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Carbon nanotube based biosensors

Identification

Key words Carbon nanotube, biosensors, conductivity, food pathogen, antigen, antibody, protein, enzyme, DNA, glucose, immunosensors
Latest version 2012/03/15
Completed by UTCN

How does it work?

Primary objective Detection of food pathogens.
Working principle The use of nanoscale materials (e.g. carbon nanotubes - CNTs) in biosensors has opened the gate for new opportunities. CNTs are hexagonal networks of carbon atoms of approximately 1 nm diameter and 1 to 100 microns of length that have either metallic or semiconducting properties.They can be described as a layer of graphite rolled-up into a cylinder and may be composed of single shell–single wall nanotubes (SWNTs), or of several shells—multi-wall nanotubes (MWNTs)[3]. Carbon nanotubes possess many unique properties (size, elasticity, electrically conductive and they can be modified at their ends with specific chemical or biological groups for high resolution functional imaging) which make them ideal for different applications. [1]

One application of CNT biosensors is the detection of extremely low concentrations of the typhus-inducing Salmonella typhi (quantitative measurements are possible down to a concentration of about 1.000 salmonella per milliliter). This method is based on electrochemical measurements by means of carbon nanotubes equipped with aptamers as bacteria-specific binding sites. If bacteria binds to the aptamers, a change in electrical voltage is detected. Other applications such as detection of proteins, antibody–antigen assays, DNA hybridization, and enzymatic reactions involving glucose are possible. [6]

Images
Additional effects Purification pretreatment of CNTs (dry ashing coupled with acid extraction, wet digestion, and a combination of dry ashing with acid digestion) is imposed in order to avoid metallic impurities, and/or to improve electron transfer properties and/or to permit further functionalities. [5][7]
Important process parameters
  • process temperature
  • conductivity of the biosensor
  • incubation time
  • incubation temperature
  • sensitivity
  • length to diameter radio of the nanotube
Important product parameters

What can it be used for?

Products Potential use for any common liquid or solid food matrix.
Operations Stabilizing
Solutions for short comings Faster detection of food borne pathogens compared to other biosensors (optical biosensors such as integrating waveguide biosensor, photodiode based detection or electrochemical detection systems).

What can it NOT be used for?

Products
Operations CNTs cannot be used at high temperatures. Exposure to sunlight, heat, or extreme conditions may also alter the environmental behaviour of the biosensor. Irradiation by ultraviolet light may cause particle dissolution or release of the CNT.
Other limitations Expensive production, challenges at fabrication level (purification, dispersion, alignment and adhesion of nanotubes and the limitations in interfacial load transfer), duration from proof of concept in the laboratory to the commercial market. [3][8]
Risks or hazards Some physical characteristics of CNTs, like their length to diameter ratio, low solubility in aqueous media, propensity to agglomerate, being light and able to become airborn, among others, suggest that they may be toxic. Although data are still fragmentary and subject to criticisms, e.g. because of the non-physiological mode of administration used, the results indicate that if CNTs reach the lungs they can exert serious toxicity, manifested in experimental animals as inflammatory and fibrotic reactions. These reports represent a cause of concern for human health and indicate that strict preventive and protective measures should be taken to limit inhalation exposure to CNTs in occupational settings. [1]

Implementation

Maturity Mainly used at lab-scale but proven to be reliable as commercial application.
Modularity /Implementation CNTs can be used along the production line for e.g. pathogen detection.
Consumer aspects No related information was found.
Legal aspects Please check local legislation.
Environmental aspects Nanoparticles can be absorbed in the soil because of their ability to form micro-structures. When dispersed in water, the water may form a sheath around each nanoparticle allowing it to travel through the soil with less absorption. The particles could possibly move up the food chain by being ingested by earthworms.

The biodegrading ability of nanoparticles has been shown to be very substance, surface, and size specific, and estimated between 8 weeks to 2 years.

Further Information

Institutes KU Leuven MeBioS, PAN OLSZTYN, Trinity College Dublin
Companies ABB
References
  1. Julie Muller, François Huaux, Dominique Lison, Respiratory toxicity of carbon nanotubes: How worried should we be?, Carbon, 2006, Volume 44, Issue 6, p. 1048–1056
  2. Kannan Balasubramanian . Marko Burghard, Biosensors based on carbon nanotubes, Anal Bioanal Chem, 2006, 385: p. 452–468
  3. Niraj Sinha, Jiazhi Ma, and John T. W. Yeow, Carbon Nanotube-Based Sensors, Journal of Nanoscience and Nanotechnology, 2006, Vol.6, p. 573–590
  4. Subramanian Viswanathan, Jerzy Radecki, Nanomaterials in electrochemical biosensors for food analysis – a review, Polish Journal of food and nutrition sciences, 2008, Vol. 58, No. 2, p. 157-164
  5. Xiuli Yue, Zhifei Dai, Chapter 19- Carbon Nanotube-Based Cholinesterase Biosensors for the Detection of Pesticides, ‘New Perspectives in Biosensors Technology and Applications’, ISBN 978-953-307-448-1, Edited by: Pier Andrea Serra, Publisher: InTech, July 2011.
  6. Xueqing Zhang, Qin Guo and Daxiang Cui, Recent Advances in Nanotechnology Applied to Biosensors, Sensors, 2009, Issue 9, p. 1033-1053
  7. Cuicui Ge, Fang Lao, Wei Li, Yufeng Li, Chunying Chen, Yang Qiu, Xueying Mao, Bai Li, Zhifang Chai and Yuliang Zhao, Quantitative Analysis of Metal Impurities in Carbon Nanotubes: Efficacy of Different Pretreatment Protocols for ICPMS Spectroscopy, Anal. Chem., 2008, 80 (24), pp 9426–9434
  8. Kausala Mylvaganam and Liangchi C. Zhang, Fabrication and Application of Polymer Composites Comprising Carbon Nanotubes, Recent Patents on Nanotechnology 2007, 1, 59-65

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  • conductivity of the biosensor
  • incubation time
  • incubation temperature
  • sensitivity
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  • conductivity of the biosensor
  • incubation time
  • incubation temperature
  • sensitivity
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Created by RusVUTCN on 15 March 2012, at 09:21