http://www.natureasia.com/en/nindia/article/10.1038/nindia.2014.140

 Nature (2014)  

doi:10.1038/nindia.2014.140 Published online 27 October 2014 

Research highlight

Magnetic nanoemulsions make glucose sensor

Researchers have fabricated a sensitive, enzyme-free sensor that can rapidly measure low concentrations of glucose1. They made the sensor using surfactant-containing magnetic nanoemulsions. It is potentially useful for measuring glucose levels in diabetic patients, foods and biochemical samples.

References

1. Mahendran, V. & J.Philip, Non-enzymatic glucose detection using magnetic nanoemulsions. Appl. Phys. Lett. 105, 123110 (2014)

http://nanotechweb.org/cws/article/tech/58705

Nanotechweb (2014)

TECHNOLOGY UPDATE

Sep 26, 2014

Magnetic nanoemulsion measures blood glucose

A new type of glucose sensor that works using a magnetically polarizable nanoemulsion could help change the way blood sugar is measured. The new device does not rely on glucose oxidase enzymes, unlike conventional glucometers, but instead simply changes colour when it comes into contact with glucose.

A team of researchers, led by John Philip at the Indira Gandhi Centre for Atomic Research   in India, made the new sensor using a magnetically polarizable oil-in-water nanoemulsion of droplets that have a radius of around 100 nm. They made the emulsion by mixing together ferrimagnetic nanoparticles of iron oxide (around 10 nm across) with oil, a surfactant and water.

About the author

Belle Dumé is contributing editor atnanotechweb.org

http://www.nature.com/nindia/2013/130312/full/nindia.2013.35.html 

doi:10.1038/nindia.2013.35; Published online 12 March 2013 

Research highlight 

Optical toxic-gas detector 

Researchers have invented a novel, fast and ultrasensitive magnetic-nanofluid-based optical sensor that changes colour on exposure to extremely low concentrations of ammonia 1. The sensor will be useful in detecting minute traces of ammonia in industrial and environmental samples.

References

1.    Mahendran, V. et al. An optical technique for fast and ultrasensitive detection of ammonia using magnetic nanofluids. Appl. Phys. Lett. 102, 063107 (2013)

http://nanotechweb.org/cws/article/tech/52633

A community website from IOP Publishing

Nanotechweb (2013)

TECHNOLOGY UPDATE   Mar 7, 2013

Colour changing nanofluid senses ammonia

Researchers at the Indira Gandhi Centre for Atomic Research (IGCAR) in India have made a new type of optical sensor from magnetically polarizable nanofluids and have used the device to detect tiny amounts of ammonia in solution. The sensor, which quickly changes colour in the presence of the analyte, could come in useful for many practical applications, such as monitoring pollution levels in rivers around industrial plants.

The team, which has published its results in Applied Physics Letters, now hopes to further improve the sensitivity of its sensor and use it to detect other toxic analytes. Another important goal is to make the sensor in a reusable thin film form, adds Philip.

About the author

Belle Dumé is contributing editor at nanotechweb.org 

http://www.thehindu.com/sci-tech/article3025222.ece

IGCAR develops sensors to inspect defects in materials

R. PRASAD

Special Arrangement Test specimens with two circular defects – one big and one small (right) and a rectangular and a circular defect (left) imaged using nanofluid optical sensor developed by Dr. John Philip, IGCAR, Kalapakkam

Defective regions produce magnetic resistance, which in turn leads to leakage of magnetic flux

Detecting and imaging structural defects like cracks, holes etc, present in components made of ferromagnetic materials like pipelines, railway tracks and tubes has now become easy with optical sensors. These sensors were developed by Dr. John Philip and his team at the Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam near Chennai. The results of their work were published recently in the Applied Physics Letters journal.

http://www.nature.com/nindia/2012/120215/full/nindia.2012.21.html

doi:10.1038/nindia.2012.21; Published online 15 February 2012

Research highlight 

NATURE (2012)    

Sensor detects cracks in magnetic matter

Researchers have developed a new kind of optical sensor from an emulsion of magnetic nanofluid containing droplets of iron oxide nanoparticles1. The sensor could be used to image defects such as cracks, corrosion and erosion buried in rail tracks, pipelines and tubes.

References

Mahendran, V. & John Philip, Nanofluid based optical sensor for rapid visual inspection of defects in ferromagnetic materials. Appl. Phys. Lett. 100, 073104 (2012)

http://nanotechweb.org/cws/article/tech/48783

IOP A community website from IOP publishing, UK

Nanotechweb (2012)

TECHNOLOGY UPDATE

Feb 27, 2012

Nanofluid sensor images defect

A new optical sensor that can image internal defects in ferromagnetic materials has been invented by researchers in India. The photonic eye, as it has been dubbed, is based on a magnetically polarizable nano-emulsion that changes colour when it comes into contact with a defective region in a sample. The device might be used to monitor structures such as rail tracks and pipelines.

