Nanotechnology Now

Our NanoNews Digest Sponsors



Heifer International

Wikipedia Affiliate Button


android tablet pc

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

A novel method for identifying the body’s ‘noisiest’ networks November 19th, 2014

Researchers discern the shapes of high-order Brownian motions November 17th, 2014

VDMA Electronics Production Equipment: Growth track for 2014 and 2015 confirmed: Business climate survey shows robust industry sector November 14th, 2014

Open Materials Development Will Be Key for HP's Success in 3D Printing: HP can make a big splash in 3D printing, but it needs to shore up technology claims and avoid the temptation of the razor/razor blade business model in order to flourish November 11th, 2014

Sensors

Promising new method for rapidly screening cancer drugs: UMass Amherst researchers invent fast, accurate new nanoparticle-based sensor system December 15th, 2014

Graphene Applied in Production of Recyclable Electrodes December 13th, 2014

Detecting gases wirelessly and cheaply: New sensor can transmit information on hazardous chemicals or food spoilage to a smartphone December 8th, 2014

Nanosensor to Detect Naproxen Drug Produced in Iran December 6th, 2014

Nanoelectronics

Stacking two-dimensional materials may lower cost of semiconductor devices December 11th, 2014

Defects are perfect in laser-induced graphene: Rice University lab discovers simple way to make material for energy storage, electronics December 10th, 2014

Nanoscale resistors for quantum devices: The electrical characteristics of new thin-film chromium oxide resistors that can be tuned by controlling the oxygen content detailed in the 'Journal of Applied Physics' December 9th, 2014

'Giant' charge density disturbances discovered in nanomaterials: Juelich researchers amplify Friedel oscillations in thin metallic films November 26th, 2014

Materials/Metamaterials

ORNL microscopy pencils patterns in polymers at the nanoscale December 17th, 2014

Pb islands in a sea of graphene magnetise the material of the future December 16th, 2014

Graphene Applied in Production of Recyclable Electrodes December 13th, 2014

A golden thread through the labyrinth of nanomaterials December 12th, 2014

Announcements

Switching to spintronics: Berkeley Lab reports on electric field switching of ferromagnetism at room temp December 17th, 2014

ORNL microscopy pencils patterns in polymers at the nanoscale December 17th, 2014

Unraveling the light of fireflies December 17th, 2014

First Home-Made Edible Herbal Nanodrug Presented to Pharmacies across Iran December 17th, 2014

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







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE