Self-guide nanomotor delivers, according to Dutch study
The nanosized polymer was loaded with platinum nanoparticles and moved along a gradient of hydrogen peroxide. It takes its cue from bacterial movement towards chemicals, so-called chemotaxis.
We previously showed that decomposition of fuel by the entrapped catalyst produces a rapid discharge of gases propelling the vehicle forward, explained Daniela Wilson, molecular chemist at Radboud University Nijmegen, the Netherlands, and senior author of the study in Angewandte Chemie.
The new structure displayed motion towards high hydrogen peroxide concentrations, not only in a microfluidic device with an artificial chemical gradient, but also in the presence of hydrogen peroxide-secreting white blood cell (neutrophils).
Hydrogen peroxide is overproduced by tumour cells and in wounded tissue. A drug delivery system that could autonomously move between cells and hunt out the hydrogen peroxide source would allow for more precise drug delivery.
“Our nanomotor system loaded with anticancer drug was able to sense the presence of fuel secreting cells, self-propel and self-guide their motion towards them, even when the gradients were very low. Active locomotive nanometer scale vescular carriers are therefore promising for various areas of medicine, such as drug delivery, cancer treatment and diagnosis, wound healing and tissue generation,” Wilson explained.
Platinum loaded
The soft polymer nanomotor is loaded with platinum, which converts hydrogen peroxide into oxygen, which propels the tiny machine. The device is around 300 nanometres in diameter, whereas red blood cells are typically 6000 to 8000 nanometres.
“They could move freely in blood flow,” noted first author Fei Peng, and their small size makes them “suitable for delivering drugs to cells.” The hydrophobic anti-cancer drug doxorubicin is believed to locate in the polymer membrane and its inner compartments.
“Our next step is to develop biocompatible locomotive delivery systems and demonstrate their efficiency of release in tumour models and in vivo,” says Wilson.
“If you pop a pill the drug has to go through your whole body and diffuse to the infected area. That means the drug gets diluted, going to all places in your body, and it is a slower process,” said Ayusman Sen, nanomotor researcher at Penn State University in the US.
“A self-propelled particle is the holy grail of drug delivery systems. You then have a targeted system that can sense where the drug needs to be delivered.”
This group has combined several capabilities in the one device, that’s what is new here, adds Sen. “They have a system that you can load up with a drug, this system can be set in motion by catalysis and it can be directed to a particular spot.”
http://onlinelibrary.wiley.com/doi/10.1002/ange.201504186/full
