Early detection is critical to the prevention, treatment, and overall outcome of many catastrophic illnesses, including cancer, heart disease, autoimmune disorders, neurological diseases, and serious infections. The future of microfluidic devices in diagnostics involves growth, innovation, and expansion, in part because they can process very small samples quickly and cost-effectively.
What Is a Microfluidic Diagnostic Device
Microfluidic devices are small chips that may be protected within plastic cartridges. These chips contain tiny channels that behave like capillaries, carrying small amounts of bodily fluids, such as blood or saliva, to meet and interact with diagnostic reagents. These reagents react with the fluid to identify chemical or genetic markers of disease. Microfluidic devices that can sort white blood cells from red and separate cancer cells from the blood are also under development.
Microfluidic devices can also test for drug toxicity on very small fluid samples. This diminishes the need for risky experimentation on human subjects until researchers better understand the effects of the drug in development.
Microfluidic devices are often called “lab on a chip” (LOC) devices because they can perform analyses that previously required full-scale laboratory tests on a chip or credit card-sized device. Unlike full-scale laboratories, microfluidic devices are low cost, portable, and often disposable. They’re also fast and reliable. These tiny devices may have integrated pumps or valves, internal reservoirs to contain fluids for testing, or electronic chips capable of recording and transmitting data.
Many people already use microfluidic devices to monitor their own conditions, from diabetes to kidney disease. Point of care (POC) diagnostic devices that use a simple interaction of fluid with a paper test strip, such as home pregnancy tests, have existed for over-the-counter purchase and home use for decades. However, newer and more sophisticated microfluidic diagnostic devices can produce rapid test results for infectious diseases, from malaria to tuberculosis to HIV. Experts predict the future of microfluidic devices will revolve around advances in diagnosing several more types of diseases.
Microfluidic diagnostic devices can detect genetic markers for certain types of cancer, particularly breast cancer. Researchers at the University of Michigan have developed a device with a labyrinthine structure that can sort blood cells and capture rare cancer stem cells for analysis. Compared to white and red blood cells, these free-roaming cancer cells are exceedingly rare. The new labyrinth-like chip provides a cleaner stream of cancer cells than techniques that used identification of surface proteins. They are also more effective than spiral-shaped chips that used cell size to sort but couldn’t sieve out cancer cells without contamination by many other kinds of cells. The new labyrinth chip speeds analysis because there’s no waiting for cells to bind with other markers or proteins. The blood sample flows quickly through the chip and can be further purified by another trip through a second chip, which adds as little as 5 minutes to the time for sorting.
The future of microfluidic diagnostic devices will probably include chips that can identify autoimmune diseases such as lupus, rheumatoid arthritis, or scleroderma. In a normally functioning immune system, antibodies attack foreign invaders such as bacteria and viruses. With autoimmune disorders, however, these antibodies run amok and attack healthy tissue. These diseases afflict skin, joints, blood vessels, and connective tissue. Researchers are developing microfluidic devices that use a sensitive digital camera to detect specific autoantibodies by the dim light they exude when mixed with a solution containing a photoreactive substance. Though not yet commercially available, this technology holds promise for detecting potentially devastating diseases in future POC devices.
There is nothing like a pandemic to intensify the urgency of diagnosing infectious diseases or detecting the presence of infectious agents or antibodies. Microfluidic diagnostic devices can identify varieties of a flu virus using RNA analysis and chemical reactions. Another technology in development incorporates several different arrays on a chip that may eventually be able to run 128 distinct tests on a finger-prick blood drop. Microfluidics has great potential for use at home to detect infections and some types of cancer. Patients undergoing chemotherapy or in danger of infection can monitor their white blood cell count using such devices. Devices to detect antibodies to sexually transmitted diseases are also in development.
At the University of Illinois at Urbana-Champaign, researchers have developed a rapid test for sepsis, a deadly and fast-moving infection that causes the highest medical costs and the most deaths in hospitals worldwide. The device identifies early signs of immune response by homing in on a surface marker called CD64. This surface maker exists on the types of white blood cells known to surge during the early onset of infection and contribute to inflammation that damages vital organs. The ebb and flow of CD64 correlates with improving or deteriorating vital signs. Researchers are working to add additional markers of inflammation to improve the accuracy of the device in predicting the likelihood of developing sepsis.
Current methods of screening for cardiovascular disease markers are expensive and time-consuming. LOC devices that can detect biomarkers for cardiovascular conditions at the cellular level are less expensive and can provide better chemical adjustments and faster reactions.
The future of microfluidic devices in diagnostics will certainly include partnerships between researchers, manufacturers, and companies that provide product development solutions for life sciences. Teams of biological scientists and engineers in materials, chemical, manufacturing, mechanical, and electrical engineering will continue to work together to discover newer, faster ways to diagnose disease. The processes microfluidic devices can perform will continue to expand, using not only chemical reagents but also electricity microscopic beads to aid in the discovery of disease conditions. Microfluidic devices that can perform genetic analyses to provide predictive information about the risk of hereditary disease will also continue to become more sensitive and sophisticated.
The convenience, reliability, cost-effectiveness, and portability of microfluidic devices bodes well for a future in which the spectrum of point-of-care (POC) diagnostic devices expands. These devices can slash the time required to complete a diagnostic test, in some cases giving nearly immediate results. Some predict that continuing development in diagnostics will also reduce the need for trained technicians to administer and process tests. Others claim that combining LOC and handheld devices that can take your pulse and blood pressure with algorithms deployed on massive health databases will cut the need for doctors substantially.
Microfluidic devices show promise for a future where patients don’t need to wait days for test results, and doctors can provide routine diagnoses remotely based on test results and data these devices provide.