Lab-on-a-chip makes rapid assessment of immune system

Scientists from Nanyang Technological University, Singapore have developed a lab-on-a-chip system that identifies the health of a person’s immune system from a drop of blood within minutes.

immune system
Lab-on-a-chip by NTU scientists that can sort out white blood cells and analyse them to find out their health status (Image: NTU Singapore)

Using microfluidics and electrical sensors, the new chip from NTU Singapore was able to detect differences in the electrical properties of white blood cells taken from healthy and diabetic patients.

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According to NTU, the proof-of-concept device could one day help doctors to quickly gain insights into a person’s immune system and spot early signs of inflammation and infection that could signal the need for further in-depth tests. A prototype device and the engineering principles behind it were reported earlier in the year in Lab on a Chip.

Designed and built by Assistant Professor Hou Han Wei and Assistant Professor Holden Li from the School of Mechanical and Aerospace Engineering, their device, if successful in further laboratory and clinical assessments, could be turned into a portable device suitable for GP’s surgeries and polyclinics.

In a statement, Asst Prof Hou said the chip detects electrical differences between a healthy white blood cell and an unhealthy one. Abnormal white blood cells have been reported as an early biomarker for increased risk of cardiovascular diseases and also suggests an ongoing inflammation.

Using very tiny channels, the chip first physically separates the various blood cells by size into the different outlets. The isolated white blood cells are then run through a special channel where electrical impedance is measured for each cell at hundreds of cells per second.

The electrical impedance of an abnormal cell is usually higher than the impedance of a healthy cell, given an abnormal cell is larger in size and has different membrane properties.

From top left - Asst Prof Hou Han Wei, Asst Prof Holden Li, Research fellow Chayakorn Petchakup and Project manager Tay Hui Min (NTU Singapore)

White blood cells form a significant part of the body’s immune system, and a key type known as neutrophils is the first line of defence when infection or inflammation strikes.

“Our chips can isolate thousands of white blood cells from a single drop of blood and, within minutes, tell if these cells are electrically different from normal, which would be an indicator of whether there is a health issue to be further investigated,” Asst Prof Hou said. “More importantly, our process also does not use any chemical biomarkers or antibodies, which makes the assay cheap, easy to use, and that we can do further analysis on the same white blood cells we have already run through the chip.”

Asst Prof Holden Li said that the material used to make the new lab-on-a-chip is a common medical-grade polymer and is easily manufactured using existing machinery, and can be made into a desktop-sized machine for use in clinics.

“Our chip was designed for easy scale-up by companies, with an integrated system built from electronic components available on the market. Moving forward, we are looking to commercialise the technology with an industry partner, as we see that there are market demands –for a point-of-care device for doctors and as laboratory equipment for the study of neutrophils and drug screening,” Prof Li said.

The scientists added that they are doing more research on various electrical impedance levels and what each of them signifies, which will help build a reference library for an automated analysis.