New sensors could lead to earlier lymphoma diagnosis

20 September 2019:

CNBP researchers have developed a new method of detecting multiple cytokines – the body’s messenger proteins – in very small volume samples, which could lead to earlier diagnosis of diseases such as lymphoma.

The work was published in a paper in the journal ACS Sensors.

“It could open the door to non-invasive diagnosis at early stage, as well as clinical applications such as monitoring treatments,” says Dr Lianmei Jang, one of the authors of the study and a biomedical engineer based at Macquarie University in Sydney.

Cytokines are a key part of the immune system which swing into action in the event of disease or injury.

That has made them a longstanding target by researchers keen to get a better understanding of how the body responds to infection.

It has always been a challenge, however, to simultaneously detect multiple cytokines in a single sample and this imposes significant limits on research.

Various cytokines perform different functions and can trigger other cytokines to realist in a complex network speaking a complex “language”.

“When you look at just one type of cytokine it is very difficult to tell what is going on between the cells,” Lianmei says. “If we can get to look at multiple cytokines we can understand better what is happening in the complex networks.”

Lianmei in the lab

And being able to detect the cytokines in such low concentration – as low as 5 picograms per millilitre – allows for diagnosis at a very early stage, she says.

Lianmei, working with Dr Yuling Wang’s team (AI of CNBP) developed the alternative detection approach using gold nanoparticles with surface-enhanced Raman spectroscopy (SERS) nanotags to target the cytokines used as biomarkers for lymphoma.

Raman spectroscopy is widely used in chemistry to identify certain molecules. In this case the Raman readers on the nanoparticles picked up the signals from the cytokines.

“The sensitivity of this technique that allows it to work in such low concentrations is down to the SERS nanoparticles,” says Lianmei.

The project took around 18 months and was a collaboration with CNBP colleagues Ivan Maksymov and Andrew Greentree, based at RMIT in Melbourne.

Journal: ACS Sensors

Publication Title: Sensitive and Multiplexed SERS Nanotags for the Detection of Cytokines Secreted by Lymphoma

Authors: Dan Li, Lianmei Jiang, James A. Piper, Ivan S. Maksymov, Andrew D. Greentree, Erkang Wang and Yuling Wang

Keywords: surface-enhanced Raman spectroscopy, nanotags, cytokine, multiplexed detection

Abstract: The sensitive and simultaneous detection of cytokines will provide new insights into physiological process and disease pathways due to the complex nature of cytokine networks. However, the key challenge is the lack of probes that can simultaneously detect multiple cytokines in a single sample. In this contribution, we propose an alternative approach for sensitive cytokine detection in a multiplex manner by the use of a new set of surface-enhanced Raman spectroscopy (SERS) nanotags. Typically, the new designed SERS nanotags are composed of gold nanoparticles as the core, tuneable Raman molecules as the reporters and a thin silver layer as the shell. As demonstrated through rigorous numerical simulations, enhanced Raman signal is achieved due to a strong localization of light in the 0.2-nm-thin, optically deep-subwavelength region between the Au core and Ag shell. Sensitive detection of cytokines is realized by forming a sandwich immunoassay. The detection limit is down to 4.5 pg mL-1 (S/N=3). The specificity of the assay is proved as negligible signals were detected for the false targets. Furthermore, multiple cytokines are simultaneously detected in a single assay from the secretion of B-lymphocyte cell line (Raji) after concanavalin A (Con A) stimulation. The results indicate that our method holds a significant potential for sensitive and multiplexed detection of cytokines and offers the opportunity for future applications in clinical settings.