Microfluidic device could save lives by speeding up the diagnosis of sepsis

Researchers at the Michigan Institute of Technology have come up with a new sensor that could dramatically speed up the diagnosis of sepsis and save lives by identifying the disease before it's too late.

Credit: Felice Frankel

The small microfluidic sensor can detect a biomarker of sepsis called interleukin-6 (IL-6) in tiny volumes of blood in about 25 minutes. The device could offer an inexpensive and more sensitive alternative to current point-of-care systems for detecting sepsis, which kills nearly 250,000 patients each year in the United States.

Sepsis requires rapid diagnosis for effective management

Sepsis occurs when the immune system triggers a chain of inflammatory reactions throughout the body in response to an infection. The potentially fatal response causes high heart rate, severe fever, shortness of breath and can cause septic shock, a drop in blood pressure and arrest or failure of organs.

To diagnose sepsis, doctors traditionally rely on vital signs, blood tests, and other imaging and laboratory tests, but diagnosis of sepsis in time for effective care to be provided remains a problem. challenge.

Traditional tests for the detection of sepsis biomarkers also often require expensive and bulky devices requiring one milliliter of blood and making detection impossible outside the hospital setting.

In recent years, various on-site treatment devices have been developed capable of generating microliter results in approximately 30 minutes, but are generally expensive because they primarily use expensive optical components to detect biomarkers.

In addition, they only catch a tiny amount of protein, many of which circulate among the most abundant blood proteins.

In addition, any attempt to reduce the cost of these devices, the size of their components or to increase the range of detectable proteins reduces their sensitivity.

Interleukin-6 as a biomarker of sepsis

In recent years, researchers have identified biomarkers of blood proteins that are early indicators of sepsis. The blood level of one of these biomarkers – IL-6 – begins to increase several hours before the onset of other symptoms of sepsis, making it a promising candidate for early detection. However, even at these increased levels, the concentration of IL-6 in the blood is too low to be quickly detected by traditional test devices.

A research article to be presented at the "Engineering in Medicine and Biology" conference in Berlin describes a microfluidics-based system that can detect clinically significant levels of IL-6 in about 25 minutes, using less than one sting of blood. .

"For an acute disease, such as sepsis, which is changing very rapidly and can be life-threatening, it is useful to have a system that quickly measures these scarce biomarkers," says lead author Dan Wu. . "You can also frequently monitor the course of the disease."

Miniaturization of an baday based on magnetic beads on a microfluidic device

In an effort to design a more affordable alternative to current treatment systems at the point of care, MIT researchers undertook to miniaturize a test based on magnetic beads on an automated microfluidic device measuring approximately several square centimeters.

In one of the microfluidic channels of the device, antibody-containing microbeads mix with blood to capture IL-6 and in another channel the beads containing the biomarker bind to an electrode. When the voltage is traveled by the electrode, it generates an electrical signal for each bead containing a biomarker and the generated signals are then translated into a concentration level for the biomarker.

Benefits of the new platform compared to current systems

Even slight increases in the IL-6 can be detected during a test and, if samples need to be processed in parallel, more channels can simply be added to the device. Currently, the design includes eight microfluidic channels that can simultaneously measure as many different biomarkers or blood samples.

"This is a very general platform. If you want to increase the physical footprint of the device, you can increase the size and design more channels to detect as many biomarkers as you want, "says Wu.

The compact device is inexpensive compared to existing portable systems, easy to use and only requires 5 microliters of blood to test IL-6 levels.

"For their part, doctors are just loading a blood sample with the help of a pipette. Then, they press a button and 25 minutes later, they know the concentration of IL-6, "adds Wu.

Will we see this technology in the clinic soon?

The technology is not yet ready for clinical use in hospitals, but improvements are being improved. An example includes the ability to detect other biomarkers of sepsis, among which more than 200 examples have been approved by the FDA.

If the device is finalized, clinicians may be able to detect sepsis before it's too late and save lives, even in health facilities where the use of current platforms would not be convenient.