Insects inspire a first in nanosensor technology

Taking inspiration from the structure of insect wings, RMIT University researchers have become the first to fabricate batches of nanoscale sensors on the tips of optical fibres, in a crucial step towards mass manufacture of the technology.

Led by Professor Arnan Mitchell from RMIT and Dr Paul Stoddart from Swinburne University, the team used a technique similar to that used for stamping out vinyl records - nanoimprint lithography - to demonstrate the parallel fabrication of nanoscale sensors on optical fibre tips for the first time. The research, which has been featured as the cover story in the journal Advanced Materials, has a range of potential applications from medicine and biotechnology to sensing environmental contaminants.

Lead investigator Dr Gorgi Kostovski, from RMIT’s Platform Technologies Research Institute, said because optical fibres were about the width of a human hair, they were ideally suited as platforms for building tiny sensors.

“Sculpting features at the nano level is difficult but nature has already done the most intricate work for us, with some insect wings featuring nano-sized elements that act to minimise reflections and reduce their visibility to predators,” he said.

“Using the transparent wing of a cicada as a source of naturally occurring nanofeatures, we have been able to copy these textures onto fibre tips. Previously, it would take up to an hour to build just one nanosensor.

“In this research, we devised a technique enabling us to employ the cicada wings for large-volume manufacture, building up to 40 nanosensors at a time. While more work needs to be done to enable economical large-scale manufacture of nanosensors, this demonstrates a low-cost and accessible way forward.”

This research was funded through a National Health and Medical Research Council Development grant to develop intravenous sensors based on a combination of advanced manufacturing, fibre optics and nanotechnology.

The small cross-section of optical fibres makes them particularly useful as platforms for sensing, potentially offering access to difficult and sensitive environments such as hypodermic needles inserted into blood vessels.

“We hope our work will stimulate further research into this exciting field, and make optical fibre tip sensors a widely used technology,” Dr Kostovski said.