  Porous structured Au colloids have been prepared from bulk nanoporous Au by
means of an element dissociation method. The microscopic techniques (scanning
electron microscope and atomic force microscope), UV-Vis spectroscopy and zone
diffusion method have been employed to study their morphology, optical property
and anti-microbial activity against Gram-positive and Gram-negative bacterial
strains, respectively. It is shown that the porous structured Au colloidal
suspension exhibit excellent optical and antimicrobial properties. The
noticeable features present in the optical studies are two Plasmon resonance
peaks at 477 and 546 nm with overlapping of these peaks at a wavelength of 520
nm. The morphology studies by SEM and AFM indicate that the Au colloids are rod
shaped with an assembly of skeletal pore and ligament structure. The analysis
of the antimicrobial activity testing reveals that the porous structured Au
colloids have greater inhibitory effect against the tested Gram-positive and
Gram-negative bacterial strains.
