The team’s paper, entitled Nanoparticle Vesicle Encoding for Imaging and Tracking Cell Populations, is published in the leading life sciences journal Nature Methods today (Sunday, September 14).

Working in collaboration with colleagues from the Broad Institute of MIT and Harvard (Cambridge, Massachusetts, USA), the Institute for Materials Research at Leeds University, and General Electric Healthcare, The Maynard Centre, Cardiff, the team found one of the key advantages of their method is that the cells ‘choose’ their own barcode depending on their physical state and therefore cancer cell barcodes appear different from healthy cells when examined through high-throughput microscope imaging.

The paper’s lead author, Professor Paul Rees (pictured) of Swansea University’s College of Engineering, said: “The ability to analyse collective behaviour within a cell population is crucial to the understanding of health and disease in the human body.

“However, the inability to accurately identify, track and measure thousands of single cells through using high-throughput microscope imaging has impeded dynamic studies of cell populations.

“We have demonstrated the unique method of labelling cells by colour-coding and generating a large number of unique digital codes, which enable us to immediately see a cell’s identity and allows us to track single human cells.”

The new method works because cells absorb nanoparticles as they take up nutrients from any surrounding fluid and then encapsulate them in a protective membrane, which means they do not appear to alter the cells’ behaviour.

By introducing three different colours of nanoparticle to the cell population the colour pattern generated is unique enough to act as a barcode allowing researchers to distinguish each individual cell in a large population. Also as the number of nanoparticles in the cell does not change, the same cell can be identified after much longer time periods than has previously been possible.

As the number of nanoparticles that a cell takes up is dependent on the cell state this method allows the identification of mutated cells in a large population because the barcode of these cells will have a different pattern than healthy cells.

Dr Anne Carpenter, director of the Imaging Platform at the Broad Institute, added: “Uniquely identifying and tracking individual cells within a popu­lation is incredibly powerful. Cell-tracking software is notoriously error-prone and yet tracking cells by eye in long movies is incredibly tedious.

“The approach developed here allows the cells to physically carry a barcode as they move around, making the tracking problem much more feasible. It takes a lot of pressure off of image analysts and enables long-term examination of cancer cell populations.”

This is a significant step in the development of tools to study the evolution of large cell populations. Looking ahead, this method will allow researchers to observe the progression of individual cells to a cancerous state or to study the evolution of stem cells into the mature cells that make up the human body.

The team’s work was funded through two grants from the Engineering and Physical Sciences Research Council (EPSRC), one of which enabled Professor Rees to go on sabbatical to the Broad Institute of Harvard and MIT (Boston), collaborators on the paper and where part of the research work was done. The EPSRC grant on Nanoparticle Cytometrics  funded the research.

The University’s Centre for NanoHealth is also funded by the European Regional Development Fund (ERDF) through the Welsh Government.

Notes:

The Centre for NanoHealth (CNH) at Swansea University offers access to more than 50 academic staff from the Colleges of Medicine, Engineering and Science, Health Board (NHS) clinicians, and industry. This 1600m² purpose build open access facility provides a technology and innovation base for SMEs in Wales and beyond. To date CNH has initiated many collaborative projects with industry and other HEIs realising more than £15 million further investment.

The Centre is a member of several global nanohealth networks including leading The Celtic Alliance for NanoHealth, the Alliance for NanoHealth, ETP nanomedicine and is a founding member of the Health Science and Technologies Collaborative Innovation Centre with Soochow University and Biobay in Suzhou, China.

Believed to be Europe’s first Centre for NanoHealth, the circa £22 million project was funded through £10 million from the European Regional Development Fund through the Welsh Government, Swansea University, Abertawe Bro Morgannwg University Health Board, Welsh Government Department for Health and Social Services and the Private Sector. Visit www.swansea.ac.uk/nanohealth.