Microfluidics is the general term for the manipulation of nanoliter volumes of fluids through micro-channels. The field has led to the development of microfluidic devices or chips which are commonly used for high-throughput screening in the biosciences.
Microfluidic devices can integrate sample preparation and detection on microassays, scaling down different laboratory functions onto one chip. Microfluidics is being applied to both the formation of nanoparticles and utilizing them for applications such as the detection of cancer and the diagnosis of infectious diseases.
Advantages of Applying Microfluidics to Life Science Nanotechnology
Nanotechnology has vast potential for use in the life sciences but particularly in the detection and treatment of diseases. For practical applications, any methodologies developed require the consistent production of nanoparticles in high quantities as well as techniques for rapid screening.
Microfluidics are enabling solutions to these problems and therefore bringing the technology a step closer to frequent clinical applications. Organic molecules can assemble into nanoparticles when a change of solvent quality occurs, usually by mixing the solvent with an antisolvent.
Microfluidic devices have been developed that form organic nanoparticles via rapid mixing without the need for an external means of force. Inorganic nanoparticles, such as gold, can also be formed in bulk through this technology as metal solutes agglomerate into clusters.
Microfluidics allow for the synthesis of nanoparticles with different size, shape and surface structures. This is particularly important for the formation of nanoparticle libraries as utilized in gene therapy. Before treatment through gene therapy can commence, the correct formulation of nucleic acids for a specific target site must be inferred.
Microfluidic devices can synthesize libraries of polymeric and lipid nanoparticles which enclose DNA. The libraries can then be screened to provide the correct formulation needed for the gene therapy.
Microfluidic Devices and Nanotechnology for Cancer Detection
An important part of cancer detection is the quantification of biomarkers, which are measurable indicators of the disease. Microvesicles are one such biomarker, being small portions of plasma membrane shed by circulating tumor cells.
As the parent cells are not abundant in the blood stream, the detection of microvesicles is an important indicator of cancer. A nano-filter was developed that can isolate microvesicles of less than 200 nanometers through the use of ultrasound standing waves on a microfluidic device.
Acoustic forces isolate microvesicles based on their size due to the differential forces that occur at various particle sizes. This method may be used as a preparatory tool before microvesicle analysis for cancer detection. Further integration of quantification components in the future may allow for portable lab-on-a-chip analysis that can be performed on a small volume of blood in any location.
Microfluidic Devices and Nanotechnology for Infectious Disease Detection
The combination of nanotechnology on microfluidic devices has enhanced testing for infectious diseases such as malaria, tuberculosis and the HIV virus. Improved testing technology is particularly necessary in poorer regions that are disproportionately affected by these diseases.
It is important that diagnosis methods in these areas are low-cost, simple to use and have the same sensitivity as equivalent laboratory-based tests. Microfluidic devices and nanotechnology have the advantage of requiring a smaller sample size to produce testing results with increased sensitivity.
This is allowing for the increasing utilization of point-of-care testing, where a diagnosis is produced at the same time and place as patient care.
An example of this technology has been applied to form a nanoparticle-based tuberculosis diagnosis strategy. A gold nanoparticle probe assay was produced for the detection of the bacterium Mycobacterium tuberculosis.
The probe is formed by attaching gold nanoparticles to short strands of DNA that are complimentary to target portions of Mycobacterium tuberculosis, if contained in the sample.
The gold nanoparticle provides an optical method of detecting the binding of complimentary DNA to the bacterial DNA as a visible color change. This is because gold nanoparticles produce a color change phenomenon when concentrated. A portable version of the gold nanoparticle probe assay has been fabricated to increase its suitability for fieldwork.
Shelley Farrar Stoakes, MSc, BSc
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- Lee, K. et al. 2015. Acoustic Purification of Extracellular Microvesicles, American Chemical Society Nano, 24, pp. 2321-2327. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4373978/
- Damhorst, G. et al. 2015. Microfluidics and Nanotechnology for Detection of Global Infectious Diseases, Proceeding of the IEEE, 103, pp. 150-160. http://ieeexplore.ieee.org/document/7067024/
- Wang, S. et al. 2013. Point-of-Care assays for Tuberculosis: Role of Nanotechnology/Microfluidics, Biotechnology Advances, 31, pp. 438-449. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3602163/