Biomedical, Other

Fitting a whole molecular biology lab on a single chip.

I never understood microfluidic devices fully. They seemed very complex and while in theory their design seemed simple, i could never get any experience in making one by myself as an undergraduate student. And all those benefits i have been hearing about them, being able to detect pieces of DNA, even those that exist in very small concentrations with great accuracy, seemed just theoretical.

At some point, when i got interested in DIY biology i started trying to find ways of making such devices. As a result i found a lot more about how they work and how amazing they can be. If you know anything about microfluidic devices though, you already know that trying to make one is nearly impossible without very expensive equipments or wasting a lot of resources (and money) in the process.

Despite that, for large labs whose research depends on those devices the costs end up being reasonable. I would assume that the potential reward for inventing a new functional device is another motivation, since patents for such devices could cost a lot. Many companies use such chips for different uses. In a DIY lab though those devices are not that important since cost is more important than accuracy or uniqueness of the results.

What is a lab on a chip or a microfluidic device?

It is a small platform on which several channels have been drawn. It can have multiple layers and use materials like glass, silicon and copper. Those channels end up forming tubes and with the help of either external or miniaturized pumps, fluid including samples, reagents and buffers can flow through. The size of the channels can sometimes separate specific cells or particles. Sometimes the channels on those devices split the samples equally into multiple chambers, add reagents and the heat them to induce a reaction, thus automatically performing an experiment in a small scale. More complex microfluidic devices work like cassettes, requiring to be inserted into a larger machine. Some other can work passively and perform many tasks at the same time. You just add sample and reagents and watch the fluids flow through hydrophobic and hydrophilic surfaces into the right areas.

A recent study describes a microfluidic device performing an ELISA reaction. It uses a series of chambers to split the samples. This device is based on paper and is using a separator and a platform to separate the reagents and the sample until it’s time for them to interact. The result can be seen through a change in colour.

Another device shown in a recent study involves a series of stacked “platforms”, each performing a different function. This device performs a PCR reaction the size of a very small box fitting in your hands. It has some issues with temperature though. In such a small size it’s hard to have different temperatures within different compartments but they managed to solve this very well. It can perform a full PCR reaction with good results and all their testing seems good. PCR is not that complicated but their design is very interesting because it can mix and deliver the sample into the right chamber at the right time.

Another study even showed a qPCR device although it doesn’t really differ much from the previous device. It mixes, the reagents, heats and cools them, but it uses external equipment for fluorescence detection.

Those devices are really interesting and i thing the best application for them is in a doctors office. Imagine going to your GP and being able to find out which genes or gene variants you have that may be affecting your health or a specific condition you have with minimal costs in a couple of hours. Then the GP would be able to give a better diagnosis and a more appropriate treatment.

You can find out more about such devices by reading my sources linked below or just follow this blog for more science news.

Sources: High-throughput microfluidic single-cell RT-qPCR

Multiplexed and Sensitive DNA Methylation Testing Using Methylation-Sensitive Restriction Enzymes “MSRE-qPCR”

Sliding-strip microfluidic device enables ELISA on paper


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