Biomedical nanotechnology gains pace

Until recently nanotechnologists -- scientists who build devices and materials one atom or molecule at a time -- concentrated almost entirely on electronics, computers, telecommunications, and materials manufacture. Now biomedical nanotechnology, in which bio-engineers construct tiny particles combining inorganic and biological materials -- is pushing to the forefront of this rapidly advancing field of science.

Dr Shuming Nie, professor in the Coulter Department of Biomedical Engineering at Emory university and the Georgia Institute of Technology and director of cancer nanotechnology at Emory's Winship Cancer Institute in the US, highlighted recent research at the 225th National Meeting of the American Chemical Society on 27 March.

"We believe biomedical nanotechnology will soon produce major advances in molecular diagnostics, therapeutics, molecular biology and bioengineering,"​ said Dr Nie. "Already scientists have begun to develop functional nanoparticles that are linked to biological molecules such as peptides, proteins and DNA."​

Nanoparticles assume special properties by virtue of their miniature size that distinguish them from larger particles, including changes in colour as they grow smaller and smaller. Because of their compact structure, nanoparticles emit light and can act as a fluorescent tag. Nie reports that this makes them highly suitable as contrast agents for magnetic resonance imaging (MRI), in positron emission tomography (PET) for molecular imaging in patients, or as fluorescent tracers in optical microscopy. Nanoparticles also have advantages over conventional dyes - they fade less quickly, they are less toxic to cells and they can be used in combination to create almost an infinite number of colours.

Although nanoparticles are similar in size to biomolecules such as proteins and DNA, human-made nanoparticles can be engineered to have specific or multiple functions. Bioconjugated quantum dots, consisting of different sized dots embedded in tiny beads made of polymer material, can be finely tuned to a myriad of different colours that can tag a multitude of different proteins or genetic sequences in a process called "multiplexing."

By chemically binding the quantum dots to particular genes and proteins, scientists, including Dr Nie, are developing molecular nanoprobes to rapidly analyse biopsy tissue from cancer patients, to monitor the effectiveness of drug therapy, as scaffolding in tissue engineering, and as "smart bombs" to deliver controlled amounts of drugs into genetically classified tumour cells.