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A Radical Change in Perspective

Posted on March 17, 2012 | Leave a comment

I apologize in advance for the pun but I feel that this accurately describes the situation (at least for me). As always, this news comes from our good friends at MIT. Dr. JoAnne Stubbe, professor of chemistry and biology wish to remove the “bad rep” associated with free radicals. Before getting into her explanation, free radicals are molecules or atoms that are unstable due to an unpaired electron or unfilled valence shell (the outermost electron shell of an atom). These factors give free radicals the property of being unstable and are able to react readily with several molecules with little predictability. This reactivity means that radicals can cause unwanted reactions such as with DNA and have been suspected by scientists to be a factor in aging for humans and other living beings.

Dr. JoAnne Stubbe presents the 40th Annual James R. Killian Jr. Faculty Achievement Award Lecture. Photo: Dominick Reuter

With this bad publicity on free radicals in the human body, many companies and scientists have promoted in the consumption of antioxidants to react with the free radicals instead of important molecules such as DNA. In our SCIE300 blog, there are also several posts regarding the consumption of a lot of free radicals to improve health.

However, Dr. Stubbe suggests that free radicals are a misunderstood bunch in the eyes of society. She gives the analogy of free radicals to protestors against the Vietnam War. According to her, the protesters to society, the “radicals,” are “highly reactive […] and wreaked havoc on everything they interacted with.” But to her, the “radicals” were merely acting in reaction to their hostile environment, like the riot police with “guns raised, masks on.” To her, the free radicals react with DNA because DNA happen to be in their way and not letting them contribute to good pathways present in many enzymes.

“This is textbook material” – Mary Fuller, Associate Chair, MIT

There is a good reason for this view: Dr. Stubbe’s research on the enzyme Ribonucleotide reductase (RNR). RNR is an enzyme that converts nucleotides into deoxynucleotides which are incorporated into DNA which means the RNR is essential to all living beings. But what does RNR has to do with free radicals? It turns out that according to Dr. Stubbe, the RNR’s require free radicals for the conversion of nucleotides to work with “exquisite specificity.” The reactivity of radicals is used to form chain reactions into an enzymatic mechanism that ultimately form the deoxynucleotides. With this new information, several possibilities are opened up such as cancer treatment since we can possibly stop RNR to stop uncontrolled DNA and cell replication.

With this new information on free radicals, let’s hope to see more articles on radicals that shine them on a more positive light since according to Dr. Stubbe, “Your life is in their hands.”

Source:
–Freeing radicals from their negative connotations.

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Posted in Biological Sciences, Science in the News

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In the future, medicine will be administered wirelessly

Posted on February 27, 2012 | 3 comments

When the term “microchip” is mentioned, many things come into mind such as science fiction stories describing super-small computers or advanced tracking devices. It is probable that “administering medicine” is one of the last things you would think about when you hear “microchip.” But what if this is actually a reality with probable wide usage?

Professors Robert Langer (right) and Michael Cima (left) at the Koch Institute. Photo by: M. Scott Brauer

Professors Robert Langer and Michael Cima of MIT have been conceptualized this idea 15 years ago. The microchips would be implanted into a patient needing a regular dose of a drug and then the programming of the microchip would release consistent doses appropriate for the treatment. After much research with the scientists of MicroCHIPS Inc. the first reports of successful human trials have been released early this month.

“You could literally have a pharmacy on a chip.” – Professor Robert Lange, MIT.

So how does this microchip work? The microchip stores a certain amount of doses of a certain drug that the patient needs (clinical trials on osteoporosis patients included 20 doses in the chip). The chip would then be programmed to release a certain dosage daily into the patients. This programming can be altered or monitored wirelessly from a doctor’s computer. After programming, the chip would be surgically implanted into the patient’s body.

 

This would mean many things for the patient requiring daily doses of essential medicine. First of all, patients will not have to worry about taking their medicine at an allotted time – the chip will do that for them. This is very significant considering living with a drug regimen of daily self-injections can be strenuous for the patient. Second, the correct dosages will be administered by the microchip at the correct times. The doctor can have the chip programmed differently depending on the dosage and dose times depending on the ailment. An example of this is osteoporosis patients receiving teriparatide daily from the chip.

 

But are there any problems with this chip? This method of drug delivery system has shown to be just as good if not better than normal daily injections the patients have to give themselves. In addition to this, the programming of the chip can be altered to release the drugs as a certain dose per day, or a “pulse” or even a consistent release – all customized for the patient’s needs. The researchers at MicroCHIPS Inc. have also refined the chips to store the drugs in an airtight seal inside the chip and the chip itself to be made of materials that do not interfere with the host’s immune system. In the future, Professors Lange and Cima hope to add sensors to the chips so concentrations of chemicals in the patient (such as glucose) and have the chip adapt to the changing background.

 

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Posted in Biological Sciences, Science in the News

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Capturing Light: How Scientists Caught Up to a Photon

Posted on January 30, 2012 | Leave a comment

There are many videos on YouTube on cool slow-motion videos like water balloons exploding or a bullet through an apple. But what if there was a recording method that can record a travelling photon? Well, our good friends at MIT have accomplished exactly this with their new system of recording an image.

YouTube Preview Image

“There’s nothing in this universe that looks fast to this camera” – Andreas Velten, postdoc

Light bouncing off an apple.

Visualizing photons bending around an object. (Source: MIT)

As we know from first year chemistry courses, a photon is a single unit of light like how a metre is a unit of distance. But unlike other types of particles, light shows properties of both a particle and a wave. This means that the photon can carry energy but is also able to radiate around objects and bounce off. Technically, all cameras capture photons – otherwise there wouldn’t be anything in the picture! The difficult thing is to actually capture the movement of a single unit of light before it bounces off anything.

In the end, the question is, how do scientists record something that moves around 300 million metres per second? The answer is technology called ‘streak camera imaging.’ How this works is that there are five hundred light sensors arranged in a line along a streak. This thin line of sensors detects photons bouncing off their surface and translates them as electron signals. The direction of the electrons is perpendicular to the signal. In the end, these hundreds of sensors produce a single slit image as the light travels horizontally. Since the sensors are in a slit, a single run produces a strip of an image – imagine only one line of pixels were lit up at your computer screen right now. The light bean is therefore recorded multiple times with different mirror configurations so that different layers of these strips can be put together to create a coherent movie shown in this post. It is ironic in a sense to see a device so slow in producing a short movie can catch up to a moving light particle.

Andreas Velten, a postdoc and one of the developers of the streak camera describes the device as the “ultimate in slow motion. There’s nothing in this universe that looks fast to this camera.” As a result of the efficiency of this system, it is estimated that the camera can achieve up to a trillion frames per second. For a reference point, the two slow motion videos at the beginning of this post were shot at most 5000 frames per second.

Thankfully, this technology may not just used for making cool YouTube videos. Associate Professor Ramesh Raskar states, “The camera may be useful for medical imaging […] now we can do ultrasound with light because we can analyse how light scatters volumetrically inside the body.” Eventually, he adds, that this technology can be applied to consumer photography as well. So whether you would like to make a video of how light scatters around your room, or you would like to use light to look inside organs, the future looks bright with this new imaging system.

References:

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