A new diagnostic technique approved for a human clinical trial targets cancer cells themselves with tiny tracers that atomically bond to rogue cells wherever they appear in the body.
The study, which will take place at Memorial Sloan-Kettering Cancer Center in New York, is intended to test if the 'sticky dots' work as well in humans as they did in mice and pigs.
"It's like flypaper," says Louis Marzella, deputy director of medical imaging products at the US Food and Drug Adminstration. "It will stick to the item of interest."
For this clinical trial, scheduled to start in a few weeks, doctors are recruiting five terminally ill melanoma patients who will be injected with tiny silica spheres - each less than 8 nanometres in diameter - that enclose several molecules of dye.
The dots will be coated with polyethylene glycol, which the body won't recognise as a foreign substance, labelled with radioactive iodine to make them visible in scans and sprinkled with organic molecules that bind to tumour cells.
Dots that don't find cancer cells to latch on to are designed to pass through the kidneys and out of the body in urine. Those that find a target cell will fluoresce when exposed to near-infrared light, revealing the location and spread of cancer.
"We want to find out what happens when particles are injected into humans, are they as benign as they were when they were injected into animals?" says Cornell University materials scientist and engineer Ulrich Wiesner.
"We want to know a lot about the safety of these products," added Marzella.
Revolutionising cancer surgery
If successful, the nanoparticles will not only present doctors with a powerful new imaging tool, they also could deliver medications to kill cancer cells on contact, with far fewer side effects than conventional treatments.
"That's the next level of complexity," says Wiesner. "It's clearly something we want to do."
Eventually, cancer sticky dots, which can be illuminated by small optical devices, could revolutionise cancer surgeries by illuminating exactly where a doctor needs to cut.
"The only thing that currently guides surgeons is his or her experience," says Wiesner. "We want to provide an engineering parameter. This may really change things."