Nanodiamonds Show Promise as Chemotherapy Boosters

A new study suggests that nanodiamonds--tiny particles of carbon--could serve as a promising new drug delivery approach for treating breast and liver cancer tumors that are resistant to chemotherapy.

Researchers at Northwestern University (Evanston, IL, USA) developed nanodiamond (ND) conjugated chemotherapeutic therapies to improve drug delivery to chemoresistant cancers, and examined their efficacy in mouse models of liver and mammary cancer. The researchers found that a complex of ND and doxorubicin (Dox) increased the efficiency of the cancer drug by a factor of 70, while still maintaining safety. The complex also overcame drug efflux and significantly increased apoptosis and tumor growth inhibition beyond conventional Dox treatment, in both the murine liver tumor and mammary carcinoma models.

The results suggest that ND-conjugated chemotherapy represents a promising biocompatible strategy for overcoming chemoresistance, since chemotherapeutic drugs can be bound tightly to the ND surface with a chemical bond, or temporarily with an electrostatic bond. These options can allow some drugs to do their job while still attached to the ND surface; other drugs have the potential to release on-site once they have reached the tumor, by attaching a unique matching chemical compound or an antibody to one end of the ND. The study was published in the March 9, 2011, issue of Science Translational Medicine.

"They're called truncated octahedrons, shaped like a soccer ball but the faces are more angled. It's the faces of the nanodiamonds that allow the drugs to bind tightly to their surface and release slowly,” said corresponding author Dean Ho, PhD, an associate professor of biomedical engineering. "The surface chemistry, coupled with the architecture of the surface, allows for a sustained interaction with drugs.”

Unmodified Dox treatment represents the current clinical standard for most cancer treatment regimens. It is an anthracycline antibiotic, administered intravenously as a hydrochloride salt, and works by intercalating DNA. Dox is commonly used in the treatment of a wide range of cancers, including hematological malignancies, many types of carcinoma, and soft tissue sarcomas.

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