Stanford innovation promises real-time continuous blood monitoring
Continuous monitoring of changes in patients' blood would be a profoundly transformative advance for doctors and a team of Stanford bioengineers has brought us one step closer to that reality. New research in the journal Nature Biomedical Engineering describes a novel device with the potential to detect real-time changes in blood levels of any molecule or protein a doctor would need to monitor.
“A blood test is great, but it can’t tell you, for example, whether insulin or glucose levels are increasing or decreasing in a patient,” says Tom Soh, one of the engineers working on the new research. “Knowing the direction of change is important.”
One of the more common technologies used to detect specific molecules in a blood sample is an Enzyme-linked Immunosorbent Assay, or ELISA, which can detect almost any kind of antibody, hormone or protein.
The innovative new system has been dubbed by the researchers Real-time ELISA (RT-ELISA). The landmark system is an impressive evolution of ELISA technology, turning a one-off test into a device that continuously feeds intravenous drops of a patient’s blood into what is essentially a tiny lab-on-a-chip.
The prototype RT-ELISA device is made up of three modules. The first module (seen in the bottom part of the picture above) mixes a blood sample with antibodies designed to react with whatever molecule is being targeted.
The top part of the device is split into two modules, one designed to move out excess blood cells while another collects fluorescent antibodies into a detection window. A high-speed camera monitoring the detection window then tracks how brightly the sample glows, giving clinicians the ability to watch levels of a targeted protein or hormone change in real-time.
The RT-ELISA prototype was tested on diabetic rats and shown to effectively detect real-time changes to glucose and insulin levels in the animals' circulating blood. However, Soh suggests this system could be used for much more than just monitoring blood glucose changes.
“Don’t think of this as just an insulin sensor,” he adds. “Think of this as a way of doing ELISA in a completely new and different way.”
One potential use for the system is preventing sepsis, a condition where the body’s immune system overreacts to an infection and produces a heightened volume of inflammatory molecules called cytokines. A common cause of death from COVID-19 is thought to be due to these “cytokine storms.”
The RT-ELISA prototype is currently being adapted to detect IL-6, a cytokine known to be a marker of sepsis severity. It currently takes up to three days to get IL-6 blood test results back from a laboratory. Soh points out how transformative it would be for intensive care physicians to have access to IL-6 blood fluctuations in real time.
“In sepsis, time is key – every hour that goes by, your probability of dying increases by eight percent,” says Soh. “Patients don’t have three days for a single test. That could have life-saving implications.”
This preliminary study is very much a proof-of-concept showing how this kind of continuous real-time blood monitoring could be done. Plenty more work is necessary before this technology is refined and reaches clinical use but the researchers are confident it can be readily modified for human use.
The new study was published in the journal Nature Biomedical Engineering.
Source: Stanford News