Andrew deMello has come a long way in a short time. Katharine Sanderson went to meet him to find out how doing reactions on a tiny scale has made such a huge impact on his career.

Andrew deMello has come a long way in a short time. Katharine Sanderson went to meet him to find out how doing reactions on a tiny scale has made such a huge impact on his career.

Listen closely to any of Andrew deMello’s lectures and you might notice a bit of artistic licence creeping in when he’s describing coloured aspects of his work. 


The 33 year old senior lecturer in chemistry at Imperial College London admits to being colour blind, but claims that he manages to get away with it in his teaching. For a man who is so passionate about using practical demonstrations to spark interest in science, his first experiences in the lab were somewhat frustrating. During a titration in his A-level practical exam being colour blind meant that he had to ask his teacher every few seconds whether the colour change had happened. It is interesting to ponder who would have been most frustrated by this, the teacher, or the teenager who was about to embark on a remarkable academic career which would see him become one of the leaders in the pioneering field of microfluidics and lab-on-a-chip devices.

A London boy at heart, deMello began his education at John Lyon School in Harrow on the Hill, where an inspirational chemistry teacher captured his imagination. ’He just completely turned me on about chemistry. He did a lot of demonstrations in classes and he just had a real enthusiasm for the subject. I guess further on that’s why demonstrations and practicals are kind of important to me.’ DeMello enrolled on an undergraduate course in chemistry at Imperial College London. Despite this initial love for the subject, chemistry almost lost deMello to other things, until the arrival of two key figures at Imperial College. David Phillips and Garry Rumbles arrived from the Royal Institution and brought with them their expertise in photophysics. Phillips lectured the undergraduates in atmospheric chemistry and photophysics, and along with Rumbles was doing some pretty exciting research. DeMello explains how this was a major turning point for him: ’After my second undergraduate year of chemistry I wasn’t thinking of doing chemistry. You know, you work hard and other things spark your interest. But Garry was doing a lot of research into spectroscopy and laser technology and lasers are really cool things to play with’.

Which gives a hint at his main reason for staying on at Imperial to do a PhD: ’I really wanted to play with lasers’. But behind this seemingly light-hearted decision lurked the real ambition that has obviously driven deMello to get so far, so quickly, ’the other reason why a PhD was attractive was that I wanted to move to the States to do a postdoc and that was one of the prime reasons that I stayed at Imperial College to do my PhD.’

In 1996, deMello left behind the sunshine of California to take up a lectureship at the University of East Anglia (UEA), UK. He had always planned a return to the UK. ’In an ideological sense I did feel after I did my PhD degree that if things went well and my postdoctoral work progressed that I would come back to the UK and give something back to the system.’ And the position at UEA was the perfect chance to do just this. The physical chemistry lectureship ’was really in an area that fitted me down to the ground and I thought it was a really good opportunity’.

deMello has amassed an impressive portfolio of research grants, and his experiences in the US seem to have highlighted to him the importance of getting the right balance of funding. His feeling is that multidisciplinary research and brave, expansive funding programmes allow scientists infinitely more freedom to develop innovative new technologies. ’The environment in the US is wonderful for research because there is quite a different focus on the ability to do research out there: there’s a lot more money and you can do things that are a bit more difficult to do here [in the UK].’ He takes his post-doctoral experiences in the US as the example: ’In the very early days the support for all the development of microfluidic systems for genome and DNA analysis was incredibly well funded by the US Department of Energy and the Human Genome Project. It meant that you could really throw significant amounts of money at the problem. It wasn’t just one university, it was a number of universities. There was a chance to make big improvements. In the US they can do that because the research infrastructure and the money allows you to spend much more. I guess it’s a different situation here, because we have tighter finances. I think the UK should be braver at deciding what the important problems are very early on and then direct or target significant money into those areas. This gives us a chance to do very novel work. The danger in any environment where you have tighter finances is that you can’t do that so much. I think it’s important that you target significant chunks of money and say "let’s see what we can do in this area".’

