The osteogenic effects of sponges synthesized with biomaterials and nano-hydroxyapatite.

Artificial bone substitutes have been developed using various biomaterials for use in medicine. Silk fibroin (SF) displays excellent mechanical properties and cell compatibility. Nonetheless, the mechanical properties of silk fibroin scaffolds used in artificial bone substitutes are weaker than those of natural bone, and silk fibroin is deficient as an osteogenic agent. This limits their effectiveness in bone tissue engineering. We added nano-hydroxyapatite (nHAp) particles to an existing cell-based artificial bone substitute with a silk fibroin scaffold, which will improve its mechanical properties and osteogenic efficacy, leading to significant bone regeneration. The mechanical characters of silk fibroin modifying with nHAp were measured by Atomic Force Microscopy Analysis, dispersive x-ray spectroscopy, Porosity measurement, and Microcomputed Tomography. The proliferation and toxicity of a fibroin/dextran/collagen sponge (FDS) containing nHAp were evaluatedin vitro, and its osteogenic efficacy was evaluated using nude mouse and rabbit radius defect models. The defect area was repaired and showed callus formation of new bone in the rabbit radius defect models of the nHAp-FDS-treated group, whereas the defect area was unchanged in the FDS-treated group. The nHAp-FDS manufactured in this study showed significant bone regeneration owing to the synergistic effects of the components, such as those due to the broad range of pore sizes in the sponge and protein adsorbability of the nHAp, which could be suggested as a better supportive material for bone tissue engineering.

Injectable Click Fibroin Bioadhesive Derived from Spider Silk for Accelerating Wound Closure and Healing Bone Fracture.

Wound closure is a critical step in postoperative wound recovery. Substantial advancements have been made in many different means of facilitating wound closure, including the use of tissue adhesives. Compared to conventional methods, such as suturing, tissue bioadhesives better accelerate wound closure. However, several existing tissue adhesives suffer from cytotoxicity, inadequate tissue adhesive strength, and high costs. In this study, a series of bioadhesives was produced using non-swellable spider silk-derived silk fibroin protein and an outer layer of swellable polyethylene glycol and tannic acid. The gelation time of the spider silk-derived silk fibroin protein bioadhesive is less than three minutes and thus can be used during rapid surgical wound closure. By adding polyethylene glycol (PEG) 2000 and tannic acid as co-crosslinking agents to the N-Hydroxysuccinimide (NHS), and 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) reaction, the adhesive strength of the bioadhesive became 2.5 times greater than that of conventional fibrin glue adhesives. Silk fibroin bioadhesives do not show significant cytotoxicity in vitro compared with other bioadhesives. In conclusion, silk fibroin bioadhesive is promising as a new medical tool for more effective and efficient surgical wound closure, particularly in bone fractures.