Miniaturization is one of the most important current trends in analytical chemistry because it focuses on the reduction of three critical components: sample preparation, separation, and detection. Methods for miniaturised ion sources based on electron spray ionisation, capillary electrophoresis, solid- and liquid-phase microextraction, and gas chromatography on a chip are a few examples. These technologies are already widely used in commercially available products.
The smallest miniaturisation endpoint, microfluidics, is currently evolving into a powerful technology. Despite the fact that this science has been around for a while, it is only now that its full potential is being realised.
Due to the use of many of the same techniques and materials, microfluidics has been closely linked to developments in the consumer electronics industry as well as in analytical sciences. In fact, the first truly microfluidic device was the inkjet printer. Materials and micro components, on the other hand, are now being used to tailor the technology to specific analytical functions, overcoming portability and cost-efficiency issues and allowing previously impossible experiments.
The ability to precisely control tiny amounts of fluid, on the other hand, has been most frequently used in the medical fields. Thousands of centimeter- and millimeter-scale devices have been created for use in high-value drug production, emulsion generation, cytometry, drug detection, drug dosing, cellular analysis, cancer detection, and a variety of other specialised diagnostic applications.
Microfluidic devices are distinguished by their ability to handle extremely small amounts of fluid, whether as continuous flow in a channel, storage in microwells, or droplets on a chip; typical volumes range from femto- to picolitres (10-15- 10-12 L)! Direct integration of micromachined sensors and actuators is well suited for microfluidic systems because many of their manufacturing processes were originally developed for the semiconductor industry: Labs-on-a-Chip!
An entire lab-on-a-chip
The desire to create lab-on-a-chip (LOC) devices has been one of the driving forces behind the development of microfluidics. These microfluidic tools can perform one or more laboratory tasks on a single chip. DNA microarrays, flow cytometers, biosensors, and electrophoresis are some examples. These tools are extremely useful in molecular biology, diagnostics, and drug development because of their exceptional automation capabilities.
Organs on a chip (OOC) technology is another angle on this field of study. In comparison to current methods of cell culture and animal testing, these aim to recapitulate the behaviour of cells, organs, and entire organ systems. They might also support a move away from animal testing that is motivated by ethical and practical considerations. Microfluidics is perfectly suited to accomplish this goal due to its small scale and ease of manipulation. In an OOC device, cells can be cultured while having every aspect of their environment, including their exposure to microbes, mechanics, and nutrients, carefully controlled. Such technology could eventually pave the way for basic human biology discoveries as well as personalised medicine, which involves using a person’s own cells to create a model organ.
Microfluidic Systems are Dependable as well as Efficient
Microfluidic devices, which are palm-sized chips with complex microscale circuits and channels linked by tiny tubings, circulate fluid samples. While sampling minute amounts of fluids and reagents, the systems frequently integrate with other detection technologies to produce prompt analyses and successful results, and channel geometries and designs are customised depending on the device’s purpose and application.
- the ease of customization and production,
- the ease of customization and production,
- the manufacturing materials,
- the ability to manipulate (bio)particles flowing in introduced fluid samples precisely and accurately,
- Microfluidic technology is exceptional in terms of efficiency and quality, as it can produce consistent, successful results with a very low percentage of error.
Furthermore, when compared to traditional diagnostic methods, the process takes minutes rather than hours or days.
Microfluidics are Practical & Portable
Microfluidic devices are compact and small in size because they combine multiple laboratory procedures on a single chip. It has a substantial advantage in terms of portability, accessibility, and usability.
Patients can use LOCs at home for health assessment and monitoring in addition to checking their electrolytes while taking a diuretic and their blood urea nitrogen and serum creatinine levels if they have chronic kidney disease.
LOCs have also been used to make rapid diagnoses of infectious diseases such as HIV, tuberculosis, hepatitis, and malaria. Patients in developing countries and areas with limited resources may benefit the most from this.
Microfluidics is economical.
