For instance, the ionization of CMC at pH 7.4, coupled with the electrostatic repulsion of negatively charged graphene QDs, led to an increase in water uptake as the pH transitioned from 1.2 to neutral values. Similarly, repulsion between CS chains and triethyleneglycoldecorated Au NPs, which are protonated at low pH values, promoted swelling. In both cases, the observed effect was found to correlate with the NP content.