskin School of Engineering and director of the W. M. Keck Center for Nanoscale Optofluidics at UC Santa Cruz. Graduate student Shuo Liu is first author of the paper.

The new chip builds on previous work by Schmidt's lab and his collaborators at Brigham Young University to develop optofluidic chip technology for optical analysis of single molecules as they pass through a tiny fluid-filled channel on the chip. The new device incorporates a nanopore that serves two functions: it acts as a "smart gate" to control the delivery of individual molecules or nanoparticles into the channel for optical analysis; and it allows electrical measurements as a particle passes through the nanopore.

"The nanopore delivers a single molecule into the fluidic channel, where it is then available for optical measurements. This is a useful research tool for doing single-molecule studies," Schmidt said.

Biological nanopores, a technology developed by coauthor David Deamer and others at UC Santa Cruz, can be used to analyze a DNA strand as it passes through a tiny pore embedded in a membrane. Researchers apply voltage across the membrane, which pulls the negatively charged DNA through the pore. Current fluctuations as the DNA moves through the pore provide electrical signals that can be decoded to determine the genetic sequence of the strand.

With the new device, researchers are able to gather electrical measurements on a nanoparticle as it moves through a pore in a solid membrane, and then measure the optical signals when the particle encounters a beam of light in the channel. By correlating the strength of the current decrease as a particle moves through the pore, the intensity of the optical signal, and the time of each measurement, the researchers are able to discriminate among particles with different sizes and optical properties and to determine the flow speed of particles through the channel.

The chip can also be used to differentiate particles of similar size but different composition. In one experiment, the researchers combined influenza viruses with nanobeads of a similar diameter and placed the mixture above the nanopore. The virus was labeled with a red fluorescent tag and the beads were labeled with a blue tag. The researchers correlated the electrical signal with the fluorescent wavelength and the time of each measurement. They found that the blue nanobeads traveled faster through the channel than red influenza virus, perhaps because of a difference in surface charge or mass. Besides identifying pathogens in a mixture, the researchers can also count the number of virus particles.

"This could be used as an analytical device to do reliable counts of virus particles in a sample," Schmidt said.

Currently, Schmidt's group is working on methods to add optical trapping to the device. This would allow a molecule in the channel to be held in one place, investigated, and released, with the potential to analyze hundreds of molecules in an hour. "Having this all on one chip would make single-molecule measurements much easier and more convenient," Schmidt said.

In addition to Liu and Schmidt, the coauthors include UCSC graduate student Joshua Parks, and Yue Zhao and Aaron Hawkins at Brigham Young University. This work was supported by the Keck Center for Nanoscale Optofluidics and grants from the National Science Foundation and National Institutes of Health.

Further Information
Access to this exclusive content is for Technology Networks Premium members only.

Join Technology Networks Premium for free access to:

  • Exclusive articles
  • Presentations from international conferences
  • Over 2,600+ scientific posters on ePosters
  • More than 3,800+ scientific videos on LabTube
  • 35 community eNewsletters

Sign In

Forgotten your details? Click Here
If you are not a member you can join here

*Please note: By logging into you agree to accept the use of cookies. To find out more about the cookies we use and how to delete them, see our privacy policy.

Scientific News
Chip-Based Technology Enables Reliable Direct Detection of Ebola Virus
Hybrid device integrates a microfluidic chip for sample preparation and an optofluidic chip for optical detection of individual molecules of viral RNA.
Stem Cell Research Hints at Evolution of Human Brain
Researchers at UC San Francisco have succeeded in mapping the genetic signature of a unique group of stem cells in the human brain that seem to generate most of the neurons in our massive cerebral cortex.
Developing a Breathalyzer-Type Low Blood Sugar Warning Device For Diabetes
A multidisciplinary team of researchers at Indiana University-Purdue University Indianapolis has been awarded a $738,000 National Science Foundation grant to develop a breathalyzer-type device to detect the onset of hypoglycemia, or low blood sugar episodes, in people with diabetes.
Smartphone App to Monitor Serious Blood Disorder
A researcher from Florida Atlantic University has come up with a unique way to monitor sickle cell disease -- a serious blood disorder -- using a smart phone.
Preventing Crystallization to Improve Drug Efficiency
Esther Amstad and an international team of researchers have developed a method to increase the solubility of poorly soluble substances, such as many of the newly developed drugs.
‘Lab-on-a-Chip’ Technology Cuts Costs of Lab Tests
With ability to analyze minuscule amounts of fluid, Rutgers breakthrough could also promote central nervous system and joint research.
The Changing Tides of the In Vitro Diagnostics Market
With the increasing focus in personalized medicine, diagnostics plays a crucial role in patient monitoring.
Capturing Cell Growth in 3-D
Spinout’s microfluidics device better models how cancer and other cells interact in the body.
Device May Detect Urinary Tract Infections Faster
A Lab-on-a-Disc platform developed by a German and Irish team of researchers dramatically cut the time to detect bacterial species that cause urinary tract infections -- a major cause of sepsis.
Automation Abound at AACC in Atlanta
Discover the latest breakthroughs, trends and products from the AACC Annual Meeting & Clinical Lab Expo.
Scroll Up
Scroll Down
Skyscraper Banner

Skyscraper Banner
Go to LabTube
Go to eposters
Access to the latest scientific news
Exclusive articles
Upload and share your posters on ePosters
Latest presentations and webinars
View a library of 1,800+ scientific and medical posters
2,600+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
3,800+ scientific videos