This in turns led to the successful implementation of an efficient antibiotic treatment and tooth whitening under exposure to green light. In the field of damaged tissue treatment, attention has focused on hybrid hydrogels endowed with specific mechanical and/or biochemical attributes. For example, by modulating substrate stiffness through the incorporation of iron oxide NPs, GelMA hydrogels can be adapted to effectively repair knee joint cartilage defects through enhancement of chondrocyte metabolic activity. Compared with GelMA controls, these hybrid hydrogels demonstrated the ability to recruit at the site of injury greater number of cells, including peripheral chondrocytes, as early as one week after surgery. By the sixth week, proteoglycan accumulation and the presence of osteoid components in the newly regenerated tissue had increased markedly. Similar mechanical reinforcement of hydrogels composed of bioactive and osteoconductive polymers (e.g., Gel, HA, PGA, ALG) was also achieved through the incorporation of mineral NPs such as (i) HAP and WTK and (ii) silicates (e.g., Lap, Mmt ). These inorganic NPs exhibit osteogenic properties and biomineralization capabilities, making the resulting materials highly appealing for applications in bone regeneration with a synergistic action of all components. Such formulated hybrid hydrogels have been used for the treatment of different skeleton lesions. Successful examples included defects in load-bearing long bones (e.g., femur, tibia), where the material must additionally withstand the specific physiological demand of these regions; nasal sinus osteotomy and cranial lesions in murine or rabbit models (up to 1cm in size). Alongside the compositions, the formulation strategies also had a significant impact on the therapeutic outcomes. For instance, the loading of HAP in PCL NPs and their incorporation in the core of a biphasic core/shell Gel scaffold proved to be the most effective compared to their incorporation in the shell. After freeze drying, the first configuration resulted in the formation of a highly porous interconnected network, whose microstructure facilitated cell infiltration for new bone formation, leading to improved healing performance (Figure ). Adapted with permission. Copyright 2021 The Royal Society of Chemistry.