Tumour tissue in the lung contains high concentrations of certain proteases, which are enzymes that break down and cut specific proteins. The scientists took advantage of this by modifying the nanocarriers with a protective layer that only these proteases can break down, a process that then releases the drug. Protease concentrations in the healthy lung tissue are too low to cleave this protective layer and so the medicines stay protected in the nanocarrier.

"Using these nanocarriers we can very selectively release a drug such as a chemotherapeutic agent specifically at the lung tumour," reports research group leader Meiners. "We observed that the drug's effectiveness in the tumour tissue was 10 to 25 times greater compared to when the drugs were used on their own. At the same time, this approach also makes it possible to decrease the total dose of medicines and consequently to reduce undesirable effects."

Further studies will now be directed to examine the safety of the nanocarriers in vivo and verify the clinical efficacy in an advanced lung tumour mouse model.

van Rijt, S. et al. (2015): Protease Mediated Release of Chemotherapeutics From Mesoporous Silica Nanoparticles to Ex Vivo Human and Mouse Lung Tumors, ACS Nano. doi: 10.1021/nn5070343