Bioactive glass functionalized chondroitin sulfate hydrogel with proangiogenic properties

Abstract

Blood vessels play an important role in bone defect repair and growth, and a critical challenge of bone defect repair is the promotion of blood vessel formation. Most of the current methods promote vascularization by adding specific growth factors, which are costly and easy to inactivate. In this study, we developed a covalently cross‐linked aminated bioactive glass nanoparticle‐chondroitin sulfate methacrylate (ABGN‐CSMA) organic‐inorganic composite hydrogel with angiogenic properties. The amino groups of the ABGNs form covalent bonds with the carboxyl groups on CSMA. Surface amination modification of BGNs not only improved the dispersion of BGNs in CSMA but also significantly improved the mechanical properties of the composite hydrogel. The largest storage modulus (1200 Pa), the largest loss modulus (560 Pa) and the strongest resistance to deformation of the hydrogel are seen at 10% concentration of ABGNs. Simultaneously, the local pH stability and sustained ion release of the composite hydrogel are conducive to cell adhesion, proliferation, and angiogenesis. This work provides evidence for the development of covalently cross‐linked organic‐inorganic composite hydrogels with angiogenic properties.

Hybrid gelatin/oxidized chondroitin sulfate hydrogels incorporating bioactive glass nanoparticles with enhanced mechanical properties, mineralization, and osteogenic differentiation

“…The alkalinity of the medium should be greater with the concentration of MBGNs incorporated increasing, which could thus promote the Schiff's base reaction and accelerate the gelation. Also, the surface of MBGNs could be hydrated to form silanol groups (Si–OH) in an aqueous medium that could interact with the amino groups and carboxyl groups on Gel-OCS to form hydrogen bonding, which could also actively promote the crosslinking [ 19 , 34 ]. Additionally, the released Ca 2+ might commence ionic gelation of OCS [ 35 ].…”

“…Freeze-dried polymeric hydrogels can naturally swell when they contact with an aqueous solution and exhibit relatively low stiffness, which may enlarge the pore sizes and allow for cell migration when they are applied in vitro and in vivo studies [ 39 ]. Also, the Gel-OCS hydrogel could degrade in an aqueous environment, thus leading to larger pores and voids over the incubation [ 19 , 40 ]. Therefore, hydrogel-based scaffolds with relatively small pore sizes (<100 μm) should also be sufficient for cell migration [ 41 ].…”

“…In all spectra, the characteristics bands of Gel and OCS could be observed. All the hydrogel demonstrated the characteristic bands reflecting its OCS structure, e.g., 947 cm −1 (C–O stretching), 1122 cm −1 (C–C stretching), and a shoulder starting at 1045 cm −1 (C–C and C–O stretching) [ 19 ]. The band located at 1532 cm −1 could be assigned to the N–H stretching vibration of amide II while the band located at 1633 cm −1 could be assigned to C–O and C–N stretching vibration of amide I in gelatin [ 34 ].…”

“…However, after the incorporation of MBGNs, the mineralization of the hydrogels was promoted through the ion exchange and dissolution of MBGNs [ 13 ]. Bioactive glass nanoparticles have been used as bioactive fillers to enhance the mineralization of chondroitin sulfate [ 19 ] hydrogels and gelatin coatings [ 56 ]. Similar to the findings in the current study, the presence of BGNs significantly enhanced the formation of HA as well as promoting mechanical properties.…”

“…OCS was synthesized using a method reported previously [ 19 ]. Briefly, 1.25 g of CS was dissolved in 20 mL of distilled water and stirred at 4 °C.…”