Thursday, 25 October 2012

DIY Lab Equipment?

A drill-powered centrifuge, your own personal pharmacy or made to measure prosthetic limbs, 3D printing has come a long way since the fuss about custom chocolate. As this is first and foremost a chemistry blog, how does 3D printing work, and how can it revolutionise chemistry?

So firstly, how do we go about printing in 3D? The cheapest RepRap 3D printer currently retails at £749. This allows users to print with 2 types of plastic, acrylonitrile butadiene styrene (ABS), and Poly(lactic acid) (PLA). Users either download designs from repositories like Thingiverse, or create their own design in 3D software like SketchUp. Many different types of printing are possible, the RepRap using a technique called Fused Deposition Modelling (I think we'll stick with FDM). In FDM, filaments of the desired plastic are wrapped into coils (think 3D ink cartridges), and when required drawn into a nozzle. This nozzle is heated, so the plastic melts. A computer directs the nozzle in 3 dimensions, so the melted plastic is placed exactly where required. Once the plastic is out of the nozzle, it cools and hardens, to form part of the 3D object.

So you've got your printer, stocked up on filament, now what? Well some of the simpler chemistry designs available are for common lab gear like Buchner Funnels. However, if I wanted a plastic Buchner funnel that'll likely dissolve at the first sign of an organic solvent, forking out £749 for a 3D printer wouldn't be my first idea. £749 is enough to keep even me the clumsiest of chemists in Buchner funnels for life. So far then, a 3D printer doesn't look like it's coming to a lab near you any time soon, so what else can it do?

The simplest, genuinely useful piece of lab equipment I've seen (and I'd love to hear about others) is the DremelFuge (video in the first link), for the price of a drill, and a few grams of plastic (I make it about £60), you've got yourself a basic centrifuge capable of speeds up to 33,000rpm - which is getting into "ultracentrifuge" territory. Need a handy centrifuge for field work? Forgotten to balance your lab's centrifuge and written off a £1000 piece of kit? Suddenly the DremelFuge sounds pretty attractive.  Whilst I'm not suggesting selling your bench-top centrifuges and heading down to B&Q, for labs on a budget, hackerspaces for examples, you're opening up avenues that wouldn't previously have been possible without serious funding.

But yes, most labs that need one already have a perfectly good centrifuge, and whilst it shows 3D printing can potentially save costs (especially when you've already taken the initial hit on the printer) its not shown it can truly innovate yet. What about your own personal pharmacy?

That's just what the Chronin group at the University of Glasgow have been doing. Using an adapted 3D printer, they've developed techniques for printing reaction vessels, with the chemicals already inside. By inserting electrodes, they were also able to produce an electrochemical cell. Next (and this is where 3D printing becomes really interesting), they found that the shape of the vessel determines the products formed. As proof of concept, they've used this to synthesise some novel heterocyclic molecules, with the printed reactor vessel an important part of the synthesis.

Finally, their pièce de résistance, is reaction vessels that play an active part in the reaction. By mixing a Pd/C catalyst into the plastic used to fabricate the reaction vessel, the vessel could be used to hydrogenate styrene to ethylbenzene in around 30 minutes at room temperature.

So where's this heading? Cronin's group envision a situation where you combine some biotechnology into this too, and create a one-piece home lab, where you give it some cells, it works out what diseases you're susceptible to, produces a drug to cure it, and all before you've even developed a symptom. We're not quite there yet, but that's something pretty awesome to aspire to.

Sticking with their catalytic vessels, they also suggested using it so patients can make their own drugs at home, from a common starting material. Imagine it like a Rubik's cube. You buy your starting material from the supermarket, and stick it in the top. Each block in the Rubik's cube is impregnated with a different catalyst, so by directing your starting material from square to square, you'd be able to transform it in different ways. I can imagine a situation where you look up a recipe for, say, Bupropion, with instructions like, "twist top of cube to the left, rest on it's right side, then leave in the microwave for 10 minutes".

Give it 10, maybe 15 years and if I was a pharmaceutical company, the DEA (it's not hard to think of some illicit applications, is it?), or, sadly, your friendly departmental glass-blower, this technology would be starting to worry me, because the possibilities for 3D printing really do seem to only be limited by human imagination.

For more on the work of the Cronin group, this BBC video is a nice introduction, the RSC have a decent article here and the groups paper is also available here (if you've got Nature Chemistry access - unbelievably my uni don't). For more on 3D printing, there's a nice article in Science magazine (again, pay-walls, sorry).

