Microfluidics

The miniature wonderland for researchers

 

 

As we learn more about the living systems around us, research becomes more and more specific – from understanding an animal by looking at its cells, to understanding each chemical reaction that happens inside its body. Focus keeps getting narrower and with it, the scientific techniques get smaller too!

Microfluidics is a key technique allowing scientists to focus on their study scope while maintaining high accuracy. The basic scaffold of a microfluidic system is a chip with channels thinner than a human hair through which liquid samples travel along a circuit with valves. These channels can be made from glass, polymers, or even paper. And the fluid can be propelled using a pump or through natural properties like capillarity or movements due to surface charges.

This kind of system can be found in many objects of our everyday life, for example, the flow of ink in pens, paper strips from pregnancy tests or inkjet technology in printers. Lately, scientists are optimising its experimental capabilities for research and engineering uses.  Microfluidic systems can miniaturize the work of a whole lab onto a chip less than a few centimetres long, providing technical (and economical!) advantages that are hard to overcome by conventional techniques. That’s why they are becoming quite a trend in labs worldwide: a quick search in PubMed of the term “microfluidics” gives more than 40,000 results! What are the advantages of microfluidics and how is it changing the way we do research?

Small, but tough

Size does matter, and the small shape of microfluidic chips is a key aspect of their perks. First off, they are easily portable, facilitating their transportation and storage. It also means these systems can work with really small samples and reagents. From microliters to femtoliters, microfluidic uses liquid samples that are 9 times smaller than a drop, which is only 50 microliters. Therefore, they reduce the volume of the source product that needs to be analysed, thereby providing significant cost savings.

The core of their functionality is also linked to their size. After the liquid is propelled onto the chip’s channels, it has very little liberty to move. Thanks to this size restriction, flow through the channels is mathematically predictable, called laminar flow. Knowing how the samples are going to behave beforehand allows a lot of precision for scientists and boosts reproducibility.

Organizing the channels and valves of the microfluidic systems, scientists can recreate biological scenarios quite efficiently and test their hypotheses. The pattern of channels can be modified and functionalized for specific applications such as detecting changes in concentration, pH and temperature, among others and thereby, increasing the number of applications for microfluidics technology.

Another advantage related to the small size of microfluidic circuits is the restricted space available for the samples inside the chip. Everything happens at a tiny scale, and this allows molecules to interact faster, thus reducing reaction times. This small size also increases sensitivity because the dimensions of the whole measuring system are greatly reduced.

Apart from their size-based perks, microfluidic chips also have the fundamental advantage of being independent of electronic components. Microfluidic devices can be paper based, among other materials, reducing their price and even better, reducing the amount of electronic waste to the environment!

All of these characteristics have allowed microfluidic devices to be used in many different applications in just a micro-scale.

An asset not only for scientists

The advantages of microfluidics don’t just stay on paper. Let’s take a look at some of the applications of this technology, which aims to solve great problems in science.

First of all, thanks to the compact shape of microfluidic systems, they are a perfect fit for NASA space missions, where sample size and transportation are major concerns. Using this technology, scientists from NASA developed a Mars Organic Analyzer, which is an instrument used as an amino acid biomarker to detect the fundamental elements that constitute life as we know it, on Mars.

Microfluidics systems have also been used in the field of life sciences. One of the best examples is their use for live imaging of the nematode C. elegans. This organism has a simple nervous system and is transparent, which allows scientists to study its cell development and changes. However, scientists needed to immobilize the worm to take high resolution images. Conventional methods used drugs or even glue… which could be irreversible and hurt the animal. Luckily, microfluidics systems have been designed to reversibly trap these worms and manipulate them within the platform.

Also in this same field, microfluidic systems have been used for cell analysis because of their sensitivity and small size, comparable to that of a single cell. These systems have been used as cellular biosensors to understand the physiological responses of a cell to different environments, like pH changes or toxins. Moreover, they can be used to study single molecules, like enzymes, which is what we are doing in RadicalZ.  Microfluidics chips allow us to identify the best enzyme for a desired job and isolate it from its sources.

Taking advantage of their portability, microfluidic systems can also be useful in medical practices, like the development of point-of-care devices. These devices allow medical analysis to be performed in the proximity of the patient. In fact, we already use some of them in our daily lives: glucose biosensors, screening of drug abuse and pregnancy testing.

Microfluidics is taking the lead in the field of biomedical research and engineering, and it seems to have come to stay. No wonder it has become quite the trend in labs worldwide, thanks to its unique chemical and physical features. Now, we can only ask, what will be the next step in this microfluidics revolution?