Injectable, High Specific Surface Area Cryogel Microscaffolds Integrated with Osteoinductive Bioceramic Fibers for Enhanced Bone Regeneration

Abstract

Organic−inorganic composites with high specific surface area and osteoinductivity provide a suitable microenvironment for cell ingrowth and effective ossification, which could greatly promote bone regeneration. Here, we report gelatin methacryloyl (GelMA) cryogel microspheres that are reinforced with hydroxyapatite (HA) nanowires and calcium silicate (CS) nanofibers to achieve the goal. The prepared composite cryogel microspheres with open porous structure and rough surface greatly facilitate cell anchoring, simultaneously exhibiting excellent injectability. Compared to the only HA-or CS-containing counterparts, the GelMA cryogel microspheres composited with HA:CS (termed as GMHC) achieve sustained release of bioactive Ca, P, and Si elements, which are conducive to osteogenic differentiation of bone marrow mesenchymal stromal cells (BMSCs). These composite microspheres can prevent from forming peralkalic conditions, which is beneficial for cell growth. After injection of cryogel microspheres into rat calvarial defects, neo-bone tissue grows into their pores, showing tight integration. The embedded bioceramic components significantly promote bone regeneration, with the GMHC achieving the best regenerative outcomes. Promisingly, porous organic−inorganic composite cryogel microspheres, with high specific surface area, biodegradability, and osteoinductivity, can act as injectable microscaffolds to repair bone defects with enhanced efficiency, which may widen the scaffold strategy for bone tissue engineering.

Injectable Nano‐Micro Composites with Anti‐bacterial and Osteogenic Capabilities for Minimally Invasive Treatment of Osteomyelitis

“…The composite microspheres had a uniform size, stable morphology, and excellent mono‐dispersibility, indicating their superior injectability. [ 48 , 49 ] In addition, the injectability of the CaP@MS‐Oligo‐Van was verified through extrusion experiments (Video S1 , Supporting Information).…”

“…The incorporation of CaP nanosheets and Van did not compromise the structure and morphology of the hydrogel microspheres, maintaining their excellent injectability. [ 49 ] Energy dispersive X‐ray spectroscopy (EDS) analysis further demonstrated the presence of the corresponding Ca, P, and Cl elements in the CaP@MS‐Oligo‐Van samples (Figure 1d ). Herein, Ca and P were specific to CaP nanosheets and Cl was specific to Van.…”

Regulation of metabolic microenvironment with a nanocomposite hydrogel for improved bone fracture healing

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Organic–inorganic composite hydrogels: compositions, properties, and applications in regenerative medicine

“…Organic–inorganic composite hydrogels possess a compositional structure that closely resembles that of real bone, hence demonstrating favorable attributes such as biocompatibility, biodegradability, and osteoconductive characteristics. 227…”