As usual, any comments or questions would be much appreciated. If you spot a mistake, or feel I've missed something, let me know. Anyone wondering where the second part of my Sports Drug Doping series has got to, it's coming, I'm still gathering material. There's a follow-up to my Petrol from Carbon Dioxide blog in the pipeline too-when I've found out how many cows are on the planet (all will become clear!).

Monday, 22 October 2012

Chem Coach Carnival: UK Undergraduate

I figured a lot of the contributions to See Arr Oh's Chem Coach Carnival would be about the higher end, amazing jobs you can get through chemistry. Most (all?) of these people would have started their careers as undergraduate chemists, and as I'm a current undergraduate (UK-based), I figured I'd start there, and ask the question:

How do you get onto a chemistry degree program?

If you're currently a high school student (GCSE's)...then firstly well done on having some idea what you want to do with your life! There's not much to worry about right now, but when choosing A-levels, if a teacher tells you "take the subjects you enjoy"-pay absolutely no attention at all. (Note: This is actually decent advice if you have no idea at all, but no good if you've made your mind up) If you know you want to do chemistry, but happen to enjoy History, French and English too, then whatever you do: don't take this combination! Most, if not all, chemistry departments in the UK require at least AS-level Maths, and another science besides Chemistry at A2 (ideally Biology or Physics, preferably both). If you want to study Chemistry, you really must start your A-levels studying Chemistry, Maths, Biology/Physics, and then you can probably get away with a free choice on the last one. 

Besides that, work hard, and don't neglect GCSE English, you'll be in a world of pain if you don't get a C.

If you're currently studying for AS-levels...assuming you've followed the advice above, you're all set to apply to Chemistry at university.* My first advice is that it's never too early to go to open days. Some uni's have open days in June/July, and then again in September. The earlier ones can often be quieter, and it gets your mind thinking about university. Uni's often monitor attendances at open days, so showing an early interest is only going to be a point in your favour. If you can think of a question to ask, ask it, but don't worry about being too shy - most people are. I've given a few open day department tours, and the amount of people who say nothing is crazy high, so don't worry about it.

If you can get any chemistry-related work experience, jump at the opportunity, however mundane it looks; chances are like gold dust, so it'll help your uni application stand out. Other than that, reading around your subject is very important, especially when it comes to interviews (more on those delights below). Seriously, at least read Bad Science at a minimum [If anyone can suggest any others, I'll post a list at the bottom of the page]. Work on your personal statement over the summer, they can be hell to write, and the sooner you get your UCAS application submitted, the better. A lot of uni's offer places on a first-come-first-served basis (assuming you're good enough)

So you've applied....firstly-well done! It’ll be a while before you hear anything, so relax and keep reading.

Aargh - interview! Ok, so I've instantly displayed the wrong emotions, interviews are nothing to be worried about, relax! The academic involved isn't (usually) trying to catch you out; they want to let you show what you know. If you mentioned any extra reading in your personal statement, re-read it before the interview. It's also worth reading a bit ahead in your textbook if you can. Most chemistry syllabus' cover the same material, but in a different order, so don't be too surprised if an academic asks something you haven't learnt yet, they simply don't know you haven't done it. If you can answer, have a go, but it might be worth starting with "So we haven't covered this in class yet but...", to give yourself a margin for error.
Whatever you do, don't try and BS an academic! To my error, I tried this one - learn from my mistake! In my personal statement, I mentioned the toxin Ricin, and the assassination of Georgi Markov. My interviewer asked me how Ricin worked. I couldn't quite remember, but I went for it, and said something that was part-truth, part-guess and part utter tosh. He simply smiled at me and moved on. At the end of the interview, he had a hunt through his bookshelves and dug out a copy of a paper, asking me to read it before my next interview. I sat there in the waiting room, reading a paper written by the interviewer himself, on the precise manner of ricin bioactivity. Needless to say, I didn't get an offer.

Other than that, good luck with getting on the next step to your dream job in chemistry!

Other Books: The Poisoner's Handbook; Copies of New Scientist, Scientific American...;

*If you're looking at this, don't panic if you haven't got the right subject choices, and it's too late to change. Take a look at foundation year courses, or see if your sixth form/college will let you stay on another year so you can take the right subjects. 

Saturday, 20 October 2012

Sports Drug Doping Part 1: What's banned?

In the wake of the recent controversy surrounding Lance Armstrong, and many other high profile cyclists from the 2000's, I thought it might be worth talking about how anti-doping authorities, such as WADA and USADA go about catching drug cheats. This area has been covered in the literature frequently, and this paper provides the basis for this blog, but unfortunately it'll be hidden behind a pay wall from many people. So firstly, what are they testing for?