Collaboration is key 
Applying technology and research to real problems is the key. Basic research can be funded by a research council, for example, and the development can then be picked up by an industrial body with the capability to turn a well-researched idea into a real application. This is where deMello’s enthusiasm for the multidisciplinary nature of research is most apparent, and is linked to the freedom that he feels academic life provides him with. ’Collaboration is an incredibly important aspect of research and being within an institution like Imperial College you have colleagues who are in biology, in medicine, in physics and engineering. And in my field the key to being successful is multidisciplinarity. It’s very simple - you need a really broad skills base and you need people who can understand the way microfluids behave within micrometre and nanoscale channels. You need people who can build these devices, which again requires a very special expertise. You then need chemists and biologists who actually understand how processes such as reactions work. And that becomes really tough when you go down to these really small scales. You’re in a very, very different environment to the environment where "normal" chemists and biologists work. It’s a different regime to be working under so you need people who understand those aspects. You then really need to bring in pure physical science with the engineers and mathematicians who understand and can model the way fluids behave.’

Branching into business 
As proof positive of his wish for science to become more multidisciplinary, deMello has recently set up his own company. Molecular Vision is a joint venture between him, Professor Donal Bradley from the physics department at Imperial College, and John deMello, his physicist brother, who also happens to conduct his research in the chemistry department at Imperial. deMello the chemist seems to be relishing the opportunity to become involved in business. ’In a way it’s fun. It’s good to do something like that because it teaches you new things, and you see how difficult it is to generate money to develop ideas in a commercial sense.’ The company is focused on combining existing technologies to make new miniature devices. It’s a new direction for deMello’s research that makes use of the ability to control reactions on the microscale that he has developed for his microfluidic devices. His technology is now being linked to nanoscience and has ’shown that we can control the size of things like nanoparticles and quantum dots just by controlling and varying reaction conditions in ways that you can’t do on a large scale. That’s really exciting because in terms of future materials, the ability to control the size, structure and shape of nanomaterials is going to lead to a huge number of new materials with really unique properties’.

Now that deMello is hot-footing it up the academic career ladder, perhaps, like Phillips and Rumbles were to him, he will be able to inspire the next generation of scientists, be they chemists, physicists, biologists or engineers. Perhaps he already has done so in one of his beloved demonstration lectures: ’One of the most interesting lectures I ever gave was to a bunch of six and seven year old American school kids who knew very little about anything to do with science’, he says. Don’t tell that to his students at Imperial College.

Microfluidics in a nutshell

Research in deMello’s labs is all about taking the ideas of miniaturisation and using them to gain added value and some advantage over conventional technologies. Welcome to the world of microfluidics. The devices that his group are looking to incorporate components that are only micrometres wide. In conventional reaction vessels, such as the humble test tube, the vast majority of molecules are in the bulk and are surrounded by other molecules in an homogeneous environment. As soon as you start to perform reactions in the micrometre sized channels of these devices, molecules see the channel surfaces more frequently and hence the chemistry that is governing the reaction will change. The surface now dominates the processes such as kinetic pathways and reaction pathways. In deMello’s lab, the various facets of a reaction, from sample injection to purification and separation, can all be performed in tiny devices that can then be fitted together in order to allow the complete range of reaction processes to happen sequentially. Some of the primary advantages of performing synthetic chemistry or biology within microfluidic devices include improvements in speed, control, efficiency and throughput with respect to conventional reactors. Importantly, you can extract a lot of information in a short time, and you can control or process reactions in ways you couldn’t on the large scale.

The application of these ideas to nanotechnology is a new direction that this work is taking. Tiny machines for tiny particles - it seems to make perfect sense. The advantages that are gained from small scale reactions for nanotechnology are explained by deMello: ’If you were to try and make cadmium selenide (CdSe) nanoparticles (which you might want to use as a biolabel), and tune the colour of the emission that comes from them, what you need to do is effectively change the particle size. If you have a whole sample where all the nanoparticles have a particular well defined size, that would give you a particular colour. If you like you can design your own pattern for a particular process. To do this using normal synthetic processes is quite difficult.’ Nanoparticles are formed from seed particles and the aim of deMello’s current project is to grow them all at the same rate so they all have the same size. And that’s the bottom line, according to deMello; it’s down to control. If some particles are small and some are big then their optical and electronic properties are going to be broad and mixed. The ideal situation would be to control the growth to such an extent that all the particles in a sample are exactly the same size. Once this is achieved, the spectral purity of the sample will be very well defined and the particles can be used for labels with very well defined physical characteristics. DeMello adds that ’microreactors allow us to really control our reaction conditions so that we’re in the best possible situation to control the growth of these particles’.