Chip Device Quickly Detects Sepsis in Blood

Lab-on-a-chip device testing for sepsis (Janet Sinn-Hanlon, University of Illinois – Urbana)

3 July 2017. An engineering team designed a lab-on-a-chip device that in tests with hospital patients shows it can find signs of sepsis in a drop of blood in about 30 minutes. Researchers from University of Illinois in Urbana describe the device and their findings in today’s issue of the journal Nature Communications.

The team from the lab of biomedical engineering professor Rashid Bashir, with colleagues from Carle Foundation Hospital, also in Urbana, are seeking faster and more reliable methods for detecting early signs of sepsis, a life-threatening infection often contracted in hospitals. The disease results from an immune-system reaction to chemicals released by the body to fight infection, including infections from medical equipment such as catheters.

These inflammatory immune responses can occur anywhere in the body and generate a series of further reactions, including blood clots and leaking blood vessels, causing organ damage and failure. If sepsis develops into septic shock, blood pressure drops sharply, often causing death. Centers for Disease Control and Prevention reported in 2011 that the number of people in U.S. hospitals with sepsis rose from 621,000 in 2000 to more than 1.1 million in 2008, with death resulting in 28 to 50 percent of cases.

Sepsis, however, is difficult to diagnose, since the early symptoms can be attributed to any number of causes. And since sepsis develops quickly, there’s a need to quickly determine if a patient is suffering from the condition. Rashid’s lab studies lab-on-a-chip devices that can be used at the point-of-care for disease diagnostics, rather than sending out patients specimen samples for analysis. The device developed in this study measures leukocytes and neutrophils, white blood cells in the immune system highly correlated with sepsis reactions, particularly cells expressing a protein known as CD64, an indicator of sepsis.

The chip needs only 10 microliters of whole blood, barely a drop, for its analysis, directly from the patient. The sample flows through fine channels in the chip, with electrical signals sent through the blood. The device measures the extent of impedance in the signal as blood cells pass by, which enables attached instruments to keep count of cells with characteristic impedance patterns for leukocytes and neutrophils expressing CD64 proteins.

The Illinois researchers tested the device with blood samples from 74 patients in the Carle Foundation Hospital intensive care and emergency departments. The samples were taken at various times during the patients’ stay at the hospital, including those from 6 patients who did not recover and died. The results show the device returned results in about 30 minutes, and the sepsis indicators measured on the chip correlated positively with conventional lab tests and the patients’ vital signs.

“By measuring the CD64 and the white cell counts, we were able to correlate the diagnosis and progress of the patient, whether they were improving or not,” says postdoctoral researcher and first author Umer Hassan in a university statement. “We hope that this technology will be able to not only diagnose the patient but also provide a prognosis. We have more work to do on that.”

That work is being done in Bashir’s lab, as well as the start-up company Prenosis Inc. in nearby Champaign, Illinois. The company, founded by Bashir and co-author Bobby Reddy, licenses technology from the lab to develop lab-on-a-chip devices for point of care diagnostics. Reddy is Prenosis’s CEO and Bashir is the company’s chief scientist. Hassan also has an interest in the Prenosis.

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• Fund Created for Point-of-Care Diagnostics, Treatment
• FDA, Emulate to Test Organs-on-Chips for Drug Toxins

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