All along this year, we have been working in the problematic of how to measure almost any kind of protein with an automated device. We are willing to present our device to this award because we hope that you could see the potentiality of our system in the way in which we see it.
For solving this challenge we have developed two different measuring systems:
The optics approach
For our first approach, we have built, characterized and documented a microfluidic colorimeter, capable of measuring total protein concentration at 280 nm. We have designed all the parts included in the system:
A laser-cut structure.
A microfluidic chip which brings microliters of the sample to the measurement chamber. It handles two experiments at the same time.
An electronic PCBs capable of measure 4 microfluidics chambers at the same time.
A cassette, which carries the microfluidic chip inside it, surrounded by two methacrylate slides with the optic modules housing.
We have also characterized the system with real protein concentrations (BSA), and modeled the system dependence under the change of different variables (time, the temperature of the led…):
If you want to know more about the system, check our First Prototype page:First Prototype
The electrochemical approach
We have realized that even if we accomplish a commercial Nanodrop sensibility, we are not going to measure accurately the concentration of our protein at the levels that we find in the environment.
So we have developed a completely new system, integrating aptamers for bringing the specificity of our target protein to our measures.
Before explaining the system and showing the results, we want to share with you our vision of why the aptamers are going to revolutionize the world of the organic measurements.
Aptamers are artificial engineered ADN (or ARN) strands capable of join specifically to almost any kind of molecule big enough for having epitopes. They are the alternative to antibodies which involve several improvements like the non-use of animals in their production, the more affordability or the more stability at higher temperatures.Aptamers
Aptamers have a high potential to revolutionize the world of chemical measurements. The only reason why we did not find them in the previous iGEM years, is that there is not an easy, well documented and affordable system of discovery and measuring with them.
This is what we have solved with the following results:
We have integrated the aptamers into a Cyclic Voltammetry measurement workflow. In this way, we have achieved quantification of 1.33 uM, integrating the gold standard of aptamers (the one for thrombin) in our system and measuring thrombin concentration.
We have developed our final device: a complete system for measuring in an automated way any kind of protein concentration. It only has the requirement of developing an electrode for this protein.
We have described a simple universal protocol for integrating any kind of aptamer in our electrodes. It cost less than 20€ so it is at hand for any future iGEM teams that want to work with aptamers.
For the first time in iGEM, we have accomplished the first successful aptamer discovery method. We have also described a quantitative aptamer characterization method and a way to improve them computationally.
With this methods we are not just bringing the aptamer measurement to iGEM, we bring a way in which future iGEMmers could integrate almost any kind of molecule to its measurements.
Once this protocol has been described, we hope that we will see in the next years the aptamer’s registry page getting larger and larger.