Biocompatible nanocomposite scaffolds based on carrageenan incorporating hydroxyapatite and hesperidin loaded nanoparticles for bone tissue regeneration

Abstract

In this study, injectable and osteoinductive carrageenan (CGN)‐based composite hydrogel integrated with 1% wt/vol hydroxyapatite (HA) and hesperidin (HPN) loaded poly (3‐hydroxybutyrate‐co‐3‐hydroxyvalerate acid) nanoparticles (PHBV NPs) were developed as a scaffold for bone tissue engineering. Accordingly, HPN was encapsulated into PHBV NPs by the oil in water emulsion‐solvent evaporation technique and optimized using the fractional factorial design. Then, the effects of the amount of drug, polymer, surfactant concentration, sonication time, and the water/organic phase volume ratio on the characteristics of NPs, including particle size (PS), polydispersity index (PdI), zeta potential (ZP), drug loading (DL) % and encapsulation efficiency (EE) % were investigated. The crystalline state of HPN and the interaction between the drug and the polymer were also investigated using the x‐ray powder diffraction method and the Fourier transform infrared method, respectively. Further, CGN hydrogel was developed and loaded with optimized NPs and HA (HPN‐PHBV NPs‐CGN/HA hydrogel). The prepared hydrogel was then characterized for drug release, swelling and degradation behavior, mechanical properties, and injectability. In addition, the potential of the composite hydrogel as bone tissue scaffolds was assessed by the MTT assay, alkaline phosphatase (ALP) activity, and alizarin red S staining. The optimized formulation had the size of 353.5 nm, PdI of 0.43, EE% of 88.47%, DL% of 29.58% and the ZP of −17.4. HPN‐PHBV NPs‐CGN/HA hydrogel also showed sustained drug release, as compared to the HPN‐CGN/HA hydrogel. Further, the hydrogel containing HA showed improved mechanical properties, as compared with the HA free one. In addition, HPN‐PHBV NPs‐CGN/HA hydrogel significantly enhanced MG63 cell proliferation, ALP activity and matrix mineralization, as compared with other groups. Overall, the use of this hydrogel with enhanced osteogenic capacity could be considered as an effective approach for bone tissue engineering.