Researchers at North Carolina State University and the University of North Carolina at Chapel Hill have developed a new drug delivery technique that uses a biodegradable liquid metal to target cancer cells. The liquid metal drug delivery method promises to boost the effect of cancer drugs. To date, the technique has only been tested in an animal model.

The advance here is that we have a drug-delivery technique that may enhance the effectiveness of the drugs being delivered, can help doctors locate tumors, can be produced in bulk, and appears to be wholly biodegradable with very low toxicity.

To create the nano-terminators, researchers place the bulk liquid metal (gallium indium alloy) into a solution that contains two types of molecules called polymeric ligands. The solution is then hit with ultrasound, which forces the liquid metal to burst into nanoscale droplets approximately 100 nanometers in diameter. The ligands in the solution attach to the surface of the droplets as they break away from the bulk liquid metal. Meanwhile, an oxidized “skin” forms on the surface of the nanodroplets. The oxidized skin, together with the ligands, prevents the nanodroplets from fusing back together.

The anticancer drug doxorubicin (Dox) is then introduced into the solution. One of the ligands on the nanodroplet sucks up the Dox and holds on to it. These drug-laden nanodroplets can then be separated from the solution and introduced into the bloodstream. The second type of ligand on the nanodroplets effectively seeks out cancer cells, causing receptors on the surface of the cancer cell to latch on to the nanodroplets. The cancer cell then absorbs the nanodroplets.

Once absorbed, the higher level of acidity inside the cancer cell dissolves the oxidized skin of the nanodroplets. This releases the ligands, which will go on to release the Dox inside the cell. “Without the oxidized skin and ligands, the nanodroplets fuse together, forming larger drops of liquid metal