 Well basically, any substance artificially introduced to the body which provides an advantage to athletes, whether natural or artificial. WADA (the World Anti-Doping Agency), in conjunction with the International Olympic Committee (IOC), have published a list of banned substances and techniques, which outlines the types of drugs banned, with examples of each.

Prohibited Substances:

Athletes are never allowed to test positive for these drugs, with an unexplainable positive usually resulting in a ban. The categories are:

  1. Non-Approved Substances: If a drug hasn't been approved for human use by a government health authority, it can't appear in samples. The is to prevent athletes taking designer drugs, dangerous drugs which have been banned, or drugs only approved for veterinary use. This means drugs which aren't safe for humans (or the safety is unknown) should never be taken by athletes.
  2. Anabolic Agents: Otherwise known as steroids, these are drugs designed to increase the size of muscles faster than is naturally possible. Examples include 1-androstenediol, a potent muscle building enhancer. These drugs mimic the effects of testosterone and other steroid hormones on the body.
  3. Peptide Hormones, Growth Factors and related: Like steroid hormones, these are naturally produced in the body, but are also artificially introduced for a variety of reasons. This category is home to the infamous EPO (Erythropoietin). EPO aids in the delivery of oxygen to muscles, by increasing red blood cell production. This gives a significant increase in VO2 max for the athlete.
  4. Beta-2 Agonists: Many drugs in this category are actually prescribed for asthma, so afflicted athletes are allowed to test positive up to the recommended dose. Although, there is evidence (apologies for the pay wall) that the restrictions may actually hinder asthmatic athletes. These drugs are powerful bronchodilators, helping to open up the lungs (hence their asthma use). When inhaled, the drugs have only a significant impact on the lungs, but when injected or used in tablet form, they may act as anabolic agents, which is why they're banned.
  5. Hormone and Metabolic Regulators: Actually some of these drugs are often used to treat breast cancer (such as Tamoxifen and Anastrozole), but would be taken by elite male athletes to disguise the physical impacts of increased testosterone levels. Abnormally high testosterone in the body is converted to estrogen, leading to gynecomastia (or man-boobs).
  6. Diuretics and masking agents: Anything designed to give an artificially low test result, or increase secretion of drugs from the body, is banned. Infusing saline into the blood stream helps to dilute the blood, giving lowered test results.
Banned Techniques:

In additions to banned drugs, certain techniques are banned too. Reintroducing blood is the technique which has made the most headlines. Athletes have blood removed prior to an event, then reinfuse it at a critical moment, boosting performance. Other banned techniques are introducing artificial oxygen carriers to the blood, or manipulating the composition of blood. Gene Doping, introducing nucleic acid polymers, is banned, as is introducing genetically modified cells. It goes without saying that it's also banned to tamper with samples.

Drugs banned during events:

So the above drugs and techniques are banned at all times, whilst other drugs are only banned during events. These include stimulants (like Caffeine), narcotics (like morphine), Cannabinoids (natural Cannabis or synthetic THC), and glucocorticosteroids (prevent inflammation, helping injury management). In some sports, alcohol and beta-blockers are banned too.

So now we know what's banned, the next question is: "How do we detect them?", and hopefully the next blog will answer that.

Friday, 19 October 2012

Petrol from Carbon Dioxide

A UK company called Air Fuel Synthesis have announced that their demonstration unit on Teeside has successfully produced petrol from carbon dioxide taken from the air. Okay, so the current return of 5 litres of petrol for a cool £1m is hardly forecourt pricing (at the moment), but this is a chemistry blog, so how have they done it?

Well actually, the chemistry, according to their technical review, isn't all that difficult.

Step 1: Mix air with a mist of Sodium Hydroxide solution

Right, as I said, a relatively straightforward start to proceedings. Large quantities of air is blown into a huge tower contain a mist of sodium hydroxide solution (I say a huge tower, they're currently running this business out of a shipping container, but think long-term!). The CO2 in the air reacts with the sodium hydroxide solution:

CO2 + 2NaOH --> NaCO3 + H2O

Anything else in the air, for example Nitrogen, Oxygen and Argon, will pass straight through the tower, leaving a nice puddle of sodium carbonate solution at the bottom of it. As an optional extra, they've suggested condensing water vapour out of the air before blowing it up the tower, as the process needs pure water from somewhere (see step 3).

