White blood cells can easily detect and capture the tiny nanotube like structures making it difficult for the researchers trying to use them as vehicles, to deliver drugs inside the body in a targeted way.
These nanotubes also prompt severe immune reactions.
The research team is now using nanohorns to deliberately push immune system into action.
They believe that this uninvited immune response can push the body into fighting a disease or cancer more effectively.
For the study, Alberto Bianco and Helene Dumortier at the CNRS Institute in Strasbourg, France, in collaboration with Maurizio Prato at the University of Trieste, Italy, gave carbon nanohorns to mouse white blood cells in a Petri dish. The macrophage cells' job is to swallow foreign particles.
They found that after 24 hours, most of the macrophages had swallowed some nanohorns and also started to release reactive oxygen compounds and other small molecules that give an indication to other parts of the immune system to become more active.
By filling the interior of nanohorns with particular antigens, like ice cream filling a cone, the team believes that they can adjust the immune response to fight a particular disease or cancer.
"The nanohorns would deliver the antigen to the macrophages while also triggering a cascade of pro-inflammatory effects," New Scientist quoted Dumortier, as saying.
"There is still a long way to go before this interesting approach might become safe and effective," said Ruth Duncan at Cardiff University, UK.
"Safety would ultimately depend on proposed dose the frequency of dose and the route of administration," she added.
"This process should initiate an antigen-specific immune response," she added.
Dumortier said that the results so far suggest that nanohorns are less toxic to cells than normal nanotubes can be.
"No sign of cell death was visible upon three days of macrophage culture in the presence of nanohorns," she added.