On the other hand, some nano-objects can have a detrimental effect on the formation of the matrix network, by prolonging or even hindering the gelation process. This was shown with 0.9 wt% content of PS snowman-like janus NPs dispersed in a double-network hydrogel composed of CS and ALG, while samples containing 0.3 wt% showed a faster rate of gelation than the NP-free counterpart. In another example, when CNC-CHO were blended with a mixture of adipic acid dihydrazide-modified CMC and Dex-CHO, CNC aggregation and absence of gelation were observed when their concentration exceeded 2 wt%. Similarly no gelation occurred when more than 30% v/v of nanocapsules were incorporated into a fibrin/HA hydrogel intended for injection in the intraarticular (IA) cavity, and as little as 0.2 wt% of PDA NPs could be incorporated into a PDMAEMA-based matrix to ensure a gelation time compatible to intratumoral administration (around 450 s). Likewise, although the gelation of a Pluronic F-127 hydrogel containing PLA NPs took slightly longer than that of the pristine hydrogel, yet it did not compromise its applicability on wounds without leakage. Similarly, a higher temperature (from 29.4 to 35.7 °C) was required to induce gelation of a CS matrix after incorporation of Au-loaded porous silicon NPs, due to the formation of NP/CS hydrogen bonds. Nevertheless, the material retained its ability to gel under physiological conditions and could be used for intratumoral administration. In another example, the altered interaction of the polymer components, was responsible of the slower gelation rate of a PEG-based hydrogel in presence of PEDOT NPs. When looking at the inverse phase change, the electrostatic repulsion among negatively charged PDA-coated Au NPs interfered with the network of hydrogen bonds within a PNAAm matrix, leading the gel-sol transition to occurr at lower temperatures (55 vs 60 °C) compared to the bare hydrogel. In other examples, the incorporation of nano-objects conferred to the hydrogel additional properties for biomedical applications without affecting the gelation properties.