Like special-forces troops laser-tagging targets for a bomber pilot, tiny particles that home in on malignant brain tumors, such as glioblastoma, may someday enable neurosurgeons to remove these malignancies with unprecedented accuracy.
The prognosis for glioblastoma is bleak: the median survival time without treatment is three months. Surgical removal of such tumors — a virtual imperative whenever possible — prolongs the typical patient’s survival by less than a year. One big reason for this is that it is almost impossible for even the most skilled neurosurgeon to remove the entire tumor while sparing normal brain.
It's thought that microscopic remnants of the particularly rough-edged - and particularly nasty - brain tumors called glioblastomas may be largely responsible for this tumor's ultimate recalcitrance to surgical removal.
Gambhir and his teammates have engineered brain-tumor-seeking particles measuring less than five one-millionths of an inch in diameter - about one-sixtieth that of a human red blood cell. These particles' gold centers are coated with materials that, in the study, made it possible to do three things: (1) preoperatively locate a human glioblastoma tumor growing in a mouse's brain; (2) envision the tumor mass the as it's being excised; and (3) importantly, guide the scalpel immediately afterward in the removal of myriad minuscule tentacles that snake outward from these tumors' bulk to invade healthy surrounding tissue. Similarly, the nanoparticles highlighted isolated microscopic tumor-cell patches, called micrometastases, dotting otherwise healthy tissue. Normally, these would have been invisible to the surgeon's naked eye, and thus might have lived to recur another day.
Previously: Nanomedicine moves one step closer to reality