Skip navigation

Monthly Archives: January 2010


As resources in the world dwindle and devices solving many world problems become more sophisticated, research reducing the size of components to very small parts, nanotechnology, can provide more efficient ways to use resources and efficiently solve problems. One problem aspects of nanotechnology have already solved is the challenge of detecting soybean rust spores. In 2004, these spores, Phakopsora pachyrhizi, were introduced into the continental United States. They lead to a serious foliar disease that only affects soybeans, and they can wipe out complete soybean fields. While they have had only a minute effect on U. S. soybean agriculture, they have been devastating the soybean agriculture of South America. The soybean rust fungus makes many spores and spreads its population by wind transportation, where afternoon drafts of hot air currents send them to the upper atmosphere and they meld with rainwater to be sent back down after a period of movement. Ever since these spores became a larger problem, farmers needed a way of quickly sensing spores entering their farmland in order to know when to apply pesticide and when not to (Wikipedia).

Brian Cunningham of the University of Illinois created a prototype photonic crystal biosensor in 2000. It uses a crystal spectrometer to measure the change in frequency when laser beams from a distributive feedback (DFB) laser make contact with soybean rust spores. A spectrometer is a measuring tool that tells the user what frequency of light is entering a peephole by separating the light through a crystal prism. In order to block out any radiation that would flood the surface of the crystals, there are nanostructured grating layers that acts as a reflectors for all radiation at the original frequency (any radiation that didn’t come into contact with soybean rust particles), while letting through any altered beams. Through biochemical binding, the sensor measured the change in the radiation. Thus the biosensors could detect spores, but they would need careful alignment to keep the beam fixed on the spectrometer and the spectrometer would have to be of a high resolution to accurately pick up on the spores (Cummins).

Therefore Cunningham devised a better way to detect spores. Using a series of DFB lasers that are only deflected by the soybean rust spore, he used nanophotonic discs instead of the spectrometer to receive the deflected beams. These discs are about two nanometers thick, two millimeters wide, and there are 96 discs in total. The nanophotonic discs are created using cheap nanoreplica molding making the receiving foil very thin over a large surface area. The laser is powered with an optical pump with no need for precise angular alignment, for the nanophotonic discs can measure any changes in the wavelength of the laser which are caused by the soybean rust spores (Ahmed).

The use of nanophotonic discs to measure wave changes can be more accurate for many small discs can fit in a small area and measure the same shift in radiation, while a relatively large spectrometer couldn’t. That way, if there is a false positive or false negative reading for the presence of soybean rust, there are also complementary readings for comparison. Also, the nanophotonic discs are thin and spread out from each other, so the air may be sampled to a higher degree than a single assay that is fixed to one large spectrometer. A more important advantage is that the cost of producing and replacing nanophotonic plates is much less than that of large spectrometers. Since the discs are two nanometers thick, it takes negligible amounts of material to create them and the techniques for making layers of nanosheets have become more efficient through new molding techniques. In order for farmers to use any scanner, they must see some advantage to using it. Simply stated, a farmer won’t spend $1,000 a year to save $50. Thus the Photonic Crystal Biosensor is not well suited for this economic environment, while the DFB laser biosensor is smaller, simpler, and much more accurate (Sun).

As more time passes, there are more and more ways to integrate nanotechnology into devices to make them cheaper and more effective. The FDA has been highly involved in funding more research for nanophotonic devises, while companies like Molecular Manufacturing Shortcut fund nanotechnology as a way to develop future basis for extraterrestrial habitation (Shortcut). Many new technologies are just above the horizon, and nanotechnology is helping humans bridge the link between now and the future.


Bibliography

Wikipedia contributors, “Soybean rust,” Wikipedia, The Free Encyclopedia,

http://en.wikipedia.org/w/index.php?title=Soybean_rust&oldid=269383855

(accessed January 12, 2010).

This article describes soybean rust spores.

Cummins, Marilyn. “Deadly Katrina to move soybean rust spores to the MW and NE U.S.,
S. Ontario and Quebec.” Stop soybean rust.

This article references how the Photonic Crystal Biosenser works.

“Molecular Manufacturing Shortcut Group.” Molecular Manufacturing Shortcut
Group. http://www.islandone.org/MMSG/ (accessed February 1, 2010).

I used this source to point out an alternate application of
nanotechnology.

Ahmed, Irfan. Interview by author, Micro and Nanotechnology Laboratory. January 10, 2010.
Professor Irfan was the professor who I met with for an hour and talked to about
nanotechnology involving detecting soybean rust spores.

Sun, Chang Q. “Size dependence of nanostructures: Impact of bond.” Science Direct
http://www3.ntu.edu.sg/home/ECQSun/rtf/PSSC-size.pdf (accessed January 11, 2010).

I read through this article and found a description of the fortes of nanophotonic
crystal biosensors and DFB laser biosensors.


Many Haitians have gone without food or water since the 7.0 magnitude earth quake this Tuesday January 14th. In Port-au-Prince, Haiti’s Capital, people are living on the side walks in total shock. With such devastation, it’s no surprise crime is on the rise.

Currently, the Red Cross estimates 45000-50000 people have died already, while the Telegraph estimates that the death toll may exceed 100000.

Bodies were literally thrown into the streets.

But the question that comes to my mind, is why aren’t countries sending millions of workers to aid Haiti; why aren’t the contributions given by hundreds of millions of people world-wide not significantly affecting Haiti?

The reason, a lot of the help that was supposed to be in Haiti had difficulty getting into Haiti, since the main dock in Port-au-Prince was closed after the earth quake.

Ships stocked with aid couldn’t get in. Only now that the US has gain firmer control of the Port-au-Prince airport, have more supplies started coming in.

But by sending helicopters and taking control of the Airport, many countries are accusing the US of annexing the airport, (how absurd is that?) and protesters in France and Brazil are indirectly hindering the aid effort.

Unfortunately, a minority of rebellious Haitians are spreading rumors that the food that the UN is handing out is poisoned and rotten. That means that a lot of food is wasted, so a few selfish individuals can take the food that others threw away.

What the world should learn from this crisis, and previous crises is that every country needs to have a back-up emergency plan for what it should do in cases of natural disasters. Such a protocol can be reached by a an organization like the UN, but it takes concerned citizen from all countrys to make such a plan a reality.