Core-shell silica and fluorogenic hyaluronan nanomaterials in magnesium hydroxyapatite scaffolds for bone regeneration.

Nanomaterials represents a class of multifunctional materials that can play a key role in multiple applications of biomedicine. In case of severe bone defects due to trauma, cancer or aging, a huge demand for more effective treatments is one of the important challenges in clinical practice. Biomaterials for bone tissue engineering (BTE) is one of the appealing approach to enhance regenerative capability by combining several biocomponents like biomimetic materials and nanomaterials, cells, growth factors. Hydroxyapatite (HA) represents the most used based biomaterial for bone regeneration. However, there is still a crucial demand for new HA-based biomaterials satisfying clinical needs in terms of improved osteointegration and osteoregeneration. Here we show the synergic application of two nanomaterials, i.e., a fluorogenic hyaluronan nanogel (hyaluronic acid with Rhodamine B, HyRB) and a class of theranostic core–shell silica nanoparticles (PluSNPs) integrated into MgHA-type I collagen-based scaffolds. This novel biomaterial (HyRB/PluSNPs doped MgHA) showed improved performance in osteoregeneration, both for osteoconductivity and osteoinductivity; furthermore, the HyRB/PluSNPs nanomaterials can act as contrast agent for fluorescence imaging and have a potential for targeted drug delivery and for phototherapy. Results pave the way for the development of new multifunctional biomaterials combining the advantages of improved osteoconductivity/osteoinductivity of HyRB/PluSNPs with their potential drug delivery functionality and phototherapeutic properties.