On the cutting edge
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| Prof Sarit Kumar Das |
Area of research: Nanofluids, nanobiotechnology, heat and mass transfer, two phase flow, heat exchangers, fuel cells.
Motivation: My general expertise is in heat and mass transfer and hence my preliminary choice was in the application areas like power and nuclear industries. However, I was amazed by the introduction of nanotechnology and biology and their integration into main stream engineering research. The pleasure of finding new things and revealing the secrets of nature, and utilising this towards serving mankind is what drives a researcher. Even today I work tirelessly and sleep for five hours a day.
Nano enabled tumour ablation
It was during my sabbatical at MIT, Cambridge USA as a visiting professor during 2007-08 when a paper on tumour ablation from Prof Sangeeta Bhatia of MIT – Harvard combined institute (HST) came to my notice. Working with Geoffrey von Maltzahn, a student of hers, I started working towards an efficient way to ablate tumours. Infrared laser when used, results in cancerous tissues scattering the laser radiation more than they absorb thus damaging neighbouring tissues. In our experiments, we injected gold nanorods that accumulated in the tumour thus increasing the absorption of laser radiation significantly and ablating small tumours succesfully. A computer model to predict the parameters required for this therapy, like time and power of the laser for a given size of tumour and required amount of nano particles etc was also developed. This was a pathbreaking work which was published in Journal of Cancer Research and happens to be a very well referred article worldwide.
Targeted drug delivery
Quite often in cancer patients undergoing chemotherapy, the drug needs to be injected in higher dosage(hundreds of milligrams instead of couple of micrograms). After few such sessions, patients end up at a high risk of death due to destruction of the immune system. Our research is looking at delivering a drug in the right dosage at the right place. Gold particles are tagged with the drug alongwith a small stretch of DNA which is then inserted into the body. Cancer cells detect a protein that the gold particles are coated with and attach themselves. Once this happens, the temperature of the gold particle is raised externeally to 42 degrees, at which, the DNA melts and the drug is released. We have completed computational work and preliminary invitro experiments and now need to shift to in vivo experiments. Work on such nano-enabled drug delivery is still in nascent stage internationally and offers hope to those suffering from cancer in terms of better treatment options.
Commercialisation is not the only aim of research
A researcher in technology aims to innovate his work so that it can be commercialised. However, commercialisation is not the only aim of research. There are many areas in which developing the knowledge is more important. For example, fuel cell has been known for more than half a century. Research in 70s and 80s did not produce a product in the market but paved the way for understanding and development. A multi-disciplinary approach along with sustained research will help create technological products of the future. It goes without saying that the infrastructure of research in this country, although improved in the last decade, is far below that of not only the advanced countries but also the countries like Korea, Taiwan and China. India needs to spend at least five times more in research to compete internationally.
– Prof Sarit Kumar Das, Dept of Mechanical Engineering, IIT Madras
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| Dr Murali Sastry |
Areas of work: Studying the the interface between inorganic nano materials and biological molecules (such as amino acids, proteins and DNA) and systems (microbes).
Driven by curiosity: While I was at the National Chemical Laboratory(NCL) Pune, the field of nanotechnology was in its infancy. There were many gaps in understanding nano processes at a fundamental level that I wanted to address and contribute to and then use this knowledge to develop processes with commercial value. The opportunity to work at the intersection of physics, chemistry and biology was tremendously exciting and motivating. NCL provided the right environment to come into contact with scientists from diverse backgrounds that helped me come up with breakthrough ideas in my field of research.
Tough times fuelled innovation
I started my research career in India on returning from Italy in 1991. Those were tough times for young researchers and funding was difficult and hard to come by. That forced many of us to be more innovative and use infrastructure optimally. I believe it pushed me to ask deeper questions and be more innovative in my approach to research and indeed, the sort of problems to address. There is much merit in starting out the hard way, which I notice is becoming increasingly rare in the current scenario.
Low cost nano-based water purifier
At Tata Chemicals, my research became more application oriented and I focused on using nanotechnology to address challenges related to safe drinking water and agriculture. Rice husk ash- a by-product of the combustion of rice husk during milling of rice is traditionally used in rural areas as a toothpowder and also as a water purifier. TCS was already working on a rice husk-based water purifier- a basic product called Sujal, which was used in disaster relief like the Bhuj earthquake and during the tsunami. However, Sujal could not be used for large scale rural or urban population since it could remove impurities but not microbial contamination, which is responsible for waterborne diseases caused due to pathogens. At Tata Chemicals, when we were asked to design a water purifier, we looked at nanotechnology to provide a solution. We inserted nano silver, a potent antimicrobial agent into rice husk to further enhance the purification by removing gram positive and gram negative bacteria and viruses to a certain extent. The product has been tested as per US Environmental Protection Agency guidelines and is completely chemical free.
Inorganic nano particles using microorganisms
Working with my students at National Chemical laboratory, Pune, I was involved in developing inorganic nanomaterials such as metals, metal sulphides and oxides using microorganisms such as bacteria, fungi. Termed as direct evolution, the process involves subjecting microorganisms to stress.
A big ‘aha’ moment was when we serendipitously discovered a bacterium that could convert metal complexes to oxide nanoparticles. I am proud that we were the first group in the world to have done this sort of research. We also used plant extracts from tamarind leaves, lemon grass, neem etc. We created a new school of thought and put India on the world map in the area of nano biotechnology. For quite some time, my lab at NCL was ranked number 4 in the world and I was consistently ranked within three top 10 nano scientists globally (based on research output and citations). This is totally a green process unlike standard fermentation in industries. Although it has not found a commercial application yet, it is completely scalable.
– Dr Murali Sastry, Director – Innovation Center, DSM India
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