Researchers Tightly Control Gold Nanoparticle Size | Chemical & Engineering News
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Web Date: March 16, 2012

Researchers Tightly Control Gold Nanoparticle Size

Drug Delivery: Spheres could carry cancer drugs and reduce chemotherapy’s side effects
Department: Science & Technology
News Channels: Materials SCENE, Nano SCENE, Biological SCENE
Keywords: drug delivery, cancer, chemotherapy, cisplatin, nanoparticles, nanomaterials
Loaded Nanoparticles
A gold spherical nanoparticle grasps thousands of cisplatin molecules, each carried by polyethylene glycol linkers.
Credit: Inorg. Chem.
Structure of cisplatin bound to nanoparticles
Loaded Nanoparticles
A gold spherical nanoparticle grasps thousands of cisplatin molecules, each carried by polyethylene glycol linkers.
Credit: Inorg. Chem.

Gold nanoparticles could improve the effectiveness of cancer drugs, many researchers think, by selectively carrying the drugs to tumors. But many synthesis methods yield particles with a broad range of sizes, which probably would not pass muster with regulators. Now researchers have developed a method for making cisplatin-loaded gold spheres with tightly controlled size distribution (Inorg. Chem., DOI: 10.1021/ic202197g).

Side effects often limit patients’ doses of chemotherapy drugs. Researchers have shown in the lab that affixing a drug like cisplatin to nanoparticles allows them to target tumors selectively.

The nanoparticles help the drugs target tumors selectively, because, explains Nial Wheate of the University of Sydney, in Australia, who led the study, “Cancer cells are a bit like dodgy house builders.” They grow so quickly that gaps riddle their vasculature and lymphatic system, he says. Those holes allow nanoparticles of appropriate size to slip in. Inside a cancer cell, Wheate’s group has shown, the acidic intracellular environment releases the particles’ platinum-based drugs (J. Am. Chem. Soc., DOI: 10.1021/ja908117a).

Wheate and his team refined a previously developed procedure for making gold nanoparticles with strict size control; they made particles with diameters of 25, 55, and 90 nm. Using dynamic light scattering and atomic force microscopy, the researchers found that the diameter varied by less than 9% in each batch. To achieve those results, the team made adjustments to the previous synthesis method, including optimizing the concentrations of the reactants and taking special care to exclude water.

The researchers attached cisplatin to the gold particles using polyethylene glycol linkers, so that each of the 25-nm nanoparticles carried around 800 drug molecules and the larger particles carried thousands.

Now Wheate and his team are attaching their nanoparticles to BBR3464, an experimental multiplatinum drug that’s highly effective but also very toxic. It stands to greatly benefit from a nanoparticle delivery system, he says.

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Aaron Thomas (March 16, 2012 10:08 AM)
I worked on a project where I was able to get monodisperse, 2 nm gold nanoparticles using dodecanethiol.... I did this work under a Dr. Metzger at the University of Alabama in Tuscaloosa. Although it was for an REU project and outside of my usual research I was doing at Georgia Southern in organic synthetic chemistry under Dr. Stallings ( one of THE finest quality professors I've had the distinct pleasure to work with) it was a fantastic project well worth the months of effort... It broadened my skill set immensely working in materials science/physical chemistry; ideas and skills I hope to bring with me into a Ph.D program and also into my work later in finding the cure for Alzheimer's Disaease. Thanks for sharing this fantastic article.

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