The biotin functionalised spin labelled nanoparticles could be simulated using the data shown in   Figure S16a ) . The nanoparticles with avidin - peroxidase could roughly be fitted with a particularly broad component with a rotational correlation time of 10 ^ -8.0 s , indicating that the label was in a hindered motion environment ( Figure S16b ) . However , due to the significant broadening , it was difficult to obtain an exact fit , as the smaller peaks are lost in the noise . In contrast to the Con A binding , there was a significant broadening of the peaks , most likely due to the tight binding of the avidin - peroxidase leading to significantly reduced molecular motion . Using these two components , it is possible to create a simulated titration , to demonstrate how the line shape would be influenced by an increasing population of the protein - label complex ( Figure S17 ) . When the simulations were not normalised , we observed that the line heights were significantly smaller than those of the free spin label . It is likely that it would be difficult to detect the changes in the line height for   To further rule out viscosity as a source of the binding profile observed in Figure S7 , a viscosity study was conducted with 100 µM spin labelled mannose 4 with varying amounts of glycerol , the viscosity of the solution increases , there is a reduction in tumbling rates of the nitroxide spin label , and a broadening of the resonances . As before , the ratio between the high field and central field resonance heights may be plotted against the % glycerol to give a binding profile ( Figure S18 ) . Figure S18 : The change in relative line height between the high field and mid field resonances against % glycerol for 100 µM solutions of the nitroxide radical 4 in 0.01 M potassium borate buffer with various amounts of glycerol .