Other Nanoparticles: general discussion

Abstract

Sara Carreira opened the discussion of the paper by Nicolas Barry: Why are your RuMs and OsMs so specic to cancer cells without using any targeting moiety?Nicolas Barry replied: We believe that the specicity comes from the size of the particles -passive targeting. Clinically-validated therapeutic and imaging NPs usually target cancer cells in a passive way. This is achieved by taking advantage of the enhanced permeability and retention (EPR) effect in tumor tissues. Tumor vasculature is highly disorganised, compared to the vasculature in normal tissues, and the vascular endothelium in tumors proliferates rapidly and discontinuously. This results in a higher number of fenestrations and open junctions (from 200 nm to 1.2 mm) than in normal vessels. Particles with a typical size of a few nanometres can therefore passively cross the tumor endothelial barrier through fenestrations, and accumulate at particular sites through blood hemodynamic forces and diffusion mechanisms.One of our objectives is to increase the size of our particles from 15 nm to a few hundred nanometres, in order to maximize this passive targeting. We also wish to introduce an active targeting moiety (e.g. specic peptides, antibodies) on the corona of the particles to increase this selectivity.Peter Dobson asked: Have you looked to see if any of your compounds are luminescent?Nicolas Barry responded: There are numerous examples of ruthenium compounds that are luminescent. Usually, arene Ru(II) complexes are not luminescent owing to the arene-metal interactions. Nonetheless, it is possible to introduce a luminescent ligand (such as a pyrene derivative) by functionalizing the 16-electron complexes (to make an 18-electron complex).This journal is