What is Microfluidics?

author:

Heeho Ryu

Posted On:

2024-05-12

Category:

Microfluidics 101

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Introduction

Microfluidics is a fascinating and rapidly evolving field of science and technology, sitting at the intersection of physics, chemistry, biology, material science, microelectronics, and nanotechnology. Taking advantage of the unique properties of fluids at the nanoscale* such as laminar flow, effective heat transfer, and higher surface-to-volume ratio, microfluidics enables the development of low-volume fluid processing systems that are extremely fast, efficient, and precise. Traditional laboratory operations such as mixing, separation, particle isolation, and compound detection can be miniaturized and automated onto simple, portable, and cost-effective microfluidic devices. This not only reduces sample and reagent use and waste, but also increases the speed, resolution, and controllability of reactions.

Microfluidics has been applied to a diverse range of fields from diagnostics, drug discovery, biological research, materials discovery, and environmental monitoring to much more. New and exciting possibilities in scientific research and technology development have been made possible thanks to microfluidics. In essence, microfluidics is a tiny technology making huge splashes across the world.

*From 10–9 to 10–18 liters, that’s smaller than a single droplet!

How does microfluidics work?

At its core, microfluidics involves the movement and manipulation of various fluids through microchannels and chambers that range in size from submicrons to a few millimeters. They can be molded, machined, or engraved into custom cartridges* made out of glass, silicon, polymers, and even paper. Fluid dynamics and behaviour at such scale are quite different from those we experience in everyday life, and scientists and engineers take advantage of these unique properties to achieve precise control over the fluids.

Microelectronic and mechanical components such as valves and pumps are used to create pressure-driven flow in the cartridge, mixing, separating, and directing the fluids by pushing them forward or pulling backward. Different types of sensors are capable of monitoring conditions like flowrate and temperature, and detecting the presence of particulates and microorganisms. Application of the latest machine learning techniques and artificial intelligence have enabled real-time reconstruction of microscopic images and faster, more accurate identification of sample anomalies.

*Also referred to as chips or cards.

What’s so great about microfluidics?

With roots in microelectronics, biodefense, and molecular biology, microfluidics arose from the need to conduct precise, sensitive, compact, and versatile chemical and biological analyses across a diverse array of fields and industries. Some of the key innovations and advantages that microfluidics offer include:

  • Precision & Control: Microfluidics empower researchers to have greater control of experimental parameters, material usage, and operational processes at the nanoscale. Precise dosage and manipulation of samples and reagents have enabled high-throughput, multiplexed assays with increased resolutions and sensitivity.
  • Speed & Cost-Efficiency: Microfluidic, as per its name, requires the smallest amounts of reagents and samples for rapid sample processing and high quality analyses. Faster heating, cooling, and mixing translates to less time spent on preparing samples and running experiments. It also means lower resource consumption, making any type of experiment more economical and environmentally friendly compared to existing laboratory processes.
  • Customizability: Microfluidic cartridges and devices are highly customizable, and can be tailored to meet the specific needs of each user, project, and application. The cartridges and devices can be fabricated using a range of the latest materials that are best suited in terms of cost, biocompatibility, and ease of manufacturing.
  • Portability & Ease-of-Use: Microfluidic devices are compact, portable, and easy to use, leading to innovations in a diverse array of fields from health and medicine to international development and environmental conservation. Microfluidics has revolutionized point-of-care testing with diagnostic tools that can identify infections within minutes; low-cost and low-maintenance environmental monitoring devices provide efficient tools for assessing the quality of water, air, and soil. These devices can be used in remote and resource-limited settings, significantly enhancing global health outcomes where traditional laboratory infrastructure may not be available.
What are some examples of microfluidics in action?

