Using Magnetic Field to Deliver Nanomedicines

Scientists have devised a novel way to concentrate nanoparticle-based drugs in neoplastic tissues with the help of a magnetic field, reports the University of Buffalo Reporter:

A nanoparticle-based drug-delivery concept in which an applied magnetic field directs the accumulation in tumor cells of custom-designed, drug-filled nanocarriers has been demonstrated by UB researchers.
The new approach, recently published in Molecular Pharmaceutics, may lead to treatments that exploit the advantages of photodynamic therapy (PDT) and that have the potential to reduce drug accumulation in normal tissues.
The in vitro results showed that magnetically guided delivery to tumor cells of these customized nanocarriers allowed for more precise targeting, while boosting cellular uptake of the PDT drugs contained inside them.
“This is a novel way to enhance drug delivery to cells,” said Paras Prasad, executive director of UB’s Institute for Lasers, Photonics and Biophotonics, SUNY Distinguished Professor in the Department of Chemistry, College of Arts and Sciences, and co-author on the paper.
“The externally applied magnetic field acted as a kind of ‘remote control,’ directing the nanocarriers to the targeted area in the cell culture,” he said.
Once the magnetic field was applied, the concentration of drug inside the tumor cells in the target area increased.
“We have shown that we can use magnetophoretic control to deliver PDT drug to tumor cells, resulting in increased accumulation inside those cells,” explained Tymish Ohulchanskyy, postdoctoral research scholar with the institute…
According to Prasad, photodynamic therapy is one of the most promising treatments for cancer; it’s also being investigated as a treatment method for cardiovascular, dermatological and ophthalmic diseases.
PDT exploits the propensity of tumors to retain higher concentrations of photosensitive drugs than normal tissues. When exposed to laser light, these drugs generate toxic molecules that destroy the cancer cells…
“The magnetically guided drug delivery would allow for the use of lower concentrations of the drug to deliver a therapeutic dose, thus significantly reducing the amount of PDT drug that accumulates in normal tissue,” said Prasad.
The UB team achieved these results with a novel nanocarrier system, developed from polymer micelles, which are nanosized, water-dispersible clusters of polymeric molecules.
Prasad explained that polymeric micelles are excellent nanocarriers for PDT drugs, which are mostly water-insoluble.
Along with the photodynamic drug, the UB researchers encapsulated inside the nanocarriers iron oxide nanoparticles, which allowed them to respond to externally applied magnetic fields.
In the experiments, nanocarriers were shown to be efficiently taken up by cultured tumor cells in the area exposed to the magnetic field, as demonstrated by confocal microscopy.
While the team has demonstrated this concept with PDT drugs, Prasad said the technique would be useful in delivering gene therapy, chemotherapy or practically any kind of pharmaceutical treatment into cells.

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