We've been told in song for decades that diamonds are a "girls best friend".  What about "nanodiamonds"?  Well, a gift of a nanodiamond may not be the best way to win the heart of a girl, but should you ever need targeted, sustained delivery of a drug to your heart, then nanodiamonds might be just the thing.  The LabMan talked to Dean Ho, JALA Editor and Assistant Professor of Biomedical and Mechanical Engineering at the Robert R. McCormick School of Engineering and Applied Science, Northwestern University, about his research into nanodiamonds. 

Dean told us that nanodiamonds are a byproduct of the explosive technology used to mine diamonds, essentially tiny fragments of diamonds left over in the soot from blasting diamonds from the ground.  As such, they are relatively inexpensive.  These 4-6 nm particles look (at the microscopic level) like tiny, angular soccer balls.  Composed completly of carbon, their surfaces are very hydrophyllic and provide excellent bonding points for other molecules, such as small molecule and protein drug entities.  They are also very compatible with being inside the body of a carbon-based life form, like us. 

Once cleaned up from the mining soot with an acid wash, sonication and centrifugation, they are relatively uniform in size and have activated carboxyl surfaces ideal for bonding other chemical entities.  These bonds break very slowly over time in an aqueous environment, thus making nanodiamond particles attractive vehicles for the sustained delivery of drugs in the body.  Deans research group has successfully bound both hydrophyllic and hydrophobic small molecules to nanodiamonds, as well as proteins such as insulin, DNA for gene therapy and antibodies for wound healing applications. 

One of their primary therapeutic areas of focus is cancer treatment, where often very toxic small molecules need to be delivered in a sustained way to specific areas of the body.  General overall dosing of the patent with these drugs, such as doxorubicin, can be very harmful to the body, but sustained microdosing to targeted areas is much better tolerated.  The effective mode of binding small molecules seems to be electrostatic attraction.   Binding and stability of DNA is accomplished using a polymer coating.  Current gene delivery technology tends to swing between high efficiency with high toxicity or low efficiency with low toxicity.  Nanodiamond delivery hold promise for both high efficiency with low toxicity. 

Future directions of research are aimed at making implantible devices containing nanodiamonds.   An example would be a tiny patch to be placed on the heart of a patient after open heart surgery to slowly release anti-inflammatory, anti-pain or anti-scarring agents to the heart tissue, to mitigate common post-operative complications. 

Until next time,

Domo Arigato, Mr. Roboto!