2023-11-20 12:52:37
The Hungarian physicist tries to detect malignant tumors in such early stages that it is easy to cure them.
Like astronaut Neil Armstrong when he planted his left foot on the Moon, Hungarian physicist Ferenc Krausz was the first person to peer into an unknown world: that of electrons, the elusive particles that act as glue for all known matter. On the night of September 10-11, 2001, around five in the morning, Krausz’s team managed to produce ultrashort laser light pulses of 650 attoseconds: trillionths of a second. For the first time, humanity had a flash so fleeting that it allowed the movement of electrons to be photographed, but the physicist did not have time to enjoy its success. “When I returned to the office the next day, I was faced with the terrible images of the World Trade Center destroyed by terrorist attacks,” he recalls via video conference.
The Hungarian scientist, born in the wine-growing town of Mór 61 years ago, won the Nobel Prize in Physics a month ago. Krausz is one of the four directors of the prestigious Max Planck Institute for Quantum Optics, in Garching, Germany. There, his team is looking for applications for this attosecond camera. In February, after winning the BBVA Foundation’s Frontiers Award, he predicted what the first application in the real world will be: detecting cancer in such early stages that it will be easy to cure it.
Ask. How do they intend to detect cancer so early?
Answer. Attosecond technology was created to capture the movement of electrons on this time scale, but, in parallel, it also turned out to be very useful for capturing another phenomenon: the oscillations of the electric field of light. Basically, we take a very short pulse of infrared light and focus it on a human blood sample. Or, rather, from blood plasma, because the cells have been removed, only molecules remain. It’s not even red, because the red blood cells have been removed first. It has a yellowish color and contains hundreds of thousands of different molecules. In medicine, it is known that, in a healthy organism, the concentration of these molecules is in a very narrow range. Some of them are already used in routine laboratory analysis: they measure their concentration and compare it with the reference ranges in healthy people. This is very useful, but fails to provide a complete picture of your health status. Many diseases do not have a biomarker, or at least have not been discovered.
Q. Still.
A. That is why there is a gigantic biomarker research industry. Pharmaceutical companies spend billions of euros each year searching for new biomarkers, with which to recognize diseases as soon as possible and be able to cure them or, at least, stop them. The typical example is cancer: you want to detect it as early as possible, because then you will have a better chance of curing it. There is enormous pressure to find new biomarkers that allow early diagnosis, but it is like looking for a needle in a haystack. Let’s look at the example of an existing biomarker, prostate-specific antigen (PSA), which is used to detect prostate cancer. Its concentration also increases a lot with a simple inflammation in your body, which shows that it is a problematic matter. We have chosen a completely different approach. We do not want to select individual molecules, but rather we are looking for a method that can address all molecules. It is like the musician who hits a tuning fork to tune his instrument. We take short pulses of infrared light, which play the role of a mallet. The molecule is the tuning fork. We hit it very briefly and it starts to vibrate. The excited molecule does not generate sound waves, but infrared light. And the frequency of these infrared waves is specific to each molecule. That’s the idea. We obtain blood samples from healthy people and from patients with a certain disease, for example, lung cancer. We measure and try to find out if lung cancer creates a specific pattern in this infrared molecular fingerprint of the blood sample. And the answer is yes.
Physicist Ferenc Krausz toasted with his colleagues in Munich (Germany) after being awarded the Nobel Prize in Physics, on October 3.ANNA SZILAGYI (EFE)
Q. How reliable is it?
A. The signal is quite significant. That’s why we think we’ve discovered a very promising way to detect lung cancer. And not only in stage 4 of the tumor, when there are no longer opportunities to save you, which is when it is diagnosed now in most cases. That stage is basically a death sentence. Half of lung cancer diagnoses in the world are stage 4, so every year a million people learn that they only have one more year to live. The goal is to detect the tumor earlier, in phases 1 or 2, or at least in phase 3, when it has not yet spread throughout your brain, your bones and throughout your body. With our method, we can detect lung cancer with an efficiency of 90% in phase 4, 75% in phase 2 and 56% in phase 1. There is still room for improvement, but we see very clear signs that will allow us to optimize the method. We have also investigated seven other types of cancer, such as breast, prostate, bladder and colon. In all of them we have been able to detect a very distinctive infrared light signature.
Q. When could real applications arrive?
A. There is a long way to go. First of all, we must validate this method. So far we have carried out tests on 500 samples from patients and another 1,000 from healthy people. The method seems effective and promising, but to reach clinical applications you need to validate it with many thousands of samples. We will need years to obtain them, because most diagnoses are made in phase 4. People do not go to the doctor before because they do not have symptoms. And, if there is no diagnosis, there are no samples to validate our method. We are forming an alliance with the main hospital centers in Germany to try to obtain thousands of samples from lung cancer patients. We’ll need another five years or so.
We have room to improve the power of computers 100,000 times
Q. When talking about electrons, everyone thinks of electronic devices, but human beings are also part electrons.
A. Yes, electrons play an absolutely crucial role in our lives, both biological and technological. Electrons act like the glue that makes atoms form molecules. And molecules, like proteins, are the smallest functional units of every living thing. We know that any change in the structure of these basic building blocks of life can have very serious consequences, leading to dangerous diseases, such as cancer. And these changes in structure always involve the movement of electrons. For a long time, chemists believed that femtoseconds [milbillonésimas partes de un segundo, o sea mil veces más largos que un attosegundo] were the fastest of the relevant time scales for molecules. On that scale, other people did pioneering experiments, such as Ahmed Zewail, who won the 1999 Nobel Prize in Chemistry for creating the field of femtochemistry. People believed that faster time scales were not relevant, but that has changed. We now know that the movement of electrons on the ultrafast scale of attoseconds can predetermine the reactions that will occur next and which chemical bonds will be broken or transformed to give rise to a new structure. This is how the field of attochemistry has emerged.
Q. Do you think there will be technological applications?
A. We know that we depend on the devices we use every day, such as the laptops thanks to which we are having this conversation. The speed at which we can turn electrical current on and off has been stagnant for almost two decades. This speed is about 10 gigahertz: that is 10 billion times per second that we can turn the electrical current on and off in the current chips integrated into our mobile phones and computers. This is enormous power, but there is a constant demand for more capacity to run ever faster calculations. For example, even current supercomputers are unable to predict phenomena as complex as earthquakes. Obviously, there is a need to increase power.
Q. How?
A. There are two possibilities to achieve this: one is to achieve greater miniaturization, to be able to integrate even more transistors in the same volume, but this possibility is reaching its limits, because we are already reaching nanocircuits in the 10 nanometer range. It’s not far from atomic dimensions, and it’s hard to imagine how a single atom could form a transistor. So the only dimension left is the fourth dimension: time. We have used attosecond technology to explore what potential is available in this way. Last year we published that, under laboratory conditions, we can turn current on or off with the electric field of visible light, which oscillates up and down about 100,000 times more than the microwaves that turn current on and off in today’s electronics. So we have room to improve 100,000 times. Manuel Ansede (EP)
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