Nobel Prizes 2018: science for humanity

This year, the Nobel Prizes for physics, chemistry, and medicine have been awarded for work primarily done two or three decades ago with a significant impact on our everyday lives. All science prizes this year have led to large commercial and industrial enterprises benefiting humanity, and in particular, health and environment.

Physics

The 2018 Nobel Prize in Physics was awarded for pioneering work on laser technology and its applications. Half the prize goes to Arthur Ashkin who at 96 becomes the oldest person ever to get a Nobel. More than 30 years ago, he invented optical tweezers with laser light pressure serving as pincers to manipulate, grab and trap microscopic objects including atoms, viruses, and living cells, to study various aspects of biological and atomic processes. Living bacteria are captured without harming them, enabling study of machinery of living systems.

Sunlight also exerts pressure which on the surface of the earth corresponds to about half a newton per square metre. However, laser beams being coherent emit much higher pressures, with the ultrapowerful petawatt lasers exerting millions of atmospheres of pressure. They are used, for instance, to heat plasma to millions of degrees temperature to initiate nuclear fusion reactions in the laboratory.

The other half of the prize is shared by Gérard Mourou of France and Donna Strickland of Canada. Donna happens to be the third woman ever and the first in 55 years to get the physics prize. The duo developed a technique called Chirped Pulse Amplification (CPA) to boost laser pulses to immense intensity (terawatt or petawatt). Their technique involves first stretching the laser pulses in time to lower their peak power, then amplifying them and finally compressing the pulse duration considerably, increasing intensity.

Before their work, the peak power of laser pulses was limited and moreover the materials used were damaged. When the laser pulse is temporally compressed and becomes shorter, more power is packed into a small duration and region of space. Thus we have ultrashort, ultrapowerful picosecond terawatt (or femtosecond petawatt) laser pulses. This became the standard technique for producing high intensity lasers which have found umpteen applications including laser eye surgery, laser therapy, targeting cancer cells, micromachining, high precision measurements, etc. In short, their work has revolutionised laser technology and its countless applications.

Chemistry

Frances Arnold (US), and George Smith (US) along with Sir Gregory Winter (UK) shared this year’s Chemistry Nobel Prize. They were cited for applying Darwinian principles of evolution to develop enzyme catalysts enabling the production of innumerable products like antibody drugs, biofuels, detergenwts, etc.

Arnold becomes only the fifth woman to get a chemistry Nobel. Arnold’s method of rewriting DNA to mimic evolutionary changes has enabled solutions such as replacing toxic fossil fuels with a variety of biofuels like those derived from sugarcane. Also, more chemical substances less damaging to the environment have been developed including detergents, antibodies, neutralise toxins, etc.

Winter, a genetic engineer, and Smith pioneered a technique known as phage display, wherein a bacteriophage can be harnessed to evolve new protein. This work has led to the production of patented medicines for a whole host of ailments ranging from arthritis, psoriasis, bowel diseases, etc as also antibodies to counteract autoimmune diseases, cancer and to neutralise toxins. Some of the world’s top-selling prescriptions resulting from the work include Humira drug for arthritis.

The scientists have used the principles of evolution, involving genetic change and selection, to develop new proteins used in a wide range of applications. This is dubbed as directed evolution. An example is a fish able to swim in polar seas as they have evolved to develop anti-freeze proteins in their blood. They have speeded up the evolutionary process, thousands of times, redirecting it to create new protein.

In summary, the work leading to the prize involved harnessing the power of evolution (in laboratory) to produce novel proteins, catalysing and making of everything from green fuels to cancer drugs, detergents, new medicines etc.

Medicine

For their pioneering work in the discovery of how to fight and cure cancer by harnessing and manipulating the body’s own immune system, the Nobel Prize for Medicine was shared by James Allison of the US and Tasuku Honjo of Japan.

The work, done about 30 years ago, has led to improved therapies for melanoma, lung cancer etc which were earlier very difficult to treat. Allison and Honjo’s seminal work was directed at proteins that act as brakes on the body’s immune system, preventing the immune cells known as T cells from attacking tumours effectively and how different strategies for inhibiting these brakes can be used in treatments known as ‘immune checkpoint blockade’.

Allison worked on a protein called CTLA-4 realising that if this could be blocked, a brake would be released rapidly unleashing the body’s own immune cells to attack the tumours. Honjo separately discovered a second protein called PD-1, which also acts as an immune system brake, but with a different operating mechanism. The resulting drugs targeting PD-1 blockade proved a big commercial hit, leading in turn to the creation of a multibillion dollar market for new cancer medicines.

The booming field of immunotherapy is still in its infancy and the immune checkpoint blockade therapy’s possibilities would be mindboggling for the future of modern medicine.

(The writer is with Indian Institute of Astrophysics, Bengaluru)