Microfluidics is a field of research that develops fluid-processing technology at the microscale. Like a circuit board for liquids, microfluidics work with tiny devices (or chips) patterned with small channels and ducts through which liquids move. In such compact and constricted conditions, liquid displays unique behaviors that, when manipulated, can provide fast results at high throughput.
What Is Microfluidics?
Microfluidics refers to the study of liquids moving through channels in micro-sized devices, as well as the practical application of such systems.
Household items, like an inkjet printer and at-home pregnancy tests, employ microfluidic technology; however, the most common microfluidic application is in medicine.
With microfluidics, “a workflow that would require the floorspace of an entire lab can be implemented in a single instrument,” Tobias Wheeler, a senior director of microfluidics engineering at gene-sequencing biotech company 10x Genomics, told Built In.
A variety of diagnostic test kits — from detecting toxins such as Covid-19, diabetes or simply running a blood panel — use microfluidics for rapid, on-site point of care. It’s also used in more advanced procedures, like DNA sequencing and genomic single-cell analysis. Microfluidics can also be seen in the public health sector: identifying contaminants in a drinking source, tracking biothreats in national defense and monitoring the quality of perishables in the food and beverage industry.
With a wide variety of applications, it’s a tiny technology making an outsized impact.
What Is Microfluidics?
Microfluidics is an emerging technology that uses micro-sized devices with channels and tunnels through which small amounts of liquid flow.
“On a microscale, the physics of fluids can be non-intuitive,” Manasi Raje, a chemical engineer that develops synthetic DNA-based products at Twist Bioscience, told Built In. What results are highly predictable, orderly fluids that flow in parallel streams. This phenomenon, known as a laminar flow, is what makes the precision work of microfluidics possible.
By shrinking the study of liquid flow states, microfluidics has given way to an ocean of multidisciplinary scientific discovery. It’s created precise, automated processes that deliver high-yield results in real time. These systems are typically inexpensive to manufacture, and capture large scale studies with minimal sample volume while preserving precious fluids (like human blood) and limiting exposure to hazardous actors (like antibodies and radiopharmaceuticals).
“Microfluidic technologies simply provide ways to build cheaper, more efficient analytical systems and perform high-throughput tests with minimal use of [resources],” Atul Dhall, microfluidics and biomaterials researcher, told Built In. “They have potential impacts across all industries where fluid dynamics are important.”
Microfluidics and Lab-On-a-Chip
The holy grail of microfluidics is something called a lab-on-a-chip. As the name suggests, the idea behind a lab-on-a-chip is to “integrate all the important aspects of a biological experiment within a single platform,” Dhall said.
Currently, researchers are competing to develop a variety of “on-a-chip” biomimetic systems. These polymer-silicone credit cards contain living human stem cells that replicate human physiology in both structure and function. Kidneys, livers, lungs and hearts have already been successfully transferred to organ-on-a-chip devices in a lab setting while tumor-on-a-chip platforms diligently monitor cancer progression and test the effectiveness of certain therapies. During his postdoctoral research at the University of Pennsylvania, Dhall developed a dental implant-on-a-chip designed to combat oral infections.
The purpose of this technology is to provide personalized treatments, more accurate models for drug development and disease modeling as well as reduce animal testing.
How Does Microfluidics Work?
A microfluidic system — which may be fabricated from plastic, glass, gel or even paper — is engraved with a pattern of narrow microchannels and reservoirs. Then, fluids are loaded into their respective inlets and driven through the microchannels using a variation of methods. Some devices are built with pumps and valves to create a pressure-driven flow; others leverage surface tension forces to pull the solution through its channels. Circular designs may simply lean into centrifugal force to establish a flow, while others mobilize liquid by charging particles within the solution or a chip’s infrastructure with electricity.
These interactions will result in one of three outcomes, according to Wheeler. When combined, the substances may cause a chemical reaction, create a product (such as a water-in-oil-type emulsion or an integrated, functional structure made out of microparticles) or a separation (in biomedicine, this may be removing cancer cells from a blood sample).
Applications of Microfluidics
Microfluidics power many point-of-care tests used to detect important biomarkers. From a small sample of spit or blood, these rapid, on-site analyses can indicate whether a patient has acquired an infectious disease, such as Covid-19, or read a diabetic patient’s glucose levels. It’s also used in blood chemistry panels, which provide a general status update on organ function and help find abnormalities.
When researchers break up a biopsy sample into individual cells, then place these cells all throughout a microfluidic chip, they’re able to launch a battery of tests in one go that help inform a treatment plan. Mimicking in vivo conditions, these labs-on-a-chip enable researchers to see how a cell type interacts with certain drugs and the efficacy of that drug before it’s even prescribed to the patient.
Cell Culture and Tissue Engineering
Microfluidics is also used to simulate an in vitro environment for applications that use live tissue. This approach aids in lab-grown tissue development, building artificial structures that both resemble and perfuse like their natural counterparts. One notable, up-and-coming innovation delivers physiological replicas of human organs on a USB-stick-sized chip. These organ-on-a-chip devices simulate the behavior of an entire human organ. They serve as cross sections of the human body lined with living cells, and may provide a more accurate model for drug development, disease modeling and personalized medicine than conventional methods. So far, engineers at the Wyss Institute have captured the microarchitecture and function of human lung, intestine, kidney, skin, bone marrow and blood-brain barriers in their lab.
DNA sequencing looks at the order in which the four building blocks — adenine, cytosine, guanine and thymine – make up an individual molecule. The more we know about our genes, mutations and genetic variations, the better we can understand how we inherit diseases or evolve. At Wheeler’s company, 10x Genomics, microfluidics is used to pair individual cells with tiny DNA-barcoded “gel beads” for single cell sequencing. During this process, thousands of tiny droplets are generated from a specific sample, which allows for a more in-depth analysis of gene expression profiles that enable researchers to explore biological processes and systems on a cell-by-cell basis.
Microfluidics is used to help downsize and automate the gene-editing workflow. Its miniature, droplet-based mechanisms deliver gene-editing materials directly to a cell, where it can insert, replace or delete parts of a DNA sequence with precision and accuracy. Ideally, this practice would be used to correct known mutations that cause cancers and disease.
Water Quality Analysis
Traditional, labor-intensive methods of water quality analysis — such as collecting samples from different locations, delivering them to a lab, then running them through tests — pale in comparison to microfluidic alternatives that can deliver on-site results in real time. A range of tools, from electrode systems to paper test strips, can be used to detect and quantify pollutants and contaminants in a water source.
Air Quality Analysis
Microfluidic devices can be used to detect particulate matter in the air as well as gaseous pollutants, like a carbon monoxide detector. Some models may even be equipped to monitor the presence of airborne pathogens or allergens by capturing floating microorganisms, such as bacteria or mold spores, then reporting its air-quality findings via a readout.
Given its molecular-level sorting capabilities, microfluidics may be a viable filtering method to combing out microplastics from the ecosystem. A 2023 study published in the journal Biosensors outlines several proven methods of using microfluidics as a separation tool, ranging from acoustic forces activated by piezoelectric actuators to electrical and mass-based approaches.
Frequently Asked Questions
What are microfluidics used for?
Microfluidic systems are used for DNA analysis, drug discovery, cell culture engineering and environmental monitoring, among other applications.
What is meant by lab-on-a-chip?
In microfluidics, lab-on-a-chip refers to a single device that integrates all the important aspects of a laboratory.