Professor Sir Harry Kroto FRS - Oral Evidence Summary

This evidence was taken at a meeting of the working group on October 30th 2003 and was written up by the secretariat. It has been approved by Professor Kroto.

Definition of Nanotechnology Nanoscience

Professor Kroto took the view that Nanoscience and Nanotechnology (N&N) could encompass almost all of chemistry as well as molecular physics and molecular biology with an emphasis precise structures and function at nanoscale dimensions. As such it also included much of modern materials science - In particular where the advances in properties involved an intrinsic atomic/molecular perspective. He commented that chemists had over many years being trying to build larger and larger molecules and were now beginning to create large molecules with specific intrinsic functions. As an example he mentioned that Haemoglobin, which had been discovered fifty years ago, had revealed the fact that molecules could act as machines. Now there is significant work on developing and refining biological synthesis technology to create new molecular machines.

As far as definitions for the purpose of funding were concerned, Professor Kroto noted that the prefix “nano” had often been used by researchers in obtaining funding. This was thought to be inevitable, but not particularly useful and possibly led to a degree of hype in the claimed benefits of nanotechnology. It was his view that a researcher in almost any branch of chemistry, molecular physics or molecular biology would be able to frame a proposal to a N&N funding initiative with a reasonable chance of success. His view was that N&N is essentially the Chemistry of the 21st Century

Asked if his definition dismissed inorganic applications Professor Kroto stated that he saw that the development of absolutely accurate control of small crystalline structures to atomic precision, particularly with new zeolitic-type structures as but one very exciting avenue.

Complex Molecular Machines

Professor Kroto did not believe that Dr Drexler’s scenario of molecular manufacturing could be achieved, especially not if it was envisaged as building microscopic analogues on an atomic scale of everyday objects, such as cars. Professor Kroto thought that the only things that remotely fitted the scenario at present are enzymes and molecular complexes such as the ribosome, however, the type of manufacturing that adapted versions of these could do would take too long. However, it was noted that biological systems have somehow managed to crack this shortcoming. Drexler appeared to believe that metal or refractory equivalents of the components that biology has created are possible but there is no refractory chemistry that remotely compares with the genius of bio-organic chemistry in aqueous media and Drexler has not to his (Professor Kroto’s) knowledge posited an alternative chemical technology.

The present state of such “refractory” technology was described as being able to move and place individual atoms on a flat surface, but there was still the truly fundamental issue (which seems to have escaped the many non-scientists’ awareness and in particular Drexler’s) of how to make the atoms bind together and he did not see how this would be overcome as atoms are linked together by the highly stringent chemical regulations that govern how the elements of the periodic table can link together. As a rough physical analogy two magnets cannot be placed near each other in any desired position or orientation because of the mutual forces involved. IBM scientists had demonstrated the ability to move atoms – one by one, but had yet to actually make any useful device this way.

Professor Kroto felt that the macro concept of machines had to be different to the nano concept. For instance, although an electric motor and ATP synthase might have physical analogies with one another, their modes of operation are radically different. He also commented that at the scales talked about, he conjectured that microscopic fluctuations such as those involved in Brownian motion, fluid dynamics and other disruptive effects that occur at the molecular level would probably become very important and would also have to be overcome. One example in say molecular scale devices would be the disruptive effects of for instance cosmic ray particles which probably would be very important at atomic scales. When told that Dr Drexler had envisaged machines with 1021 atoms, Professor Kroto thought that that was quite big as Avogadro’s number was 6x1024.

Future Prospects

Professor Kroto felt that we (or definitely he!) could not predict future developments more than a few years away and history indicated neither could anyone else, so it was not productive to look for future problems when today’s (which are massive – from global warming and sustainable energy supplies to malaria and fresh water supplies - had yet to be sorted out. He stated that viruses are currently as close to replicating nanomachines as he could envisage today and this is hardly a new issue as we have known about them for much of the last century. They do replicate and can be extremely dangerous. More effort should be put into dealing with them than worrying about hypothetical potential dangers of the future. As this fairly “old” field is now considered to be nanoscience it is an indicator of the problems that now face us in considering the future of N&N.

