When silica nanoparticles (SiNP) are stored in aqueous solution, even for few hours, they have a tendency to form agglomerates and therefore adapt inhomogeneous structures. We have previously reported on a very practical method to store SiNP in responsive hydrogel, which significantly improves the colloidal stability of the SiNP upon storage. In this work, we present data that support the applicability of our gel-storing concept in a model in vitro and exovo systems. We have confirmed that SiNP kept in the responsive hydrogel do not undergo through undesirable morphological changes and while in storage they maintain their excellent colloidal stability. The effect of SiNP hollowing (i.e. dissolution of the core of the particles that leaves empty cavity inside) was significantly inhibited in the hydrogel, which is critical feature for any nano-medical applications (e.g. controlled drug release). Importantly, to demonstrate the applicability of the hydrogel-storing concept within a biologically relevant context, we have evaluated the cytotoxicological effects of the responsive SiNP-gel formulation in a model in vitro (human cell line U87GM and hemocompatibility using sheep blood) and ex ovo (chick area vasulosa) experiments. The key results clearly show that there is no inherent toxicity from the particles or from the gel towards cells or live animals. All toxicological values were comparable within the control groups and no differences in toxicological response could be observed between the SiNP stored in hydrogel and the control nanoparticles stored in the solution.