17 January 2022
Nanotechnology shows great potential to improve cancer treatments, providing tiny vessels that can carry drugs to tumour sites and release them gradually. Now, KAIMRC researchers, Rizwan Ali and Mohamed Boudjelal, working with Kheireddine El-Boubbou at King Saud bin Abdulaziz University for Health Sciences, have developed magnetic nanostructures that can deliver the chemotherapy drug Doxorubicin (Dox) directly into cancer cells without harming healthy cells.
“Controlled drug delivery systems are a hot topic due to their promising ability to enhance the therapeutic efficacy of drugs,” says Boudjelal. “Our new iron oxide mesoporous magnetic nanoparticles (IO-MMNPs) are particularly attractive, due to their drug entrapment capabilities, low toxicity, and stability within the body.”
Producing nanoparticles of the perfect size and porosity requires meticulous laboratory work. “Controlling the physiochemical properties for effective therapeutic drug delivery is very challenging,” explains Ali. The team used an acid preparation technique to produce silica spheres with uniform pores. They then impregnated the spheres with iron nitrate, which fills the pores with iron. The silica was removed using a hot alkaline treatment, leaving porous iron oxide nanoparticles with large surface areas that can soak up and store Dox or other drugs.
“Our fabrication approach provided uniform spherical morphologies, high surface areas and large, controllable pore structures,” says Boudjelal.
The team performed in vitro experiments, treating cell cultures with either free Dox, Dox-infused IO-MMNPs, or ‘bare’ IO-MMNPs. These revealed that Dox was tightly held within the IO-MMNPs by electrostatic interactions, meaning that negligible amounts of the drug were released in the neutral pH environment of healthy cells. However, acidic environments such as those found in tumours caused more than half of the Dox to be released over a 24 to 48hour period.
The researchers’ microscope images showed IO-MMNPs gradually being enveloped within the cell cytoplasm, effectively delivering Dox to kill colon and breast cancer cells but not healthy cells. This indicates that nanoparticle treatments could greatly reduce the side effects caused by chemotherapy drugs.
Eventually, the team hope that their IO-MMNPs could be injected and guided towards tumour sites using magnetic fields. “Magnetic fields have excellent penetration in biological tissues,” explains Ali. “However, the delivery of nanoparticles using a magnetic field is still in its development phase. Before that, our immediate goal is to test our IO-MMNPs in live mouse models to evaluate their selective cytotoxic effect on different cancer types.”
El-Boubbou, K. et al. Iron Oxide Mesoporous Magnetic Nanostructures with High Surface Area for Enhanced and Selective Drug Delivery to Metastatic Cancer Cells. Pharmaceutics 13, 553 (2021).| article