“…Controlling the spatial distribution of nanoparticles, both with respect to their placement as isolated particles or particle agglomerates of different sizes in a three dimensional framework and then placement of this framework in the infected tissue environment, is relevant, as an optimal arrangement can significantly increase the proton relaxivity value in two possible ways: (a) by generating very high magnetic field gradients from the collective magnetic behaviour of individual nanoparticles in the framework 14,15 and (b) by optimally trapping the water protons within the three dimensional framework, such that a significant increase in the interaction between the water protons and the superparamagnetic nanoparticles along with a reasonable proton exchange rate is achieved. 16,17 One possible way by which the "spatial distribution" factor can be employed is by using a bio-compatible, hydrophilic and flexible substrate, such as graphene oxide 18 as the framework material on which superparamagnetic nanoparticles can be organized in a controlled manner.…”