Sep 26, 2007
Topical Review – carbon nanotubes
Since carbon nanotubes were discovered in 1991, researchers have been exploring their potential for applications at the interface between biological and materials sciences. Recent progress in chemical modification and bio-functionalization methods has made it possible to generate a new class of bioactive carbon-nanotubes that are linked to proteins, carbohydrates or nucleic acids. The aims of such functionalization include developing nanoscale bioelectronics systems and biosensors and trials of the use of carbon nanotubes for targeted bio-delivery applications to convey peptides or other genetic materials to cells.
Our research focuses on the ultimate challenge in the design of biosensors: the ability to detect and study single molecules. By drawing on the properties of carbon nanotubes and advances in nanoscale fabrication and characterization, we are exploring new avenues for achieving single-molecule detection. As an example, every atom in a single-walled carbon nanotube lies on the nanotube’s surface and, therefore, surface adsorption of any molecule will alter the optical properties of the nanotube. Consequently, nanotube-based optical sensors are potentially capable of exquisite detection sensitivity at the molecular level. By using near-field optical scanning microscopy to characterize carbon-nanotube-DNA hybrids, we are quantifying the changes in the optical properties of carbon nanotubes that occur during the subtle biomolecular processes involved in molecular binding.
The main outcome we expect from this research will be development of optical DNA-detection methods that use oligonucleotide-functionalized carbon nanotubes as biosensors to provide real-time, label-free quantification of DNA and a straightforward approach to high-sensitivity and multiplexed detection of DNA. Along the way, we will cultivate a fundamental understanding of the interactions between nanoscale materials, such as carbon nanotubes, and biological molecules through the application of our combined skills in physics, chemistry and biology.
About the author
Dr Wenrong Yang is a University postdoctoral research fellow at the University of Sydney who is collaborating with A/Prof Filip Braet, Dr Pall Thorsdarson, Prof Justin Gooding (UNSW), Dr Maxine McCall and Dr Minoo Moghaddam (CSIRO) to create biomodified carbon nanotubes and biosensors and to develop novel techniques in scanning probe microscopy.