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| SCIENCE & TECHNOLOGY |
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Heralding a new future Prof Yash
Pal
THIS UNIVERSE |
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Heralding a new future IN 1965, the movie Fantastic Voyage told of a microscopic submarine full of medical exports shrunk to cellular size. Their mission was to navigate the body of a dying scientist and save his life. It was a science fiction then, but that fantastic voyage is actually happening today with the emergence of nanotechnology, a science that puts the arcane and bizarre discoveries of particle physics to work on real-life biological problems like tumor detection, crystal clear imagery of blood vessels and tissues hidden deep within the body, medical tests that provide instant results, revolutionary methods for defeating cancer, AIDS and other major diseases.
Under the new roadmap of our national programme in the field of nanotechnology, nanomedicine has been given top priority. Now, research discoveries in the field would help doctors detect diseases like cancer in their earliest stages and devise treatment to stop them in their tracks. Nanoparticles like quantum dots (QDs) and dendrimers would reveal tumours that could be either destroyed by the nanoparticles or removed by precise surgery. They would help locate signs of genetic susceptibility to health problems and fight bad genes with good one. Researchers would have to explore ways and devices to detect a predisposition to cystic fibrosis or the disease itself in embryos and eliminate the problem with genetic treatments. Also, they would make giant strides towards understanding and countering the ageing process where it begins inside the body cells. Nano (the Greek word for dwarf) is billionth of a metre about the width of 10 hydrogen atoms line up in a row. In comparison, a red blood cell is veritable gorilla, measuring 8,000 nanometers. Vapourising carbon and letting it condense in an inert gas to produce crystals, scientists and technologists are able to construct unimaginably tiny tubes, spheres, shells, flakes and other complex nanoparticles. QDs glow in various colours when excited by a laser source. They are customised to tag specific proteins that perform key chores inside cells. They provide extended, real-time images of healthy and diseased cells at work. Such life images further provide a better understanding of how the cell process work and it might allow researchers to watch close and track as cells react to medications and treatments, including some used against cancer detection and its elimination. Medical scientists gave QDs a special coating that enabled them to enter lab animals’ tissues and send back trackable signals for many months. Eventually, these particles can be treated with substances that seek out specific tumours and then be entered into body, tracked by laser technology and visualised through nanoscopes, illuminate tumours. Doctors can trace them with greater accuracy and precision. Later, QDs can be used to deliver antibodies or drugs. During preliminary tests at Rice University in Houston, “nanocells” have been proved to eradicate tumours in lab animals. Twenty times smaller than a red blood cell, a nanocell consists of a silica core covered by a thin layer of pure gold. Because of nanosize, this is able to pass through the blood vessels of tumour and get collected inside it. Then, near-infrared light (780-1100 nm) is aimed at the tumour that passes harmlessly through the soft tissue and strikes the gold-coated nanocells, raising the temperature the same way sunlight heats a car’s metal roof. Then the concentrated heat destroys the tumour. Women may be among such technologies earliest beneficiaries and first medical use of nanotech tools will be against breast cancer. This disease spreads through the lymph nodes that should be removed along with tumor if they have been affected by the cancer. At present surgeons inject radioactive dyes to try to locate “sentinel nodes”. QDs in place of radioactive dyes gives surgeons a quicker and most precise picture from where the diseased nodes begin and terminate. A nanotechnology device—the size of a cell phone—has been developed that permits people on blood thinning (anticoagulant) medication to take their own blood clotting readings at home. The device analyses microscopic particles and take readings by targeting proteins involved in the clotting process through a microcontroller/labtop-based system. Determining the right anti-coagulant dose till date has always been a process of trial and error, but the said device would calculate the specific dose more precisely and accurately. Nanotechnology is also improving genetic testing and gene therapy. Researchers are exploring ways to test embryos for inherited cystic fibrosis (CF) prior to in-vitro fertilisation, using nanoparticles that glow when they encounter compounds produces by the CF gene. Biologists and technicians are testing the feasibility of compressing healthy DNA strands from about 200 nm to less than 25 nm in order to slip healthy genes through the cell membranes of people who have CF and other genetic disorders. The healthy genes would force the cells to perform normally. Other researchers are trying to build better artificial joints and implants with rolled up sheets of carbon atoms (nanotubes). Studies have found that bone cells called osteoblasts bond to titanium coated with nanotubes better than to regular titanium and there will be lesser chances of ball and socket of a surgically implanted artificial hip joint to get loose. Even the war against AIDS can be fought barefooted with nanotechnology weapons. The Australian nanotechnology firm Starfarma has developed an anti-HIV vaginal gel. When the gel containing specific proteins is inserted prior to sex, it prevents the virus from infecting healthy cells. The nanotech components of gel are dendrimers—super tiny, snowflake like molecules to which all sorts of medical substances can be attached for special delivery. Dendrimers have also been tested as cancer fighter. The nanotechnology-based nanobot can be used as an artery cleaner. The nanobot when inserted through blood vessels can send and receive instructions and data from a control outside the body. The nanobot would either remain inside the blood system, constantly performing its task or it would be programmed to become biodegradable safely, carrying the waste plaque out of the body. Nanotechnology textile-based aprons can be suitably used by patients and doctors in operation theatre, ICU wards and medical centres to prevent against communicable diseases and viruses. Because viruses do not stick to such aprons and these infected virus and bacterias can be thrown with a simple jerk and laminar flow of air. Nanotechnology has now entered the shelves of health and beauty aid products. Among such cosmetic products are heavy duty sunscreens made from zinc oxide particles, so tiny that they go on clear instead of chalky white as traditional zinc oxide creams do. Zinc oxide offers superior protection from sunburn apart from protection against UV radiations. The ultimate potential of nanotech therapies is limitless. Some scientists envision nanosize molecular machines with gears and propellers and built-in power tools. Getting the molecular scale control is extremely relevant to medicine. Disease begins with molecular level damage. If we can send in nano-repair kits for such breakdowns, including cancer, the medical benefits are immense. The focus is not only on disease but also on ordinary ravages of time, since we don’t know a lot about “ageing”. But it is definitely a process due to cellular degradation. The little nanomachines inside our cells start to breakdown. If we had some other nanomachines that could go inside our cells and repair the breakdown to the state it was in when it was young and healthy, we might be able to repair the organism and counteract the ageing. A breakthrough could be just a few years away. The writer is a former scientist, CSIO, Chandigarh
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THIS UNIVERSE Gravity at the centre of the earth is zero, but mathematically gravity is infinite at the centre. Please explain. Sometimes it is dangerous to mug up formulae without understanding matters. Imagine you are at the centre of the earth - at the dead centre of a completely spherical earth. Then all the particles of the earth will be attracting you, but the attraction from different directions will cancel each other and you will find yourself to be weightless. Where is the contradiction? Why does not glue stick to the inside of a bottle? All materials do not have attraction for each other. For instance, water sticks to glass but mercury does not. The reason that gum does not stick to its containing bottle is because of chemical incompatibility of materials. You must have found that we have non-stick pans in our kitchens in which the oil does not stick, while it does in ordinary steel or brass pans. If the glue were stored in a container made of paper it would definitely stick. A person drowns in water when he is alive, but his dead body floats. Why? The average density of a human body is about the same as that of water. We do not naturally float and live because our head is heavier and our nose and mouth go into the water to stop our breathing. Water filling up our lungs brings the end. When we are dead, we do not mind our breathing apparatus being submerged. In that event, floating is natural.
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