Washington, October 2 : Purdue University researchers have shown that it is possible to use nanoparticles for delivering treatments to injured brains and spinal cord cells.
Richard Borgens, a researcher at the School of Veterinary Medicine's Center for Paralysis Research and Welden School of Biomedical Engineering, says that he has already used silica nanoparticles coated with a polymer to target and repair injured guinea pig spinal cords.
Describing his research in a research paper, being published in the October edition of the journal Small, the researcher said that his team used the coated nanoparticles to deliver both the polymer and hydralazine to cells with secondary damage from a naturally produced toxin.
In their previous research, Borgens' group had used the polymer polyethylene glycol (PEG), which specifically targets damaged cells and seals the injured area to reduce further damage, to treat rats with brain injuries and dogs with spinal cord injuries.
For that research, the researchers had mixed PEG with saline, and injected into the subjects.
"Composition and concentration limited how much PEG we could get to the injury. If you change the composition to make the PEG more potent, it produces ethylene glycol, the poison in antifreeze. If you change the concentration of PEG in another way, the solution becomes syrupy and difficult to inject," Borgens said.
Thus, Borgens added, the research team turned to silica nanoparticles for their latest study.
"These particles are so tiny they can't be seen with a regular microscope. They are about the size of a large virus. So you can inject as many as you need. And they are safe inside bodies," the researcher said.
In the first study, the researchers coated the nanoparticles with PEG to treat guinea pig spinal cord injuries, and the treated spinal cord cells showed improved physiological functioning.
In the second study, they added both PEG and hydralazine, an antihypertension drug, to mesoporous silica nanoparticles with pores that could hold the drug so that it could be delivered to the damaged cells.
The hydralazine was added to fight off secondary damage to cells that occurs after the initial injury.
"When cells are injured, they produce natural toxins. Acrolein is the most poisonous of these toxins. It's an industrial hazard for which hydralazine is an antidote," Borgens said.
The researchers also introduced acrolein into cells, and treated them with different combinations of hydralazine and/or PEG delivered by the mesoporous silica nanoparticles.
Borgens said that the treatment was found to restored disrupted cell function caused by acrolein.
Based on their observations, the researchers came to the conclusion that the use of nanoparticles to deliver both PEG and hydralazine increased the effectiveness of earlier PEG-only treatment by controlling and concentrating release of the drug and the polymer, producing a dual treatment and prolonging the treatment's duration.
Borgens said that the objective behind his research was to improve the quality of life of the people who had suffered head or spinal cord injuries.
"All ambulances should have PEG on board. It can probably save thousands of people from more severe head and spinal damage," he said.
He and his colleagues are now testing the PEG/hydralazine treatment on rats with brain injuries, and the researchers hope to test the treatment on naturally injured paraplegic dogs by the end of the year.