Microfluidics is a versatile technology with an endless list of possible applications. From healthcare, medicine, biochemical research, food safety, and resource management to chemical production, microfluidics is revolutionizing several industries through its speed, precision, and cost efficiencies. Here is a list of some of the most notable applications of microfluidics:

  1. Lab-on-a-chip (LoC):
    Complex laboratory procedures and biochemical processes can be miniaturized and automated onto tiny cartridges called lab-on-a-chip (LoC), increasing the speed, control, and accuracy of the procedures while reducing waste and costs. For instance, LoC polymerase chain reaction (PCR) devices automate the process of preparing PCR reactions, which minimizes the risk of contamination and human error that often lead to false results. In genomics research, LoC devices can conduct high-speed thermal cycles required for DNA and RNA amplification, enabling rapid genetic sequencing and detection that reduces analysis time by 10 to100 times compared to the traditional approach.
  2. Point-of-Care (PoC) Diagnostics:
    Microfluidic diagnostic devices can analyze tiny samples of blood, urine, saliva, sweat, and tears to provide rapid but accurate diagnosis of various disease and conditions on site. PoC devices are cost-effective, easy to administer, and minimally invasive, allowing diagnostics to be conducted in clinics, emergency rooms, patient’s bedside, homes, and even remote or resource-limited settings where timely diagnostics and treatment are vital, but very small volumes of patient samples may be available. They have been used to detect glucose levels, hormones, cancers, heart attacks, and viruses (i.e. COVID-19, HIV), leading to early diagnoses and reduced hospital visits.
  3. Organ-on-a-Chip (OoC):
    OoC refers to 3D microfluidic cartridges that grow living cells and accurately model the structure and function of human organs, including the heart, brain, kidneys, liver, and lungs. OoCs play a significant role in drug discovery, disease modelling, and drug delivery as it can mimic bodily processes like breathing, infections, and muscle movements. OoCs expedite drug discovery and development by allowing researchers to quickly and effectively predict drug safety, saving costs and reducing our reliance on human and animal testing. Personalized ‘patient-on-a-chip’ can be made using patient-derived tissue samples, accelerating the process of researching and developing new treatments for various cancers and rare diseases. Novel drug delivery systems using microfluidics enable targeted delivery, precise dosage, and highly controlled drug release, minimizing the side effects of pharmaceutical treatments.
  4. Environmental Monitoring:
    Traditional environmental monitoring systems (EMS) require large and expensive equipment, highly trained operators, and samples to be sent to centralized labs. This translates to longer processing times for analyses, making them impractical in many settings, especially those that are remote or resource-limited. Microfluidic devices on the other hand, are cost-effective, portable, user-friendly, and time saving while also being highly sensitive, selective, and reliable, even with the lowest concentrations of analytes. Microfluidic EMS devices require minimal samples, enable rapid analysis and real-time assessment, and automate multiple chemical processes, making them ideal for diverse field-settings. They have been used to detect and monitor contaminants in water, air, and soil including heavy metals, pesticides, bacteria and viruses, and polyfluoroalkyl substances (PFAS).
Future of Microfluidics

Microfluidics might sound like science fiction, but it’s very much a part of our present reality. Have you ever used a rapid COVID antigen test? If you have, you have seen first-hand how microfluidics can be applied in the real-world and impact our everyday life. By understanding and manipulating fluids on a microscopic scale, researchers and engineers are creating powerful tools that are making our world healthier, cleaner, and more efficient. Whether it’s diagnosing diseases faster, developing new drugs, or keeping the environment clean, microfluidics is a tiny technology with huge impacts.

References and Further Reading
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  • Battat S, Weitz DA, Whitesides GM. An outlook on microfluidics: the promise and the challenge.
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  • Dittrich PS, Manz A. Lab-on-a-chip: microfluidics in drug discovery. Nat Rev Drug Discov. 2006;5(3):210-218.
  • Esch 2015. Organs-on-chips at the frontiers of drug discovery
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  • Gharib G, Bütün İ, Muganlı Z, Kozalak G, Namlı İ, Sarraf SS, et al. Biomedical Applications of Microfluidic Devices: A Review. Biosensors. 2022 Nov 16;12(11):1023.
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  • Leung 2022. A guide to the organ-on-a-chip
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