Nanoparticles: wave of the future in diagnosis and therapeutics

The use of green gold nanoparticles may have a place in the therapy of cancer and ophthalmic diseases because ofthe affinity of the gold nanoparticles for the leaky vasculature in those diseases, according to Kattesh Katti,PhD, from Nanotechnology, Physics, and Radiology, University of Missouri, Columbia.

"The field of nanomedicine is an emerging medical modality that uses nanoparticles for diagnostic andtherapeutic applications," Dr. Katti said. "The nanoparticles are focused and given a sense of direction sothat, when injected into the tumors, they can provide morphologic information and possible directions for newtherapeutic modalities."

The level of amplification of the therapeutic payload that the use of gold nanoparticles (with about 200,000atoms) provides is not possible with conventional therapy, he said, using bevacizumab (Avastin, Genentech) as anexample. "Super-Avastin" would have hundreds of units of bevacizumab in one particle, he added. In age-relatedmacular degeneration (AMD), the potent dose of a drug such as bevacizumab might allow intraperitoneal injectionsrather than invasive intraocular injections. This therapy has been done in rats with AMD and there was agreat degree of blood vessel shrinkage-80% to 95%, according to Dr. Katti, and corroboratedhistologically.

Since nanoparticles are substantially smaller than a cell, they can be used to focus on small precancerouslesions by targeting unusual cells with nanoparticles with diagnostic capabilities, he said.

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