A new look

Welcome to the new-look Sceptical Chymist! Of course, if you’re just reading this in your RSS reader, then things will look pretty familiar (unless you’re logging on to Google Reader for the first time in a few months — but then you probably can’t see through the tears of frustration you’re weeping).

All the other nature.com blogs are having a re-vamp, meaning this will be cross-posted here and there, so we’ve been asked to do a post to introduce the blog to any new readers. Regular readers may even learn something too — or you can skip the next two paragraphs to see what’s new!

We’ve been blogging at the Sceptical Chymist since March 2006 — the first post even handily explained the name (it’s from the book written by Robert Boyle in 1661, which is a useful point to consider as when chemistry started emerging from alchemy;). It started out with contributions from editors from Nature, Nature Chemical Biology and Nature Nanotechnology, but has since evolved to mainly us, the editors of Nature Chemistry — which was just a twinkle in a publisher’s eye back in 2006! Since then, it’s been a great way to communicate with readers less formally than in an editorial or other journal article, plus a wonderful means of generating discussion and receiving feedback.

You can expect to read interviews with chemists around the world in our Reactions series, reports from conferences we attend, ‘edited highlights’ of editorials and In Your Element, our monthly Blogroll column, as well as the occasional post inspired by almost anything. We also have a brave cadre of guest columnists: our two current guests are both graduate students negotiating the academic maze.

That’s the old blog; what’s new? Well, apart from lots of behind-the-scenes improvements that will make blogging much easier for us, you can see that it’s more seamlessly incorporated in the Nature Chemistry website. The side navigation is a bit less cluttered too. Hopefully the main improvement will be in the commenting: now, once your first comment has been approved, your subsequent ones will go live immediately. This should make discussions a bit more dynamic, and remove the wait while we fish every single comment (including our own!) out of the spam filter.

So have a look round, make yourself at home, test out the comments and let us know what you think!

The Nature Chemistry team.

2011 Fall MRS: Stiff storage

Posted on behalf of Rosamund Daw (Senior Editor, Nature)


What technological innovations will form the car of the future? Carbon fibre composites are increasingly a viable option for the structural components of next-generation cars for improved energy efficiency, particularly as their use in the aerospace industry will undoubtedly bring manufacturing costs down. Energy storage devices such as capacitors and batteries will also be the order of the day.

Milo Shaffer and colleagues at Imperial College have recognised this as an opportunity for further energy savings. Both structural re-inforcement composites and electrochemical devices rely on the use of layered architectures. So why not combine the two and incorporate energy storage into the composites which provide strength and stiffness in the body of the car? This imaginative concept, potentially offering huge weight saving was presented in the ‘Applications of Hierarchical Materials’ session at the MRS [Hierarchical composite materials for structural energy; Shaffer, M., Qian, H., Houlle, M., Amadou, J., Bismarck, A., Greenhalgh, E.; Symposium G; 2011 Fall MRS]. I think it offers a refreshingly different angle on the vast research activity going on in energy storage.

Shaffer chose supercapacitor devices which cannot store as much energy as batteries but can quickly discharge; he envisages initial applications in load levelling, rather than providing a comprehensive mobile energy supply. His group approached the problem by modifying the traditional components of composites: carbon fibre laminates act as the electrodes and the epoxy matrix of the material forms the electrolyte. Glass fibre mats acted as insulator layers. The carbon fibre laminates were activated (made porous) to maximise surface area and an ionic liquid was incorporated into the epoxy to improve ionic conductivity. Carbon nanotubes deposited on the carbon fibres simultaneously increased the surface area for further charge storage capability and interlocked with the matrix to constrain buckling — frequently a problem with composites.

Early experiments have confirmed proof of principle. In fact the stiffness of the material is impressive despite the modifications: ‘as good as it gets’ says Shaffer. But there is still some way to go to improve mechanical strength and charge storage capability. Shaffer has partnered with Volvo in an FP7 programme entitled ‘StorAGE’ in which his team has been set the task of achieving 15% of a car’s weight reduction using these multifunctional composites. The first car component to be generated will be the wheel well.

These materials could presumably be more broadly used in smaller scale mobile applications such as laptops where weight and volume are at a premium.

