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Nanoparticle Size Tuning via Flow Chemistry: Small IONPs for Enhanced MRI Contrast

17 May 2021

Nanoparticle Size Tuning via Flow Chemistry: Small IONPs for Enhanced MRI Contrast

A collaboration among UCL Chemical Engineering’s Maximilian Besenhard, Luca Panariello and Asterios Gavriilidis, UCL’s Biophysics group and the IPCMS University of Strasbourg led to a novel flow synthesis of iron oxide nanoparticles (IONPs), practically unfeasible in batch reactors. A combination of fast mixing and precisely timed reagent addition stopping particles from growing, made it possible to synthesise small (≤5 nm) and colloidally stable particles. The particles’ high-surface to volume ratio makes them a promising material for T1 MRI contrast enhancement with longitudinal relaxivities (r1) higher than 10 mM−1 s−1. Such values have never been achieved with scalable and green water-based synthesis. This novel flow chemistry approach described in a Nanoscale publication brings one step closer the utilisation of IONPs as MRI contrast agents, that can be used as a replacement of current Gd complexes.

The flow chemistry approach was the key to success, as it allowed not only to determine the reaction kinetics, but also to fine tune the synthetic procedure of such rapidly forming particles. The sub-second precision for reagent addition and fast mixing times required would have been impossible to achieve via scalable batch procedures. This study demonstrates how flow chemistry facilitates new ways to tune nanomaterials and provides additional control handles, even for methods with rapid particle formation.