Special, highly porous gels prepared by Petr Slavík in the group of Professor David K. Smith at University of York, UK, have unique properties – they can be used as carrier substances for very small metal particles which can in turn come in useful in cross-coupling reactions of major importance in the pharmaceutical sector. “Theoretically we could use these gels to prepare drugs in an easy and cheap manner without leaving almost any traces of the used catalyst. The second possible use is cleaning of waste compounds in the pharmaceutical sector that also contain large amounts of transition metals,” explains our last year’s grant recipient Petr Slavík.
The purpose of your research is to prepare highly porous gels; what are they and what is the preparation process like?
In my research I seek to prepare gels on the basis of dibenzylidene sorbitol that are able to react with different precious metals (gold, platinum, palladium etc.) in aqueous environment and then incorporate them in the gel itself. Sorbitol-based agents (sorbitol is a common sugar alcohol) can gradually self-assemble into larger wholes through non-covalent interactions and, at the same time, they can also bind large amounts of solvents (water in this case) into their structure. They are very easy to prepare. We mix these agents with water, dissolve them and then after they are cooled down or are otherwise physically stimulated we obtain a gel whose properties combine those of a solid and a liquid. It works on the principle similar to that of making Jell-O at home.
Prepared gels and metal nanoparticles are tested as catalysts for cross-coupling reactions in aqueous environment. What does such testing look like?
Having been saturated with palladium solution, the gel can absorb a certain amount of metal from its surroundings which is trapped inside the gel. Then, as in any other organic synthesis, I combine the ingredients with a solvent, I add the gel (the catalyst) and watch the course of the reactions under the tested conditions. In contrast to reaction conditions that are commonly used for these reactions (i.e. an inert atmosphere and anhydrous environment), my reactions can occur without the need of using an inert atmosphere and in water as a reaction medium.
Contamination of products by transition metals is eliminated during the reaction, how is it possible?
The transition metal is incorporated directly in the gel structure. Most sizes of palladium nanoparticles range from 5 to 20 nanometres, while the pores in the gel are smaller. Consequently, palladium has no chance to escape from the gel. While the pores are big enough for ordinary organic molecules used in the pharmaceutical sector to pass through freely, palladium cannot.
The advantage of the tested catalysts is that they can be prepared in an easy and cheap manner. Where can one easily get cheap precious metals?
Some of my predecessors explored how to obtain these agents from, for instance, waste water. I have been to a conference recently dedicated to this topic. They said there that a lot of materials can be obtained from e-waste (mobile phone and computer waste), or from mining residuals. So far, all of this is purely theoretical. I prepare my catalysts using common, commercially available resources.
Yet another advantage of these catalysts is that they are recyclable…
Yes they can be very easily recycled. Apart from sorbitol as I have already mentioned, our gels contain agarose, a sugar which enhances the mechanical properties. This means that we can treat these gels practically just like solids. When the reaction is over, I simply take the gel out, wash it and can use it in another reaction. This process is much easier than using finely dispersed powders – the usual form of these metals.
What can your discovery bring to the pharmaceutical industry?
Anything made in the pharmaceutical sector is subject to very strict regulations of residual impurities in drugs, which is also the case of transition metals for instance. In case of palladium, the concentration must be less than 10 ppm (10 particles per 1,000,000 particles), which is quite a low value and it is difficult to achieve it without additional cleaning. Our gels could theoretically help produce drugs where additional cleaning processes would not be necessary.
Could your discoveries be applied in other fields?
Yes, of course. The second possible use is cleaning of waste compounds in the pharmaceutical sector that also contain large amounts of transition metals. There are also other possibilities of cleaning in this area but the great advantage of our gels is that they are very cheap and can be produced from commonly available natural raw materials and then used as catalysts for instance.
Why have you personally specialised in this area of chemistry?
I have been focusing on the supramolecular chemistry from my bachelor’s studies until I completed the doctoral programme. When I was making up my mind where to go on my post-doctoral research stay, I wanted to keep doing research in this field but I also wanted to change the specialisation at least a little bit.
Thanks to the Experientia Foundation grant you now work in the group of Professor David K. Smith at University of York, UK. Why did you find Professor Smith’s research appealing?
