How it works
The biosensor is the latest adaptation of microfluidic lab-on-a-chip technology developed in RMIT’s MicroNano Research Facility.
A microfluidic chip contains tiny channels, pumps and processors, enabling precise and flexible manipulation of fluids. Essentially, microfluidics does for fluids what microelectronics does for information - integrating vast quantities of tiny processing elements into a small chip that is portable, fast and can be produced quickly and efficiently.
The new cost-effective and scaleable technology is lightweight and portable, combining microfluidics with nanophotonics.
Compatible with traditional microscopes, the biosensor is a thin glass slide coated with a gold film, perforated with billions of tiny nanoholes arranged in a specific pattern. These nanoholes transmit a single colour of light, due to an optical phenomena known as the plasmonic effect.
By observing the colour transmitted, researchers can determine the presence of minute quantities of specific chemicals on a slide without any external labels. This detection method enables the continuous monitoring of the chemicals produced from a single cell in real time.
The nanophotonic sensor is coupled to a microfluidic integrated circuit with fluid channels about the size of a human hair. The circuit includes valves to isolate the cell and concentrate its secretions, and systems to regulate the temperature and humidity to sustain the cell.
The work is a collaboration between the laboratory of Bionanophotonic Systems at EPFL, Switzerland, the Integrated Photonics and Applications Centre in the School of Engineering at RMIT and Ludwig Institute for Cancer Research, Switzerland.
RMIT microfluidic chips have been pivotal in enabling research across a range of areas - from water quality monitoring to the development of point-of-care blood tests for suspected heart attacks that could deliver results while a patient is still in an ambulance.
The paper, “Label-free optofluidic nanobiosensor enables real-time analysis of single-cell cytokine secretion” is published in Small (DOI: 10.1002/smll.201800698).