Nanodiamonds are much smaller than typical diamonds, at about four to five nanometers in diameter, have the shape of very tiny soccer balls, and are byproducts of mining and refining operations. In recent research, they have been found to have potential cancer treatment properties, and may also be used for dental implants. Recently, scientists found yet another application for the tiny diamonds — as biosensors and drug delivery carriers that can penetrate cells without damaging them.

The study used fluorescent nanodiamond particles (NDPs) in particular, which are a “highly suitable material for the construction of probes capable of sensing biomolecules ranging from proteins to DNA," team coordinator Milos Nesladek, also a principle scientist at the Institute for Material Research, Imec, in Belgium, told Such a probe, placed in a cell, could detect and gather information about biological processes in nano-scale, especially important in identifying pre-cancerous changes. NDPs are highly biocompatible and able to stay inside cells for long periods of time without affecting cellular mechanisms. They are non-invasive, meaning they can penetrate cell membranes without damaging the cell’s functions.

The importance of NPDs, as emphasized by this study, lies in their ability to both detect pre-cancerous changes in the cell and to work to fix them. Biomolecules can be attached to the NDP surface, and can be carried into the cell to measure and alter biological components inside the cell. This type of drug delivery allows the “release of drugs in the cells with unprecedented details,” Fedor Jelezko, director of the Institute of Quantum Optics at Ulm University in Germany, told

This isn’t the first time that scientists have tested the efficacy of nanodiamonds in drug delivery applications. The Drexel Nanomaterials Group calls nanodiamond power “one of the most promising carbon nanomaterials for drug delivery applications…[they] offer a large accessible surface and tailorable chemistr; have unique optical, mechanical, and thermal properties; and are non-toxic.” In 2011, an associate professor of biomedical engineering and mechanical engineering at Northwestern University completed a study that found nanodiamonds effective in fighting difficult-to-treat cancers. Dean Ho and a team of researchers bound a typically lethal amount of a chemotherapy drug with nanodiamonds, and applied it to tumors in mice. The tumors lessened significantly, increased survival rates, and did not have any serious toxic effect on tissues.

Though the work appears to be promising to many, other scientists are concerned that this type of drug delivery would not be entirely effective in humans: “Although there have been numerous convincing experiments showing that nanodiamonds can carry active anti-cancer drugs in culture cells and even in mice, it is very unlikely that it will be ever used in humans, mostly because the diamond is so inert that it cannot be degraded and therefore cannot be easily eliminated by the body,” a physics professor at ENS Cachan François Treussart told

The researchers for the most recent study, who were working for the EU-funded project Dinamo, will continue to test NDP probes. Though they primarily studied the method in breast cancer and colorectal cancer, they hope to begin applying it to a wide range of other cancers, and to potentially detect cancer stem cells.