On the prospects of man-made self-replicators, Professor Kroto stated that we could not envisage a non-biological macro self-replicating machine. A mosquito can do it, but the closest we have got to such a machine is a helicopter and he could not envisage the creation of even a helicopter that could self-replicate in the foreseeable future. In summary, he felt that we do not know how to make pseudo-biological systems that can replicate to even conceive of non-biological replicators. Asked if Dr Drexler’s scenario could be described as a man-made life form, he felt that it could be so described, but still could not envisage how it could be done. Indeed he thought that Drexler should sit down with engineers and consider how one might build a macroscopic self-replicating device that could be considered to be “living” before thinking about how to devise a microscopic one. He could envisage the former but not the latter – but that may just that he has the “limitations” of knowing some chemistry.

Scientists, Communication and Risk

Scientists have a tendency to never rule out any possible future development and this has is generally misunderstood as far as the general publics’ perception of risk is concerned. Professor Kroto agreed that scientists on the whole “never say never” about anything that cannot be categorically disproved. Decisions however must often be taken on some common sense basis dependent on some sort of scientific analysis of future implications.

Addressing the public perception of risk, Professor Kroto felt that the elimination of all risk would eliminate research and stop progress. As an example, he suggested that if similar discussions had taken place 100 years ago (in say 1903) on the possible dangers of Chemistry, some might have foreseen problems eg nerve gas, Thalidomide and the Bhopal disaster. If society had taken a similar risk adverse stance then, to the one which some are advocating today with regard to N&N, most of the scientific breakthroughs of the last century would not have been made eg. Penicillin and DDT would not have been discovered and they have saved the lives of countless millions (100 million people?), the Haber process produces the fertiliser for the crops that feed at least half the world and we would not have computers or modern polymers etc. This attitude to risk may have grown up because modern technologies are now so powerful that in the wrong hands they may indeed threaten the whole world. The atomic bomb is but one example. Prof Kroto sees this as a problem.

Professor Kroto felt that little was known about the toxic effects of nanoparticles but felt that carbon nanotubes should be fairly benign based on the fact that graphite is. He thought that there was no analogy with the asbestos fibres, which have totally different aerodynamics and are much more readily carried in the air and deep into the lungs. A comparison with soot is also not appropriate at the carcinogenic agents in soots are the associated organic compounds

When asked about the problems that may be encountered when products containing nanotubes reach the end of their useful lives, Professor Kroto agreed that sustainability was an issue and an issue that had to be tackled by all manufacturing industry, not just nanotechnology. This is an issue that strikes right at the heart of the philosophies driving modern manufacturing and it will have to change. Although accepting that regulation was inevitable, he did express a view that not enough well-trained scientists were involved in the formulation of regulations and the associated risk assessment criteria.

Commenting on science communication, Professor Kroto thought that scientists are doing a reasonable job, but the lack of scientific understanding among journalists meant that the main interface with the public, the newspapers, reported some science badly. He said that this had been born out during the GM debate.

Future Applications

As a fundamental scientist, Professor Kroto did not feel that he was in a position to give very authoritative views on future nanotech applications. In his own field of fullerenes and nanotubes, however, he did think that their ballistic conductive properties would lead to applications in the microelectronics field and photovoltaics. He added that the major benefit to be gained from using fullerenes and nanotubes in these applications would be significantly reduced power consumption in nanoscale electronics as well as advanced materials behaviour in civil engineering. Sustainability should be high on the list of priorities for developers and researchers.


Although early concerns on the toxicity of the fullerenes that he worked with have been shown to be unfounded at least in the short term, Professor Kroto did believe that regulation was important and that long-term toxicity studies should proceed hand-in-hand with further fundamental research. Asked if the current regulatory framework could cope with all aspects of nano-materials, he thought probably not and that there should be some involvement of government labs in the formulation of reasonable new frameworks.

However Professor Kroto also felt that no system of regulation could prevent all future disasters. Such disasters were an unavoidable consequence of scientific progress. Regulations could never be perfect in preventing all possible occurrences, but at the same time, the wrong safeguards could be worse than no safeguards at all. An archetypal example of the “ethical” problems we face in this sphere is fact that DDT almost wiped out malaria but the recent reduction in its use has led to a situation where now an estimated 2.7 million people are dying each year of the disease. There are thus dangers that regulations put in place for good reason can be used in ways in which they were not originally intended and have unforeseen consequences. Prof Kroto sees careful debate on these sorts of issues is of crucial socio-scientific importance.