2011 Fall MRS: A plug for stem cells

Posted on behalf of Rosamund Daw (Senior Editor, Nature)


In the field of materials science as applied to regenerative medicine, a common theme is the design of novel scaffold materials as supports for stem cell growth and differentiation. However not all stem cell therapies use scaffolds. In some biomedical research efforts, cells are injected directly into the site of need. Such a strategy has been applied to a variety of different injuries and diseases, for example Parkinson’s disease, stroke, heart attack and spinal-cord injuries. Though the approach has had some successes, a major stumbling block has been simply the ability to deliver a payload of viable cells to the site. Sarah Heilshorn at Stanford University has been investigating how materials science can help and presented her group’s findings in the ‘Biomaterials for Tissue Regeneration’ Symposium at the Fall MRS [The design of hydrogel cell carriers to improve stem cell viability during transplantation by direct injection; Brian Aguado, Sarah Heilshorn; Symposium KK; 2011 MRS Fall Meeting].

Early in vitro model experiments surprisingly revealed that the cell injection procedure itself led to severe membrane damage and around 40% cell death. Heilshorn suggested that this cell death was the result of elongational flow at the entrance of the syringe needle, disrupting cell membranes. Her research group has been investigating how hydrogels can mechanically protect cells from damage during injection. In particular they have focused on physically-crosslinked protein hydrogels. The physical crosslinks are easily broken on the application of shear, and it is this which Heilshorn believes helps protect the cells. The hydrogel shear thins at the walls of the syringe during injection providing lubrication to allow the rest of the gel to flow as a plug through the needle rather than with the differential flows across the bore experienced by a fluid which causes the extensive cell death.

Ingeniously, the material is comprised of two components and gelation occurs on mixing. This obviates the need for one of the usual gelation ‘triggers’ such as a temperature or pH, required in a single component gel, which can also damage the cells.

Heilshorn’s group have demonstrated that human adipocyte-derived stem cells and mouse adipocyte-derived stem cells can happily proliferate and differentiate inside the hydrogels. Furthermore the hydrogels improve the retention of cells injected into a mouse model, compared to delivery in alginate, saline or collagen. Adipocyte- or fat-derived stem cells are easily harvested from patients and are likely to be one of the first stem cell types to be used routinely in the clinic.

I shall look forward to the next chapter in the story, to find out if the hydrogels offer enhanced therapeutic capability.

Reactions – Dave Winkler

Dave Winkler is at CSIRO Materials Science & Engineering in Clayton, Australia, and works on theoretical and computational chemistry and complex systems science.

1. What made you want to be a chemist?

I was always fascinated with how things worked, deciphering their components and interactions that produce an emergent system behaviour or property. I had a home chemistry lab behind the garage when I was young.

2. If you weren’t a chemist and could do any other job, what would it be – and why?

Tough choice, but probably a psychoanalyst or medical specialist. The human body, particularly the human mind, is so incredibly complex there are more than enough great problems for study for the foreseeable future.

3. What are you working on now, and where do you hope it will lead?

Two main areas: understanding the molecular basis for control of stem cell fate and design of small molecules that achieve this; modelling the properties (especially biological effects) of nanomaterials and materials more generally to allow design, optimization and safety.

4. Which historical figure would you most like to have dinner with – and why?

Having read Bill Bryson’s A Short History of Nearly Everything I realise that some of the scientific greats may not have been good dinner conversationalists. I would choose Leonardo da Vinci because of his brilliant mind a breadth of his scientific and artistic interests.

5. When was the last time you did an experiment in the lab – and what was it?

I do computational experiments every day. The last time I was in an experimental lab was to learn to culture embryonic stem cells, about four years ago.

6. If exiled on a desert island, what one book and one music album would you take with you?

Excluding obvious must have books like the Bible, I would choose Caravans by James A Mitchener (one of the great travel sagas), or collected works of Tolstoy. For music either a great blues compilation, or Mozart.

7. Which chemist would you like to see interviewed on Reactions – and why?

George Whitesides, I love the way he thinks so laterally, and the broad range of areas of chemistry he has contributed to.

Fall MRS Meeting 2011: Analogies, highlights and trivia

I’ve spent the last week in, as Ros Daw described on Wednesday, a relatively balmy Boston, mooching around the halls of the Hynes Convention Center and the Sheraton diving in to whichever session of the Materials Research Society meeting took my fancy. Unfortunately, there’s now a very cold bite to the air in New England but thankfully I’m on my way home to the Old England.

