Recent experimental efforts have investigated nanoparticle solution as glues for hydrogels, focusing on the role of nanoparticle size and shape in influencing adhesion. Here, we use molecular dynamics simulations together with a coarse-grained model and consider a variety of different nanoparticle morphologies to expand on these experiments. Our main result is to show that while nanoparticles’ shape and size can play an important role, whether and how much these two factors affect adhesion strongly depend on the amount of nanoparticles loaded at the interface, as well as on the mutual interaction between the nanoparticles. Furthermore, we suggest that the nanoparticle gluing performance can be qualitatively understood in terms of the relationship between the shape and surface curvature, with lower curvature shapes providing, for different reasons, stronger adhesion in a wider range of nanoparticle loading.