Nanoparticles alone form 'wave of destruction' against cancer cells


Cornell Professor Ulrich Wiesner’s C-dots are showing more and more that they could be the next big step in nanotech drug delivery. In their latest incarnation, the diagnostic and delivery combination particles have shown that they can alone deprive cancer cells of nutrients, resulting in their death.

C-dots were developed as a small--even by nano standards--diagnostic tool that can pass safely through a patient's urine rather than breaking down in the liver. Normally, drilling a small hole in the C-dots allowed these tiny particles to hold drugs, not to mention the fluorescence designed as a diagnostic for cancer.

And now the particles show intrinsic properties that fight cancer. In large doses, the nanoparticles have triggered cell death in cancer cells called ferroptosis, which is a recently recognized form of regulated cell death that comes from smaller-than-normal mitochondria.

“If you had to design a nanoparticle for killing cancer, this would be exactly the way you would do it,” Wiesner said. “The particle is well tolerated in normally healthy tissue, but as soon as you have a tumor, and under very specific conditions, these particles become killers.”

The C-dots absorb iron from the environment and deliver it to cancer cells because of their peptide coating, a process that ruptures plasma membranes in the cancer cells. Within 24 to 48 hours, a “wave of destruction” wreaked havoc among the cells in culture and shrank tumors in mice who had high doses of the injection.

“We’ve found another tool that people have not thought about at all so far,” Memorial Sloan Kettering Cancer Center’s Michelle Bradbury said. “This has changed our way of thinking about nanoparticles and what they could potentially do.”