Cover Image from Small, a prestigious journal devoted to emerging nanotechnologies
A photomicrograph of multiwalled carbon nanotubes (CNTs) implanted within muscle. The tissue reaction to the nanomaterials (grey) is minor and the surrounding muscle is preserved.
Researchers at the Bionics Institute, with colleagues from the University of Wollongong and University of Melbourne, have recently reported on the biocompatibility of carbon nanotubes (CNTs) and their potential use within advanced bionic devices.
CNTs have diameters in the order of tens to hundreds of nanometres (one nanometre is a millionth of a millimetre). They possess unique and useful properties, including excellent electrical conductivity and high tensile strength. These properties make CNTs a promising material for the next generation of neural-computer interfacing electrodes.
CNTs may be able to stimulate nerve cells with a more intimate and localised electrical field that uses less power than conventional electrodes. CNT electrodes may thus give bionic ear recipients better perception of sound with smaller devices, and provide a promising possibility for retinal implants or deep brain stimulators.
There has been some concern regarding the safety of nano-materials, particularly for therapeutic use. Therefore, an important first step is to investigate the safety and efficacy of proposed composite nano-materials for future neural prostheses.
This study reported on:
- biocompatibility of composite materials containing CNTs to determine whether they can be used safely in a physiological setting
- changes to tissue following long-term exposure to CNTs
- the growth of biological material on the surface of these chronically implanted nano-materials
Characterising the extent of tissue ‘build-up’ is important as it limits the performance of devices using electrodes to communicate with nearby nerves.
Dr David Nayagam
led this particular study within the Bionics Institute, as part of a collaboration with the ARC Centre for Excellence for Electromaterials Science (ACES) headed by Prof Gordon Wallace.
“Our study showed that there was a minimal inflammatory and local foreign-body response to the CNTs when they were embedded within a biocompatible polymer sheet to form an electrode-like array”, he said.
“Our results are encouraging and suggest that this nano-material should be considered for further investigation and a potential component of high-fidelity bionic devices. We believe these data will inform future work in the emerging field of nano-bionics within our Institute, as well as around the world”.