In addition to its high efficiency and convenience, microfluidics has the critical advantage of having a low production cost per device when compared to other technologies. This allows for increased production efficiency as well as disposal.
Scientists believe that a microfluidic device capable of producing quantitative results in under one minute while requiring as little as one microliter of sample volume and costing less than one dollar to mass produce will become a reality in the not-too-distant future.
The two main aspects of this cost-effectiveness are the materials used to make microfluidic devices and the manufacturing procedures.
- Silicon is a critical component in microfluidics. It is a unique material due to its surface stability, solvent compatibility, and thermal conductivity. Nonetheless, optical detection is difficult due to its opacity.
- In addition to transparency, high-pressure resistance, biocompatibility, and hydrophilicity, glass is an effective material with properties that outperform those of silicon. Its main disadvantage is that it is more expensive than the average.
- The most frequently used polymer for fabrication is polydimethylsiloxane (PDMS). PDMS is advantageous for cell cultures and processing because it is affordable, transparent, elastic, and gas permeable. PDMS is still widely used in microfluidics despite its shortcomings, such as deterioration and poor chemical compatibility with some organic solvents.
Another material with great potential for use in the fabrication of microfluidic chips is paper. This option stands out due to its low price, thinness, light weight, biocompatibility, disposability, ease of manipulation, and storage. It still demonstrates the difficulty of patterning chip channels.
Hydrogels are also potential candidates for microfluidic equipment due to their malleability, biocompatibility, commercial availability, non-toxicity, and low cost.
Despite the fact that microfluidic platforms have several advantages in terms of safety, cost, and process control, there remain challenges that necessitate additional engineering and research.
Examining manufacturing tolerance results is one of these areas. Since the channels are so narrow, deviations from the intended cross-section profile can have a significant impact on elements like pressure drop or mixing behaviour. Another topic that frequently causes issues is multiphase flows. When two immiscible fluids combine at a junction, microdroplet generators produce highly repeatable droplet size distributions; these are frequently used in emulsions for drug dosing and encapsulation. Microbubbles could also be useful in gas-liquid reactions that require extremely rapid mixing. Similar to surface-bound catalyst particles in manufacturing or single-cell sorting in diagnostics, solids entrained in a flow enable better process control.
These multiphase microfluidic processes can have extremely difficult physics. Many adjustments must be made to the channel sizes, shapes, pressures, and flow rates in order to produce the desired droplet or bubble size.
Understanding the properties of the channel and particle surfaces, as well as determining whether specific flow patterns will reduce the likelihood of biological cells or catalyst particles adhering and blocking, is critical. These granules can clump together or adhere to walls, creating a hazard.
When Body & Microfluidics Interacts
Microfluidic devices’ future applications are likely to include direct integration with the human body, in addition to laboratory-based research. The fundamental incompatibility between the elastic, dynamic nature of tissue and rigid electrical components presents a number of challenges, not the least of which is the current situation.
Scientists have recently developed and worn on the skin microfluidic devices that resemble transfer tattoos. John Rogers’ lab at Northwestern University developed one such device, a battery-free continuous monitor that removes sweat from the skin and provides real-time information on electrolyte concentrations and perspiration rate. Although the team has already identified professional athletes and stroke patients as potential beneficiaries, there are likely to be many more applications.
Furthermore, technology will most likely make it easier to measure the numerous externally derived medical observations, such as heart rate, blood pressure, skin temperature, and respiration rate. It may be especially important in this case to eliminate the numerous sensors and wires currently required for continuous monitoring of premature newborns in neonatal care settings.
Microfluidics has a lot to offer in terms of science and technology. As a result, future capabilities will be fantastic, if not revolutionary. Furthermore, it is still in its infancy and requires significant development before it can be considered more than a current field of academic study. The foundations of the field, on the other hand, are extremely strong.
Much of the world’s technology is based on the ability to manipulate fluids and extend those manipulations to small volumes with precise dynamics. The ultimate goal is to achieve concentration control while understanding and utilising novel microscale fluid phenomena, which is critical.