It was my first MRS meeting but, being a bit of an ACS meeting veteran, I was expecting something very similar to that but smaller, like an MRS slider to the ACS Big Mac, if you will. And that’s exactly what I found: you have a convention center with lots of parallel sessions, a nearby hotel housing some more sessions, and an Exhibition Hall with lots of people trying to sell stuff. But (dropping the burger analogy for a scientific one), like the nanomaterials discussed in many of the sessions this week, because of confinement effects, the properties of a meeting are not linearly related to their size.

With a smaller meeting (6000 attendees rather than >10,000 seen at ACS meetings) comes the benefit of a smaller meeting space, which leads to a much more ‘intimate’ event. Intimate is probably not the right word with 6000 people involved but if you know someone here then you’re very likely to see them, which in my experience is not how something of the size of the ACS meeting works. It also makes it far easier to go to numerous sessions on a given morning or afternoon, which, given the diverse interests of academics these days, is a big benefit. So I think that this is a perfectly-sized meeting and I gather from the attendees that I met, who keep coming back, that they do too.

There have been a few highlights for me over the week. The symposium on ‘Organic photovoltaic devices’ was my default pick for whenever I was unsure where to go, I was always likely to find something to hold my interest there.

During the meeting, Z.L. Wang (Georgia Tech) received a MRS medal for his work on ZnO nanomaterials, and therefore gave an associated presentation. The goal of much of his ZnO nanowire research is to harvest mechanical energy. Therefore when we do stuff — walk around, work out, move our fingers to play sports games on Xbox — those movements could be used to generate enough power to charge your iPhone or any other portable device. The nanowires are piezoelectric; that is, they generate a voltage when they are bent, and Wang has been working towards improving their efficiency to make them viable for various industrial applications.

This week I saw another take on the same problem when Tom Krupenkin from the University of Wisconsin-Madison discussed his recent work (published in Nature Communications) on using ‘reverse electrowetting’ to harvest energy. At this point I was going to give you a lovely description of how it works, but it seems Katharine Sanderson has already done it over at Nature News. So very briefly, a conductive liquid, if placed on an electrode, can be deformed by charging the electrode surface. This improves the electrode’s wettability and allows the droplet to spread out better. This can also be done in reverse: if you are able to physically deform a droplet on the surface of an electrode (by movement), you can create a charge and thus power. Krupenkin was able to apply this principal to an array of 150 droplets and talked about the possibility of placing such generators in to the heels of shoes. It was a nice talk and I recommend reading more at Nature News and Nature Communications.

I also enjoyed the presentation given by Paul Alivisatos very much. His talk was to celebrate his Von Hippel Award, the highest honour at the MRS society and was nicely balanced between anecdote and cutting-edge science. As a student at the turn of the century working on a completely different topic, I wasn’t particularly aware of the synthetic work of Alivisatos, but that soon changed when I started working for the Journal of Materials Chemistry at the Royal Society of Chemistry; every other paper I read involved the synthesis of nanoparticles, with chemists showing how it was possible to control their size or shape. Given that that was my introduction to the field and that now you can dial up many different structures and sizes, it was nice to go back to the beginning and hear a few tales from when it wasn’t quite so easy (Alivisatos was actually warned off working with them by a theorist colleague!).

And so my one bit of chemistry trivia to give you all comes from Alivisatos. So you know those ‘nanocrystal molecules’ that Alivisatos and his colleagues made by joining nanoparticles together using DNA links? You know whose idea the DNA was? No? Well it was Stanley Miller, of origin of life/amino acid fame! Alivisatos was asked to give a talk by UC Irvine students with the theme “what would you like to be able to do but can’t”. He mentioned the idea of linking nanoparticles together and that they were working on some organic compounds to do just that. Miller was in the audience and apparently put his hand up and said they should try DNA, the rest, as they say, is history. I just looked at the Letter in Nature and there is indeed an acknowledgment to S. Miller.

It might be a little too soon for me to go to the San Fran MRS meeting next Spring but I’ll certainly be thinking about returning next Fall.

Gavin

Gavin Armstrong

Senior Editor

Nature Chemistry