Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Gilded Bacteria

Abstract:
Humidity sensor: hybrid nanoelectronics made from living bacteria and gold nanoparticles

Gilded Bacteria

October 07, 2005

Living organisms as an integral part of electronic components? What may look like science fiction at first glance is actually a serious approach to the nanoelectronics of tomorrow. Living organisms could provide the required nanostructures. Researchers at the University of Nebraska (Lincoln, USA) have now shown that bacteria coated with gold nanoparticles can function as a humidity sensor.

The properties of metallic nanoparticles differ radically from those of larger particles and are of great interest for nanoelectronics. In order to use nanoparticles, they must be placed on a suitable support, a “nanoscaffold.” “Biological structures have proven to be promising supports,” explains Ravi Saraf, “especially when their responses to stimuli can be integrated.”

Saraf and his co-worker, Vikas Berry, produced a chip covered with extremely fine gold electrodes and applied a suspension of Bacillus cereus. On such surfaces, these long bacteria basically lie down to form bridges between the pairs of electrodes. Then the nanoparticles come in: the researchers dipped their chip into a solution of gold nanoparticles coated with polylysine, a synthetic protein. The tiny gold particles are strongly attracted to the bacterial surface, which contains long, brushlike, highly mobile chain molecules that are negatively charged. Like tentacles, these surround the gold particles - positively charged by the polylysine - and hold them tight. At the end of this process, the bacteria are coated with a thin layer of gold nanoparticles - and are still alive.

The researchers apply a voltage of 10 V across the electrode pairs and measure the current across the bacterial bridges to complete the bioelectronic humidity sensor. If the humidity is increased from about 0 to 20%, the current decerases by a factor of 40. Why does this chip react so sensitively to changes in humidity? Moisture causes the bacterial membrane to swell, which increases the distance between the individual gold particles attached to it by about 0.2 nm. This is not much, but it is enough to hinder electron transport between the particles. Unlike a “normal” macroscopic gold layer, in which the electrons can “flow” unhindered, here they must “jump” from one particle to the next.

“Our humidity sensor demonstrates the vast potential that lies in hybrid structures containing microorganisms and nanoparticles,” says Saraf.

####


Author: Ravi F. Saraf, University of Nebraska, Lincoln (USA), link

Title: Self-Assembly of Nanoparticles on Live Bacterium: An Avenue to Fabricate Electronic Devices

Angewandte Chemie International Edition 2005, 44, 6668, doi: 10.1002/anie.200501711

Contact:
Editorial office: angewandte@wiley-vch.de

David Greenberg (US)
dgreenbe@wiley.com

Julia Lampam (UK)
jlampam@wiley.co.uk

Copyright © Angewandte Chemie

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

Possible Futures

Searching for errors in the quantum world September 21st, 2018

Viral RNA sensing: Optical detection of picomolar concentrations of RNA using switches in plasmonic chirality September 21st, 2018

UT engineers develop first method for controlling nanomotors: Breakthrough for nanotechnology as UT engineers develop first method for switching the mechanical motion of nanomotors September 21st, 2018

Leti Announces EU Project to Develop Powerful, Inexpensive Sensors with Photonic Integrated Circuits: REDFINCH Members Initially Targeting Applications for Gas Detection and Analysis For Refineries & Petrochemical Industry and Protein Analysis for Dairy Industry September 19th, 2018

Sensors

UT engineers develop first method for controlling nanomotors: Breakthrough for nanotechnology as UT engineers develop first method for switching the mechanical motion of nanomotors September 21st, 2018

Leti Announces EU Project to Develop Powerful, Inexpensive Sensors with Photonic Integrated Circuits: REDFINCH Members Initially Targeting Applications for Gas Detection and Analysis For Refineries & Petrochemical Industry and Protein Analysis for Dairy Industry September 19th, 2018

Rice U. lab probes molecular limit of plasmonics: Optical effect detailed in organic molecules with fewer than 50 atoms September 5th, 2018

Measuring the nanoworld September 4th, 2018

Nanoelectronics

How a tetrahedral substance can be more symmetrical than a spherical atom: A new type of symmetry September 14th, 2018

Laser sintering optimized for printed electronics: New study sheds (laser) light on the best means of laying down thin-film circuitry September 13th, 2018

September 5th, 2018

Rice U. lab probes molecular limit of plasmonics: Optical effect detailed in organic molecules with fewer than 50 atoms September 5th, 2018

Materials/Metamaterials

How a tetrahedral substance can be more symmetrical than a spherical atom: A new type of symmetry September 14th, 2018

Peering into private life of atomic clusters -- using the world's tiniest test tubes September 6th, 2018

Cannibalistic materials feed on themselves to grow new nanostructures September 1st, 2018

Environmentally friendly photoluminescent nanoparticles for more vivid display colors: Osaka University-led researchers created a new type of light-emitting nanoparticle that is made of ternary non-toxic semiconductors to help create displays and LED lighting with better colors t August 29th, 2018

Announcements

Searching for errors in the quantum world September 21st, 2018

Viral RNA sensing: Optical detection of picomolar concentrations of RNA using switches in plasmonic chirality September 21st, 2018

UT engineers develop first method for controlling nanomotors: Breakthrough for nanotechnology as UT engineers develop first method for switching the mechanical motion of nanomotors September 21st, 2018

Nanobiotix: Update on Head and Neck Phase I/II Trial with NBTXR3 and Other program data presented at ImmunoRad 2018 September 20th, 2018

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



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project