Research Highlight

Tunable nano drug carrier

doi:10.1038/nindia.2015.14 Published online 30 January 2015

Researchers have synthesized drug-modified gold nanoparticles that can slowly release a commercially available antibiotic called clavam1. The slow drug release is enough to kill disease causing bacterium Escherichia coli, making it a potential way of treating bacterial infections with reduced drug-induced toxic effects.

Clavam, a mixture of amoxicillin and potassium salt of clavulanic acid, kills a wide variety of disease-causing bacteria. However, at elevated doses, clavam has been shown to cause hepatitis, renal dysfunction and fatigue. Drug carriers based on nanoparticles are promising for minimizing such side effects, but nanoparticle synthesis requires using toxic chemicals.

The researchers synthesized gold nanoparticles using solutions containing commercially available clavam. They then probed these gold nanoparticles to release clavam by exposing them to glutathione, a cellular antioxidant that protects cells against the harmful effects of reactive oxygen species.

The scientists found that the amount of clavam release from the gold nanoparticle surfaces could be tuned by simply varying the concentration of glutathione. They found that higher the glutathione concentration was, faster the rate of clavam release was.  Release of clavam molecules caused the nanoparticles to aggregate; this reduced the absorption intensity, as the aggregates scattered more light than individual nanoparticles.

When exposed to human breast epithelial cells, the nanoparticles did not induce any toxic effects.


1. Manju, V. et al. Tunable release of clavam from clavam stabilized gold nanoparticles — design, characterization and antimicrobial study. Mater. Sci. Eng. C. 49, 500–508 (2015)