Researchers from Technion Institute of Technology in Israel reported on a method of tagging cancer drugs with “barcodes” to monitor tumor growth. The team detailed their methods in a study published in the November issue of Nature Communications.

The nanoparticle drug delivery system are tagged with synthetic DNA, which act as barcodes used to track the tumor’s response to medication. The drugs are loaded into the nanoparticles, which travel through the circulatory system and stick to tumor cells.

To find out if a drug is working, researchers can perform a biopsy of the tumor and match the synthetic DNA to the compound.

So far, this has been tested on laboratory mice to compare a cancer drug against a placebo. The cancer drug successfully infiltrated and slowed the growth of a tumor while the placebo drug did not touch the tumor. The researchers identified the cancer drug within the tumor cells using the DNA “barcode” 2 days after the compound was delivered to the tumor.

The researchers point out that this technology isn’t limited to cancer medication and could be translated to other drugs for a variety of conditions. The work is another step in an effort to move towards more personalized treatment, especially when tumors develop resistance to chemotherapy after several treatments.