Nanotherapy for AMD

The use of green gold nanoparticles may have a place in the therapy of cancer and ophthalmic diseases, according to a study presented at this year's meeting of the Association for Research in Vision & Ophthalmology (ARVO). Kattesh Katti, PhD, from Nanotechnology, Physics, and Radiology, University of Missouri, Columbia, US, who conducted the study, said that this was because of the affinity of the gold nanoparticles for leaky vasculature.

"The nanoparticles are focused and given a sense of direction so that, when injected into the tumours, they can provide morphologic information and possible directions for new therapeutic modalities," Dr Katti said.

The level of amplification of the therapeutic payload that the use of gold nanoparticles (with about 200 000 atoms) provides is not possible with conventional therapy, he said, using bevacizumab (Avastin; Genentech) as an example. "Super-Avastin" would have hundreds of units of bevacizumab in one particle: in age-related macular degeneration (AMD), a potent dose of a drug such as bevacizumab might allow intraperitoneal injections rather than invasive intraocular injections. In rats, this therapy has shown 80–95% blood vessel shrinkage, according to Dr Katti, a figure that was corroborated histologically.

"Nanoparticles . . . have an affinity for leaky vasculature in AMD and cancer, and there is a high affinity of biocompatible gold nanoparticles toward the vasculature [that] can be used for site-specific delivery and localization," Dr Katti said. "In addition, gold nanoparticles carry substantially increased therapeutic payloads compared with conventional therapy and they provide opportunities for designing new pharmaceuticals for treating cancer, AMD, and related diseases."