Cancer imaging, targeting and therapy can be delivered using mesoporous silica nanoparticles (MSNs) claim scientists in Taiwan. 

The best use of nanoparticles in cancer therapy so far combines diagnostic contrast agent with an anticancer drug. But as they are not targeted, large doses are often needed which results in tissue loading with potentially large levels of cytotoxic agents, causing unwanted side-effects in patients. 

Therefore tri-functionalisation of nanoplatforms that also include a biomolecular ligand for high targeted delivery is the next step for nanoparticle-based cancer therapy. Of particular interest are MSNs which have large surface area and pore volumes as wells as having a unique structure that contains three distinct domains that can be independently functionalised. 

With this in mind, Leu-Wei Lo at the National Health Research Institute and his team sequentially introduced different groups into the different domains on MSNs to optimise their therapeutic efficiency. A new fluorescent dye (ATTO647N) was added directly into the MSN's silica framework for traceable imaging. Nanochannels in the second domain were functionalised with an oxygen-sensing, porphyrin-based photosensitizer, for photodynamic therapy. Finally, they used a peptide that is over-expressed in some tumour cells conjugated to the outermost surface of the MSN particle to act as the cell-targeting group. 'Many people have been using these MSNs for some studies, but I think this work is the first one to represent the first use of all the topologically distinct domains,' explained Lo. 

In vitro evaluation of the tri-functionalised MSNs shows that they possess excellent targeting specifity, minimal collateral damage and a high therapeutic effect, says Lo. The group demonstrate that there is a dramatic difference in the post-irradiation cytotoxic response of U87-MG cancer cells treated with the MSN, with only 10 per cent surviving treatment, compared to results using an untargeted control. 

Dr Bouzid Menaa, an expert in bionantechnology and drug nanocarriers at Fluorotronics, Inc., San Diego, US says 'the work is very interesting and important to the field of cancer treatment. In general nanoparticles that are functionalised individually can be used as a drug delivery system; these 3-in-1 functionalised nanomaterials are really new. The results are very impressive and open up the door to many wide applications.' 

The team is now focusing on using the MSNs in vivo and is investigating ways to improve the excretion of nanoparticles from the body. 

Anna Watson 

Enjoy this story? Spread the word using the 'tools' menu on the left or add a comment to the Chemistry World blog.