Research Highlight

Antibiotic aid for nanoparticles

doi:10.1038/nindia.2009.82 Published online 16 March 2009

An antibiotic has been used to produce gold nanoparticles. Known as cephalexin, the antibiotic triggers the formation of two well-separated populations of gold nanoparticles.

The nanoparticles have been found to be capped by the antibiotic thus making it a potential drug delivery candidate, where gold plays the role of a carrier as well as an optical probe.

Binding the surfaces of gold nanoparticle with drug molecules is attractive for several biomedical applications. Conjugating drug molecules, especially antibiotics, on metal nanoparticles remains a complex chemical synthesis. To overcome this challenge, the researchers used a novel one-pot synthesis to produce antibiotic-capped gold nanoparticles.

They diluted the antibiotic cephalexin and chloroauric acid and mixed them. The antibiotic reduced chloroauric acid to form nanoparticles. Two distinct populations of gold nanoparticles emerged at the lowest reaction temperature of 15ÂșC. Various functional groups on the antibiotic molecules might have a significant role in this process.

The big clusters (about 30 nm) are surrounded by a large number of smaller particles. The larger clusters (average diameter about 30 nm) at this temperature seem to be a collection of smaller particles (about 1-3 nm). "Our method doesn't use any harmful chemicals," says lead researcher Pankaj Poddar. These antibiotic-capped gold nanoparticles show much enhanced antibacterial activities, which could prove handy to combat multi-drug resistant (MDR) bugs, he adds.


  1. Jagannathan, R. et al. In Situ Observation of Antibiotic Mediated Concurrent Growth of Two Distinct Homogeneous Populations of Gold Nanoparticles in Solution Phase. J. Phys. Chem. C. 113, 3478-3486 (2009)