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02 December 2016

Student explores tracking drugs around body

Riya Radia, a former student of the Department of Chemistry at King’s College London, has recently published the work she carried out during her final year research project, under the supervision of Dr Rafael T. M. de Rosales in the journal ACS Nano. Titled “Exploiting the Metal-Chelating Properties of the Drug Cargo for In Vivo Positron Emission Tomography Imaging of Liposomal Nanomedicines”, the paper explores the use of positron emission tomography imaging (PET) to see where certain cancer drugs accumulate in the mice with a view to eventually developing better treatments for people.

Blue molecule model
Blue molecule model

Everybody is unique and drugs will accumulate in different concentrations depending on the type of cancer and the person. This research looked into radiolabelling and tracking preformed nanomedicines via PET – a whole-body functional imaging technique that is used to observe biomolecules and metabolic processes in the body.

Some anti-cancer drugs are delivered to cancerous tissues via liposomes, which are tiny bubbles made of material that is structurally similar to cell membranes. The blood vessels of tumours are more leaky than those of healthy tissues, so liposomes can fit between them more easily. Most of the time this is successful, but occasionally the liposomes are directed elsewhere and end up in healthy tissue instead. Also, a large number of anti-cancer drugs bind readily to metal ions such as copper, manganese and zirconium. These metal ions all have radioactive isotopes that release a particle called a positron as part of their decay. These positrons can be tracked using PET and therefore can track the liposomes carrying the anti-cancer drugs. This can provide us with the information to determine where the drugs are travelling throughout the body. The paper worked on a mouse-model of metastatic breast cancer and found that most of the time the liposomes were travelling to tumours and metastases in high amounts, but some did end up in organs that were free of cancer cells.

This research may be the beginning of image guided delivery of drugs to targeted areas in current and future nanomedicine clinical studies.