Given that a GNP has been shown to quench fluorophores in close proximity by up to 99.97%, it is safe to assume that the observed QE represents the fraction of the added lectins that have bound to Gx-DiMan. Previously, we measured the QEs for 1:1 mixed lectin + G5-glycan samples at varied concentrations, and then fitted the QE -concentration relationships by the Hill equation to derive their apparent Kds. While this worked well for the small G5-glycans (due to relatively low its ), it did not work for the large G13-and G27-glycans, owing to their much stronger inner filter effect (e.g.,  for G13 and G27 being ~21 and ~220 fold that of G5, respectively). Interestingly, we found that the QE stayed almost constant for a fixed amount of Gx-DiMan after mixing with DC-SIGN over a certain lectin: Gx molar ratio, although the QE was found to decrease as the lectin: Gx molar ratio was further increased, possibly due to surface saturation (see SI, Fig. ).