doi:10.1038/nindia.2013.177 Published online 30 December 2013
Researchers have produced thermo-responsive magnetic nanohydrogels that are capable of inhibiting tumour growth in mice . These nanohydrogels could be used for delivering anticancer drugs to cancer-affected organs such as the lungs.
Thermo-responsive hydrogels are promising because they dissolve in water below a certain temperature. This makes them excellent drug carriers which can release drugs when exposed to heat. However, the tumour-inhibiting potential of incorporating magnetic nanoparticles in such hydrogels had not been previously studied.
To explore this tumour-inhibiting potential, the researchers synthesized thermo-responsive magnetic nanohydrogels using poly (N-isopropylacrylamide), chitosan and iron oxide nanoparticles. They then probed the biocompatibility and biodistribution of the nanohydrogels in healthy mice and the anticancer activity of the nanohydrogels in tumour-bearing mice.
The nanohydrogels were injected into mice tumours and exposed to an external magnetic field. The heat generated by this magnetic field activated the nanohydrogels, which then caused the tumours to shrink. A double dose of the nanohydrogels suppressed tumour growth more than a single dose. In addition to being biocompatible, the nanohydrogels accumulated more in the lungs than in the spleens, livers, brains and kidneys of the mice, especially during the first hour after injection. This preferential accumulation of the nanohydrogels in the lungs may be exploited for treating deadly lung tumours.
Being a pH-sensitive formulation, drug release from the nanohydrogels would be greater in tumor tissue, which has a low pH. "The nanohydrogels loaded with anticancer drugs could be delivered via a non-invasive process to a target cancer tissue just by applying an external magnetic field," says D. Bahadur, a senior author of the study.