Despite all the encouraging advances in cancer therapy, the eradication of cancer cells or removal of tumours from patients is still largely a hit-or-miss proposition. One way to improve the chance of success is to use a combination of drugs with different fighting properties. However, delivering this into the core of tumours, where it works most effectively, can be a challenge.

Kheireddine el-Boubbou and co-workers from KAIMRC have now developed a porous type of iron oxide particles that can absorb a variety of drugs for use in cancer treatment. Because the particles are microscopic and made of a magnetic material, they have the potential to penetrate deep into the core of tumours to be used as carriers for controlled drug delivery.

To prepare the porous iron oxide particles, the researchers impregnated tiny porous silica balls known as acid-prepared mesoporous spheres (APMS) with iron chloride. These APMS have interconnected pores measuring 4–6 nanometers in diameter and were selected for their rigid framework, chemical inertness and good controllability. Next, the researchers used a sintering process to reduce the iron chloride to iron oxide. Finally, the silica that served as template for constructing iron oxide particles, was etched away using basic sodium hydroxide solution.

The researchers observed the iron oxide particles under a microscope and found that they all had bumpy surface and a porous interior. Further experiments revealed that the pores had relatively large volume, ideal for carrying cancer drugs.

The researchers were able to separate the iron oxide particles from water using a permanent magnet, indicating their potential to be manipulated by magnetic fields. They further tested the drug loading and release kinetics of the iron oxide particles using the hormonal anticancer drug, Tamoxifen, and two well-known hydrophilic chemotherapeutic drugs, doxorubicin and daunorubicin. Their results showed that one milligram of iron oxide particles could carry up to 165, 227 and 235 microgram of Tamoxifen, doxorubicin and daunorubicin, respectively. They also found that the drugs would be released when the environment became slightly acidic, much like that surrounding cancer cells.

The researchers were able to use the drug-loaded iron oxide particles to kill breast and colorectal cancer cell lines. When applied on breast tumours, the iron oxide particles would accumulate deep inside the core, thus demonstrating their potential for use in cancer therapy.

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