Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Artificial Nanopores Take Analyte Pulse

27.07.2007
Reliable nanopores by two-step etching

Resistive pulse sensing represents a very attractive method for identifying and quantifying biomedical species such as drugs, DNA, proteins, and viruses in solution. This method involves measuring changes in the ionic current across a membrane containing a single nanometer-sized pore that separates two electrolyte solutions. As the biological analytes make their way through the pore, they induce transient downward current pulses in the ionic current by transiently blocking the nanopore. The frequency, duration, and magnitude of the current pulse contain telltale information that aids the identification and quantification of the analyte. A biological nanopore, á-hemolysin, supported by a lipid bilayer membrane, works well in the detection of various analytes.

However, a major impediment to this system is its lack of mechanical robustness. Indeed, these biological membranes tend to rupture within a few hours, thus precluding their application in practical sensing devices. Now a team of researchers at the University of Florida have come up with a major breakthrough that will aid the reproducible fabrication of robust synthetic single-nanopore membranes.

The nanopores are prepared by a track-etching method. In this approach, a high-energy particle is passed through a synthetic polymer membrane to create a damage track, which is then chemically etched to convert the track to a pore. A major challenge has been ensuring control and reproducibility of the diameter of the resulting pore. Charles R. Martin and his colleagues have developed a two-step etching method to reproducibly fabricate conical pores in polymer membranes with predictive control of the diameters of the pore openings. The conical pores have two openings on opposite faces: a large-diameter base and a small-diameter tip. Much of the sensing action occurs at the tip, since the bioanalytes block the tip while moving across the membrane. It is thus imperative to control the size of this tip opening.

... more about:
»Analyte »Ion »conical »diameter »etching »nanopore »opening

The researchers use the first etch step to define the base and the tip of the conical pores in the membrane. Subsequently, they use a second etching step, while continuously monitoring the ion current, and stop the etching process when the ion current across the membrane reaches a certain value, corresponding to a well-defined tip diameter. This method allows the predictive and reliable fabrication of conical pores with tip openings varying from 10 to 60 nm, which is in the right regime for detecting biological analytes. Martin and his colleagues have illustrated the dramatic potential of these membranes by detecting a protein analyte, bovine serum albumin, using nanopore sensors with two different tip diameters. The protein more effectively blocks the pores of a nanopore sensor with a tip diameter of 17 nm as compared to a sensor with 27-nm tips, and this is reflected in the current pulse data. “This method may allow us to take artificial nanopore sensors from the bench top to the practical prototype-device development stage”, said Martin, emphasizing that the reproducible preparation of artificial nanopores is critical for the development of resistive-pulse sensors.

Author: Charles R. Martin, University of Florida (USA), http://www.chem.ufl.edu/~crmartin/

Title: A Method for Reproducibly Preparing Synthetic

About Small: Micro and Nano: No small Matter. Science at the nano- and microscale is currently receiving enormous wordwide interest. Published by Wiley-VCH, Small provides the very best forum for experimental and theoretical studies of fundamental and applied interdisciplinary research at these dimensions. Read an attractive mix of peer-reviewed Communications, Reviews, Concepts, Highlights, Essays, and Full Papers.

Small | Small
Further information:
http://www.chem.ufl.edu/~crmartin/
http://pressroom.small-journal.com

Further reports about: Analyte Ion conical diameter etching nanopore opening

More articles from Life Sciences:

nachricht At last, butterflies get a bigger, better evolutionary tree
16.02.2018 | Florida Museum of Natural History

nachricht New treatment strategies for chronic kidney disease from the animal kingdom
16.02.2018 | Veterinärmedizinische Universität Wien

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

Im Focus: Interference as a new method for cooling quantum devices

Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters

Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...

Im Focus: Autonomous 3D scanner supports individual manufacturing processes

Let’s say the armrest is broken in your vintage car. As things stand, you would need a lot of luck and persistence to find the right spare part. But in the world of Industrie 4.0 and production with batch sizes of one, you can simply scan the armrest and print it out. This is made possible by the first ever 3D scanner capable of working autonomously and in real time. The autonomous scanning system will be on display at the Hannover Messe Preview on February 6 and at the Hannover Messe proper from April 23 to 27, 2018 (Hall 6, Booth A30).

Part of the charm of vintage cars is that they stopped making them long ago, so it is special when you do see one out on the roads. If something breaks or...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Fingerprints of quantum entanglement

16.02.2018 | Information Technology

'Living bandages': NUST MISIS scientists develop biocompatible anti-burn nanofibers

16.02.2018 | Health and Medicine

Hubble sees Neptune's mysterious shrinking storm

16.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>