Buying the best DNA Electrophoresis Tanks for Schools in the UK
We have been asked many times, whilst delivering events, which equipment we use and why. Recently, we have been contacted numerous times by teachers facing the introduction of DNA Electrophoresis into their teaching of new Scottish Highers in particular.
As far as I know, there exists no specialist guide to help inform your decision whether you are based in a school in Scotland, England or Wales. So here are my thoughts – based on my experience from over a decade of keeping my finger on the DNA Electrophoresis tank pulse.
What Makes A Good DNA Electrophoresis Tank For Educational Use in the School Lab?
If it is your first time buying in specialist electrophoresis equipment for your school – it can almost be as arduous a process as researching the best car to buy! With different manufacturers highlighting a range of very similar sounding features – what should you look for? (Especially when there seems a marked difference in price).
When we first started to introduce biotechnology into our event programmes – DNA electrophoresis in particular – we thoroughly researched and tested the leading ranges at the time (including BioRad, Edvotek and NeoScience) and continue to do so. We need to ensure our events raise the benchmark in quality and offer genuinely beneficial training options to science teachers.
We were specifically looking for DNA tanks robust enough to use time and time again in school lab conditions. They had to be reliable, easy to use and quick to clean for our presenters. They also needed to be well supported by consumable DNA lab kits and prove to be cost effective – both initially and in the long run. Most importantly, they had to be able to run DNA gels as quickly and accurately as possible – to fit in with lesson times.
Do these considerations ring any bells?
The Little Things To Look For In Good DNA Electrophoresis Tanks and Gel-Trays
- Quality of Power Fittings
- Gel-Tray housing design
- Gel-Tray Closure System
Power Fittings:
When we looked in more depth at the practicality of each design – we made sure to look at the quality of the power fittings and the way they were insulated. (Best not to shock the user unwittingly – whether it was the first or hundredth time of use).
Platinum electrodes are fairly standard, to avoid corrosion and rusting over time, but the quality of the fitment to the tank was a concern for us having heard stories of these ‘snapping’ off some of the models available. It was actually quite easy to see and feel the difference in quality of the materials used in the tanks – and it is not necessarily the most expensive that had the best solution.
Look for a injection moulded UV transparent base – as it prevents leakage and breakage whilst offering greatest versatility – but also check that the electrode connectors are recessed in the main body of the unit too. It makes for the strongest, most secure and easiest ‘safety-lid’ fitment that has fewest weak points.
The repetitive closure and removal of the safety lid and the tank’s attachment to the power supply make these the most important design features to look at – as these are the parts of the tank that will wear most quickly. At the end of the day, it’s what effects the cost considerations most – because if you get it wrong you will be replacing the unit in no time at all.
It’s also worth checking the quality of the connection leads themselves – and whether or not they too are recessed or exposed. If you can see metal – it may be worth avoiding it! Durable, well insulated connectors – making the tank safest too use and most resistant to ‘wire-fraying’ – are going to last longer.
Power Supplies:
Whilst on the subject of power – we ended up looking at an even larger array of power supply units designed for DNA Electrophoresis than tanks. More buttons, more display options and a bigger headache! At the end of the day – you want as much power to be delivered as safely as possible in an easily controllable way to ensure the DNA gels run quickly but accurately. It is possible to mix and match tank and supply – but it takes more time and you can never be 100% sure it will work to its optimum with your chosen tank if it wasn’t designed specifically for it.
We decided on the TetraSource™ 300 Power Supply – capable of running 2 double-gel tank units or 2 six-gel tank units in 25-30 minutes. I still use the original unit purchased in 2007 and it has never let me down yet. (I do have have a brand new shiny updated model sitting in a box just in case – awaiting an opportunity to get into the action – but it has not yet happened in over 1500 events).
Just beware – anything less than 150V is probably not going to run DNA gels within a single lesson – let alone allow time for result analysis – no matter what the salesperson tells you. A 150V unit can run a double gel tank and even a single six gel tank if that’s what you decide to go for (but it does take 35-40 mins on the latter in our experience).
Gel-Tray Design:
The way in which gel trays fit into the tank is also important – especially if there is the ability to place more than one in the tank at a time (which is an additional consideration you will need to make before purchasing your new equipment). Again, you need a simple, robust housing system – a slot and slide is easy to use and doesn’t run the risk of snapping off a locking arm that we have seen used.
The Gel-Trays themselves should also be looked at closely. Typically, you will get the tray(s) with the tank – so choose something hard-wearing, that will not run the chance of leakage later down the line, but easy enough for students to use themselves. Some systems we looked at seemed very sleek – only to prove difficult to clean, which led to leaking agarose all over the desk.
