Nanoscale sensor can penetrate cells

Researchers at the ARC Centre of Excellence for Nanoscale BioPhotonics (CNBP) have developed a nanoscale sensor that can help detect cytokines — molecules that play a critical role in cellular response to infection, inflammation, trauma and disease.

As explained by CNBP project scientist Guozhen Liu, Associate Professor at Macquarie University, cytokines are molecules secreted by the cells of the immune system. “The release of certain cytokines by the body is frequently symptomatic of a disease- or health-related issue, such as arthritis, inflammatory disorder or even cancer,” she said.

“Consequently, monitoring cytokine secretions at the cellular and subcellular level has enormous value in our understanding of basic physiology and how the body is actually working.”

Cytokine molecules have traditionally been difficult to measure and quantify due to their small size and their dynamic and transient nature, noted Associate Professor Liu. Now, however, the CNBP researchers have designed a sensor that is “so small that it can easily penetrate inside cells”, said Associate Professor Liu.

The sensor consists of a modified graphene quantum dot (or GQD) that allows ultrasmall amounts of cytokines to be identified in and around cells. “Moreover, unlike other sensors it only responds when the cytokine is present,” said Associate Professor Liu. “To this aim, we have connected GQDs to cytokine-sensing DNA molecules known as aptamers.”

Macquarie University Professor Ewa Goldys, deputy director at the CNBP, said the detection of cytokines in body fluids, cells, tissues and organisms is attracting considerable attention in the biomedical research field, with the ability to track cytokine levels in real time opening new ways to monitor body physiology. Furthermore, she said, the GQD sensing technology has potential widespread applications due to the universal nature of the sensor design.

“We see these graphene quantum dot sensors as being excellent candidates for many other biomedical applications such as DNA and protein analysis, intracellular tracking as well as for monitoring of other cell-secreted products in the body,” she said.

The study has been published in the journal Nanoscale.

Image caption: The cellular environment.