The golden electricity of jodelland:a story about small electrodes, golden nanoparticles and raclette

Hi Everyone,

Im Lucky, Lucky because I am able, yet again, to turn this blog into some kind of a travel story.  Yep I guess the title gave me away…. I am on secondment in Switserland 🙂

Switserland, the land of mountains, cheese, clocks and, so i recently learned, cool screenprinted electrodes which could, in theory, be an alternative to the optical techniques I have been developing at queens. So let me introduce those little swiss wonders to you in a nutshell:

Screenprinted electrodes, or SPEs, are small electrodes (about 4 by 2 by 0.1 centimeter) which you can make yourself. They are basically printed using a printer that looks a bit like one of those old newspaper printing machines. It has a rubber squichie, and a mesh. U cover the mesh with ink, the squichie smears it over the mesh and voila, down on a plastic sheet you get the electrode. One has to print in layers and dry inbetween. So first you use a silver ink. That are the electrode contacts. 3 electrodes are needed to measure, a counter, a working electrode (to apply potential over the system and or measure the current through your system) and a reference electrode (to compare what is happening in your system with a reference). After this layer one ads a layer of graphite ink which can later be functionalised with antibody for example, to go and measure a specific target. Here we are trying something special for which i wil just give a small teaser: Its a new, in house created, ink formula with some of my previously prepared nanoparticles and another, very cheap, carbon based material inside… We expect that this system will allow to get better signal since gold can increase the surface area and, hopefully, the electric catalytic activity thus leading to higher signal while keeping cost at minimal. but more on that later. now lets stick to the basics, So after the layer of graphite you dry and then you smear a layer of dielectric (isolating) ink over the most part of the electrode to isolate the individual electrodes properly from the environment and eachother (we dont want short circuits). Once this is done you obtain something that looks like what you see hereunder.

SPE pic

Figure 1: a screen printed electrode in approximately real size.

Please take a look at the working electrode (WE), because thats where the magic happens 🙂  On that tiny circle we will immobilize a marine biotoxin. Then, simply put, the WE will be inserted into a shellfish extract while the other end is connected to a small potentiostat (a sensor about the size of your palm). Now add to this mixture some antibodys that recognise the toxin (DA-MAB) and some antibodies that recognise that antibody (anti-DA-MAB). In such a mixture some DA-MAB will bind to the WE. However, if there was toxin in the shellfish extract, less DA-MAB will bind to WE since much of the DA-MAB will already have bound to the toxin inside the extract…. now take the electrode out of the mix and wash… (we dont want antibody sticking there by chance but only if its really bound to the toxin on the WE.) If there was no toxin (or very little) in the shellfish you will now have DA-MAB bound to the toxin on the WE and anti-DA-MAB bound to DA-MAB. this anti-DA-MAB has an enzyme on it. That enzyme can catalyse a redox reaction of a substrate. which then creates electons…. and ofcourse electrons mean current. Thus, if there was no toxin in the sample we can generate current on that little electrode which we can measure with the potentiostat… and : Bob’s your uncle…

nouja, maybe it is a little less straightforward than that… but in anycase thats the rough principle. So now i am trying to put this thing together with the help of Davide and Safiye, the real electochemistry experts. I have just started on this project, which will take another 2 months, so no real results yet, but i am hopefull for the next blog….

Apart from these exciting new experiments I want to say a quick word or 2 about Jodelland itself…. It is truly wonderful 🙂

There is:

1) good cheese (ooooo the racelette and fondu)

2) good wine

3) good but very expensive meat (i am temporarily becoming veterinarian)

4) and, most importantly, good bread! Yes i know you would ask yourself dont you have good bread everywhere? Well come to ireland and find it out 🙂

finally, 5) there are beautiful mountains, lakes and so on. making this an endless playground for me, and my wife and son, who joined me here to explore the mountains together in the weekend. And thats what we did last weekend and intend to do again the next and the next…

 

mountain.PNG

Figure 2: The rein gorge from up, with vivi and sparrow. So happy they joined me in this adventure

 

Alright. That was it for today. I must keep this blog short because i am simply to excited to continue my experiments here to continue to write 🙂

Thanks for reading my blog and the best to you all

 

JODELAAAAAA HIPPIE

 

Jordi

 

 

 

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