Even worse, some of the ‘pull-up’ barrier type designs we tested ripped the gels that had taken 10+ minutes to set. The simplest solution – that we still use in every DNA Electrophoresis session – proved to be the slot into ‘dam’ that replaced the old style tape- over-the-tray-end. These heavy duty dams stop the leakage and do not run the risk of warping either. A number of gel-trays use this simple idea.
The best gel trays have an embossed gel ruler to one side – making loading and analysis that little bit easier.
The Practical Decisions To Make
First off – stand back from the glossy pictures, the demo models and the sales bumpff and make sure you know who is going to be using the system, for what purpose and how frequently.
We wanted total control over the power supply and tank for KS3 & KS4 pupils. (It enables students to focus on the fine skills of working with a DNA gel but didn’t risk accident or breakage of the more expensive system elements). We decided on an option provided by Edvotek that enables six gel trays to run in one larger tank. At the time – the tanks had adjustable feet to account for any uneven surfaces (as do a number of designs) but these have thankfully been replaced by fixed feet making it easier to set up – so long as you don’t carry out the experiment on gravel!
I have to say – their Hexagel Unit ticks all the right boxes for us – so long as you are happy for your student groups to ‘dry load’ their samples. In this instance, students load samples at their desk and transport the tray to the experiment desk holding the power supply and gel tank. The teacher mixes a bulk load (1 litre) of buffer and pours it slowly into both depressed ends of the tank to ensure even coverage and minimise wash out. It’s quick and effective but most importantly, it allows time for students to analysis the results achieved. Furthermore, it costs a fraction of the price of buying a single-gel electrophoresis tank for each student pair or group.
The system works well with A’level, BTEC L3 or Higher students too – but we do like the option of offering the opportunity for the student teams/pairs to be in control of the complete activity. For this age range – a double gel tank is probably the best idea – allowing for greater flexibility than a single-gel tank but just as economical on chemicals and power consumption (meaning cheaper 150V units can be purchased).
Cost vs Performance?
Single and Double Gel Tanks are where the biggest range of options exist – with a number of similar designs. We were interested in whether or not the difference in costs were noticeable in quality and performance. Some of the DNA Electrophoresis Tanks for schools (and not always the cheapest) were a little fragile around the power connection sockets mentioned earlier (one even snapped in half when the power connector was carefully removed).
Look very carefully at the quality of the plastics used around the socket – but I know it can be hard to predict how it will function over time without testing it out time and time again. (It’s one of the ways we are fortunate – we get to run the same equipment lots of times in a relatively short period). In the end – we found some of the highest price tags were not justified in the terms of our tests and it did feel as if you were paying the Brand Name premium.
As you may have guessed, we found the best overall package with Edvotek manufactured DNA Electrophoresis Tanks – in the end. A mid-cost system. They were not the first system we used – and we spent a painful year hoping the alternative system we purchased would work reliably whilst paying over the odds for the chemical kits designed for the tanks we had purchased. We were new at buying this kind of equipment and I equate it to the first car I ever bought (a top of the range but old – Rover Metro!). I didn’t know what to look for then and it seems I continue to learn best by painful experience!
I hope my learning curve helps with your decisions.
Don’t take my word for it – look at different tanks for yourself – with an eye on the pointers above. I will say that the chemical consumables seem to be where the profits are made – so look at how many gels you can load with the DNA kits. Again, we went with Edvotek – but we only use half the recommended volumes of simulated DNA samples in the DYE kits and we are very happy with the results. But that is a different story.
Problems in DNA Gel Tank Paradise
Unfortunately, Edvotek Europe closed its doors a couple of years ago – and we, like many others, were in a bit of a quandary as to how to best continue buying the equipment. Edvotek US have since formed partnerships with a number of suppliers in the UK and also sell directly to UK customers.
We use it so much that we were delighted to become one of the UK suppliers. But, therein lies the problem. Now that we do supply the Edvotek equipment – does it cast a shadow of doubt on the advice offered for choosing the right kit for your school?
All I can say is, that if you do visit our online shop you will see we only sell a small range of of very carefully selected resources. These are all based on our experiences during our event programmes. We do not have sales people – our events demonstrate a range of equipment in use – and we aim to maintain our enviable record of 100% recommendation. To do this, we only sell the equipment we totally believe in and have found works well time and time again in typical usage in schools.
Our business is the provision of specialist STEM and G&T Events. We hope our specialist shop helps you avoid the error I made with my first car. It is why we make select resources available. Visit the store and decide for yourself.
www.thethinksomemorestore.co.uk
Written by Matthew Hackett, February 2015