Title : Targeted nanoparticles for diagnostic and theranostic applications
Targeted nanoparticles provide an exciting opportunity for delivery of drugs to specific tissue locations but also for imaging and sensing applications. Many drugs, and in particular chemotherapy agents, are too toxic to deliver systemically, but when packaged into nanoparticles and directed to a specific target off-target effects are avoided and a much higher doses are delivered. The same nanoparticles can carry fluors and other imaging agents and in some cases can act both to image solid tumours and also to deliver therapy. Work will be described using antibodies and synthetic binding proteins, Affimers against the biomarker protein CEA1 to target nanoparticles to colorectal cancer cells, both in 2D culture and as 3D spheroids and in mouse models in which SCID mice bear LS174T colorectal cell line xenografts. Targeting of silica nanoparticles, loaded with hydrophilic fluors and photosensitizers (PS) for imaging and or photodynamic therapy respectively will be described and the therapeutic effects of PS-nanoparticles shown. For hydrophobic chemotherapy agents, non-bilayer forming lipidic nanoparticles (“cubosomes“) loaded with hydrophobic organo-copper cytotoxins results in specific and efficient imaging and cell killing of cancer cells and reduction of xenografted colorectal cancer cells. Finally, the immobilisation chemistries involved to tag the bioreceptor (targeting agent) to the nanoparticle surface and effect correct, specific targeting will be discussed.