There were more factors that played a major role. For one thing I wanted to go to an English speaking country to improve my English. I also did not want to join a big group of a Nobel Prize winner whom I would not have much chance to see. We are about eight researchers in the group of Professor Smith, it is rather a small and consistent group and we meet on a very regular basis. Last but not least, it was the research itself which I found very interesting and very useful. Professor Smith is a promoter of science at University of York, he regularly posts tweets about his research on Twitter and publishes videos on YouTube. The way he promotes his own research appealed to me, too.
So what does the research team of Professor Smith work on?
There are quite a lot of topics that the research group of Professor Smith works on. Although we are a small group, almost everyone has their own project; all projects have gel research in common. For example one part of the group uses gels that are modified to be softer in certain places and harder in others. Then they grow tissue cultures on these modified gels in cooperation with the biology department. In future, this method could help create parts of bones or new organs. Another colleague of mine conducts research in the area of arsenic removal from waste water, a topic of great concern today. Waste water is contaminated with arsenic on a large scale and it can have very serious negative health effects.
It looks that the group of Professor Smith focuses strongly on the application of the basic research…
Yes, Professor Smith feels very strongly about the higher purpose in what we do in our research and wants every single one of us (even a bachelor student completing his degree in our group) to feel this way, too. For example my colleague who is trying to remove arsenic from water knows that if his research works the next phase of the project will be cooperation with Bangladesh, a country with perhaps the highest level of arsenic water contamination in the world, where it could be extremely useful.
What is the higher purpose in your case?
If my research works we would most probably start cooperation with pharmaceutical companies and offer them to test the gels I will have prepared.
What have you learned from Professor Smith during your research stay so far?
Professor Smith is very hard-working. I have not met him so many times during my stay because he is very busy. I admire his ability to delegate smaller tasks to other people, including students, in order to have more time to write articles, reviews and to conduct the research. In terms of science, I have learned to prepare gels, examine their properties and use them in further research.
What has been your impression of University of York so far? How is the English scientific community different from the Czech one?
One of the first things I noticed was the university environment. The campus is situated around the lake and the town of York is really splendid, too. What surprised me from a technical point of view is that compared to Czech universities the standard of laboratory supplies is lower – we sometimes do not have all the laboratory glassware or chemicals that we need. It is a paradox because they have state-of-the-art technological equipment here. They also have much stricter security measures here. The moment I want to carry out a new reaction I need to fill in a rather detailed security risk form about all the things that can happen or whom to contact if they find out that something went wrong in the lab at night. What I appreciate, on the other hand, is that we have a common kitchen and dining room right on our floor where all the department meets during the lunch break and can discuss various topics. I missed that in Czech institutions.
What was the goal of your research stay?
I wanted to learn something new, that’s also why I changed the topic of my research. I would also like to learn from Professor Smith what it takes to lead a research group and to promote research – for one thing to help instil in students why they do their research and make them proud of what they do, and for another to be able to explain it to the wider public. I find this very important today. Naturally, I would be happy if I managed to publish the results of my research or start cooperation with the pharmaceutical sector.
Many of your predecessors decided to extend their stay abroad. What are your plans for the future?
I have already applied for another grant. If my bid is successful, I will extend my stay until 2020. If not I would return back to the Czech Republic.
Can you tell us in conclusion what the Experientia Foundation grant has meant for you personally and what progress you have made so far in your career thanks to your research stay?
The possibility to gain experience abroad and not having to pay all the stay alone has been an immense contribution. The grant also made it possible for my wife to come stay with me. I also hope to gain experience to use in my future career and in applying for next grants.
What message would you like to give to prospective applicants for the Experientia Foundation grant?
To try and go for it, the chances of getting the grant are quite high. Besides, when I was looking for different grant applications the Experientia Foundation grant seemed like the less complicated grant application in the Czech Republic. It only has three pages of text while other grant applications can have as many as 40 pages. And what is more, the applicant learns about the result quite soon.
born in Třebíč in 1989. In 2017, he earned his PhD degree in organic chemistry at University of Chemistry and Technology in Prague under the supervision of Professor Pavel Lhoták. Currently, he is at the post-doctoral research stay at University of York, UK, with the support of a one-year grant of CZK 760,000 from the Experientia Foundation.