Injectable bionanocomposite hybrid scaffolds with responsive control for enhanced osteochondral tissue regeneration

Restoration of articular hyaline cartilage within osteochondral tissue defects has been a principal target in the field of tissue engineering due to poor functional regeneration of this avascular and heterogeneous tissue following current treatment options. The major focus thus far has been in constructing implantable scaffolds, which can be readily designed to offer appropriate mechanical properties. However, the use of implantable scaffolds requires open surgery and often cannot be readily applied to defects of irregular shape. Thus, it has become of high interest to develop minimally invasive and degradable hydrogel-based materials capable of delivering and maintaining encapsulated cells in a non-toxic manner and encouraging functional tissue regeneration. This paper reports on the synthesis and characterization of a novel class of injectable, thermally and chemically dual-gelling bionanocomposite hydrogels from thermogelling macromers (TGMs) based on poly(N-isopropylacrylamide) (pNiPAAm), degradable polyamidoamine (PAMAMs) crosslinking macromers, and functional hybrid inorganic iron oxide (Fe₃O₄) nanoparticles capable of responding to an external magnetic field to stimulate cell activity and control the regenerative process in situ in a spatiotemporal manner.