Step 2: Electrolysis of Sodium Carbonate

Basically, all step 1 does is get the carbon dioxide out of the air, now we need to regenerate it. The simplest way here is to electrolyse the sodium carbonate solution, regenerating the CO2 gas, which can be easily collected and stored.

Step 3: More electrolysis

I mentioned water in step 1, and this is where it's needed. Water is electrolysed to give hydrogen gas. Not a lot else to say about this, if you're not familiar with electrolysis, there's a nice video of it here.

Step 4: Making Syngas

Now you've got CO2 and H2 gas,the reverse-water-gas-shift reaction can be used to produce syn gas:

H2 + CO2 --> CO + H2O

Syn gas can then be used in two ways:

A: A fuel can be made by the Fischer-Tropsch Synthesis, which is already really common industrially (take a look at Sasol). I'm not going to give the equation here, but the important thing is that CO, H2 and a catalyst (probably Cobalt or Iron based in this case), combine at around 150-300oC to give a mixture of linear and branched alkanes and alkenes, probably with the odd oxygen containing functional group (alcohols, aldehydes and ketones) thrown in for good measure. This is the basic fuel, which can then be adjusted to suit needs.

B: Rather than a Fischer-Tropsch route, the Syngas can alternatively be combined to give methanol (CH3OH), itself an important chemical feedstock. The Mobil process then converts methanol to a more recognisable fuel. It basically works by dehydrating (removing water) from the methanol, to leave first a dimethyl ether, and then finally a hydrocarbon fuel.

Where's this technology heading?

Well the company admit themselves that it's early days when it comes to this technology, and they also say they can't see this being a long-term solution to running out of oil. Simply, this process is hugely energy-intensive as it is, so is going to need a really cheap source of electricity to be a viable process. At the moment, they're targeting the motorsport industry as being interested in their fuel. Now beyond F1, my motorsport knowledge isn't great, but the Mclaren and Sauber F1 teams have recently been declared carbon neutral, so may have an interest in this technology in helping to achieve those goals. Also, Lotus Cars have been active with their Exige Tri-Fuel sports car, something Air Fuel Synthesis highlight on their website.

 If Air Fuel Synthesis could find a source of cheap energy (such as off-peak electricity produced by renewables), then that's a start, and then it's all down to how efficient the process is. As you can see, two electrolysis steps, and two energy intensive reactions mean energy costs will be huge, and there's a definite opportunity for new chemistry to innovate a way around this. So good luck to them! It's a nice idea, and great to see a proof of concept, so I'll be keeping an eye out for this in the future.

If you've got anything to say, please leave a comment. Feel free to ask any questions about what I've written, and let me know if you find any faults.

Tuesday, 16 October 2012

Education, Education, Education (and repeat)

So a lot of Chemistry-related blogs recently picked up on this Washington Post piece, "Why are you forcing my son to take chemistry". Other blogs have covered the ground very well, but one comment made by Chemjobber, really struck a cord with me.

Won't someone speak up for the joys of memorization? Very first, I assume that Mr. Bernstein is deeply mistaken about general chemistry being all memorization. Second, does anyone actually teach chemistry by memorization? Third, I've always felt that remembering something was the byproduct of actual understanding of the concept. People don't like memorizing things that are "useless..." - Chemjobber
Well, I realise CJ is based in the USA, but when it comes to a high school/sixth form education in the UK, memorization is king. When I took A-level chemistry not too long ago, memorisation was probably what I spent the most time revising.

For example, we had to learn the colours of transition metal complexes. So take any transition metal, with water, ammonia or hydroxide ligands, and a few years ago, I'd be able to tell you exactly what colour complex you'd get. In the exams, you'd be asked, "What colour is [Ni(OH2)6]2+ ?", and if you didn't know, too bad, that's a mark lost. I knew a girl who took it upon herself to simply paint her fingernails the right colours, she got the marks, I didn't (Not that I'm bitter...). And whilst she might have gone into the exam with funky coloured nails, no invigilator was ever going to suspect that it was the answer to an exam question.

Another example is the shapes of molecules, rather than learning the very simple Valence Shell Electron Pair Repulsion Theory (or VSEPR - for any non-chemists, it's honestly easier to understand than to say) I had to know that BCl3 was trigonal planar, and ammonia was trigonal pyramidal "because it is" - what use is that to anyone?

It's a trend throughout high school education, the phrase 'jumping through hoops' is often used, and it sums the situation up brilliantly. The exam boards publish a specification with a very precise list of things you need to know, you go away and learn them, and you get a good grade. At no point in the process is your understanding truly tested. I walked away with an A grade in A-level chemistry, but knowing a list of facts, and few translatable skills.