The sensor will be able to locate defects and discontinuities such as fatigue, cracks, corrosion pits, metallic inclusions and abrasion in ferromagnetic components and structures, says team leader John Philip of the Indira Gandhi Centre for Atomic Research (IGCAR) in Tamilnada. It might also be used to inspect magnetic materials used in the aircraft industry, such as those used to make turbines, for example.

The current work is detailed in Applied Physics Letters.

About the author

Belle Dumé is contributing editor at nanotechweb.org

http://www.nature.com/nindia/2011/110926/full/nindia.2011.136.html

doi:10.1038/nindia.2011.136; Published online 26 September 2011

Research highlight 

NATURE (2011)  

Nanofluids as power savers

Researchers have produced a new viscous nanofluid containing magnetic nanoparticles that conducts heat efficiently when under an intense magnetic field1. This magnetic nanofluid could be useful as a super-coolant or for damping unwanted vibrations in optoelectronic devices.

"This magnetic nanofluid could be used to design multifunctional smart materials for cooling-cum-damping applications," says lead researcher John Philip. Such fluids can also be used to improve the heat transfer of solar collectors used to harness solar energy, he adds.

References

Shima, P. D. & J.Philip Tuning of thermal conductivity and rheology of nanofluids using an external stimulus. J. Phys. Chem. C doi:10.1021/jp204827q (2011) 

http://nanotechweb.org/cws/article/tech/47381

NANOTECHWEB (2011)    

Technology update  

Sep 30, 2011

"Intelligent" nanofluids could cool computer chips

Certain nanofluids can be made to conduct heat extremely well when a magnetic field is applied to them, says a duo of researchers at the Indira Gandhi Centre for Atomic Research in Tamilnadi, India. The phenomenon may be used to cool down miniature devices like micro- and nano-electromechanical systems, and computer chips. 

"Nanofluids could be ideal coolants for future electronic devices but for such applications, the fluids need to have large thermal conductivities," explained team leader John Philip. "This is why we need to develop novel nanofluids."  The materials studied by the researchers are a colloidal suspension of single-domain superparamagnetic Fe3O4 nanoparticles between 3 and 10 nm in size that are magnetically polarizable – that is, they respond to a weak magnetic field.

The current work is reported in The Journal of Physical Chemistry C.

About the author

Belle Dumé is contributing editor at nanotechweb.org

https://www.nature.com/articles/nnano.2008.38 

Published online: 8 February 2008 | doi:10.1038/nnano.2008.38

Nature Nanotechnology (2008) 

Magnetic nanofluids: Chain reaction

Adarsh Sandhu

Abstract

Fluids containing magnetic nanoparticles can display potentially useful thermal properties

Introduction

Colloid suspensions containing magnetic nanoparticles are known to exhibit higher thermal conductivities than liquids with larger particles or no particles at all. The enhanced thermal conductivity of these magnetic nanofluids could have applications in controlling the flow of heat in various devices if it can be controlled in a reversible manner.

Now, John Philip and colleagues1 of the Indira Gandhi Center for Atomic Research have demonstrated such control over a suspension of hexadecane containing 6.7-nm superparamagnetic particles. When a magnetic field of 101 Gauss is applied to a nanofluid that contains 4.5% nanoparticles by volume, the thermal conductivity was enhanced by 216%. The magnetic field caused the nanoparticles to form chains in the direction of the magnetic field, with the chains falling apart when the field was switched off.

Evidence that this mechanism is indeed responsible for the enhanced thermal conductivity was provided by measurements showing that the efficiency of heat flow along the chains increased in the presence of the magnetic field.

REFERENCE

1.    Philip, J., Shima, P. D. & Raj, B. Nanofluid with tunable thermal properties. Appl. Phys. Lett. 92, 043108 (2008).   

Nanotechweb (2008)

TECHNOLOGY UPDATE

Apr 4, 2008

Nanofluid could cool tiny electronic devices  

Researchers in India have shown that the thermal properties of a magnetic nanofluid can be tuned by applying a magnetic field. The effect comes thanks to the magnetic particles lining up in chains when the field is applied. The nanofluid, which is made from a colloidal suspension of magnetite nanoparticles, could find use in a variety of technology applications, including "smart" cooling devices.

Philip and co-workers developed a stable colloidal suspension of Fe3O4 nanoparticles, with an average diameter of 6.7 nm. "The observed reversibly tunable thermal property of our nanofluid may find many technological applications in nanoelectromechanical and microelectromechanical-based devices," Raj told nanotechweb.org. "For example, depending on the cooling requirement, the magnetic field can be precisely programmed to obtain the desired level of thermal conductivity enhancement or cooling," added Philip.

The work was published in Applied Physics Letters.

About the author

Belle Dumé is contributing editor at nanotechweb.org