Innovative nanobubble treatment finds and destroys cancer cells in mice

Innovative technology developed by NIH-funded researchers has been able to find and facilitate the killing of cancer cells in mice without harming the nearby healthy tissue. A treatment using this technology in humans could reduce the rate of cancer recurrence or metastasis.

Cancer cells that cannot be removed by surgeons often cause tumors to return or metastasize. In a study published in Nature Nanotechnology in February, Dmitri Lapotko, Ph.D., and his team at Rice University (currently with Masimo Corporation, CA) describe a new way to combat these leftover cancer cells. In this new approach, tiny gold particles have cancer-specific antibodies attached to their surface, which enable the particles to be engulfed in high concentrations and cluster only in cancer cells. These gold clusters, when exposed to a short broad laser pulse, heat and evaporate surrounding liquid, producing a "plasmonic nanobubble." This nanobubble produces an "acoustic pop" which reveals the cancer cell and then causes an explosion that destroys it from the inside out.

Researchers have examined gold nanoparticles for treating cancer in the past, but the particles lacked specificity; they were unable to differentiate between healthy cells and cancer cells. Lapotko and his team are combatting this problem by combining the use of antibody-coated gold particles with the generation of nanobubbles created with a short laser pulse.

Gold particles can be injected prior to a surgery so they can travel to and cluster in cancer cells. After a tumor is removed in surgery, the laser (near-infrared) pulse is low energy, which can travel safely through a centimeter of tissue, is applied. The laser pulse only causes the nanobubble-induced damage in the remaining cancer cells with gold particles and are the only ones destroyed. This unique approach might be able to reduce the amount of unintended damage done to the patient, especially if the tumor is located in a sensitive area such as the brain, head and neck, breast, or prostate.

"This is a creative and novel approach that combines an understanding of the basic biophysics of heat transfer with the exquisite specificity and chemistry of the targeting antibodies," said Rosemarie Hunziker, Director of the program for Tissue Engineering at NIBIB. "It could become a powerful tool in our arsenal to fight cancer."

When surgeons injected these gold particles into mice with cancer before surgery, the initial results were impressive. While 80% of the mice in the operated group that did not receive the gold particle treatment died due to tumors that recurred within 10 days after surgery, none of the mice that received the additional nanobubble treatment regrew tumors in the following two months.

The researchers hope to begin clinical trials in humans in the next few years.