A research tam at the Stanford University School of Medicine has developed gold-centered nano-spheres that is safe when delivered in two ways in a mouse. This toxicology study could lead to human testing for cancer detection.
According to Sanjiv Sam Gambhir, professor of radiology and senior author of the study, the lack of toxicity in mice shows the nano-particles could be safe for human use as well. Detecting cancer such as colorectal cancer in the initial stages enhances chances of survival. Colonoscopy has reduced colon-cancer death. But this form of detection relies on the human eye allowing for many misses.
The present research reveals the safety of tiny gold balls coated with materials that can be identified with high sensitivity, and covered in transparent silica shells and then attached to polyethylene glycol molecules to render them bio-friendly. Molecules tracking cancer cells could then be bound to them. The nanoparticles thus formed measure 100nm in diameter.
The materials encasing the gold centered nanoparticles possess special optical properties. A one ten-millionth of the incoming light beamed on the specialized material ricochets in a discrete wavelength pattern particular to the material used. The gold centers have been battered to magnify the ‘Raman effect’, allowing multiple materials to be viewed simultaneously by a Raman microscope.
The first group of mice were administered the dose rectally. A series of measurements at five times from five minutes up to two weeks were determined. The blood pressure, electrocardiograms and white-blood-cell count were monitored. Multiple tissues were tested for increased antioxidant enzymes or inflammatory proteins, indicating physiological pressure on the cells. The tissues were tagged with dyes to track dying cells.
Electron microscopy was used to examine the tissues and cells at regular intervals, all of which showed no signs of toxicity and found the gold remained attached to the organ colon and nowhere else. The nanoparticles werethen removed from the mice. Even when the nanoparticles were administered intravenously to the second group of 60 mice, no signs of toxicity were found. Laboratory tests conducted by attaching the nanoparticles to a peptide sensitive to tumor cells revealed no toxic effects.
Source: http://med.stanford.edu