Nano-Hydroxyapatite Bone Substitute Functionalized with Bone Active Molecules for Enhanced Cranial Bone Regeneration

Abstract

The aim of this study was to synthesize and characterize a nano-hydroxyapatite (nHAP) and calcium sulfate bone substitute (NC) for cranioplasty. The NC was functionalized with low concentrations of bone morphogenetic protein-2 (BMP-2) and zoledronic acid (ZA) and characterized both in vitro and in vivo. In vitro studies included MTT, ALP assays, and fluorescent staining of Saos-2 (human osteoblasts) and MC3T3-E1 (murine preosteoblasts) cells cultured on NC. An in vivo study divided 20 male Wistar rats into four groups: control (defect only), NC, NC + ZA, and NC + ZA + rhBMP-2. The materials were implanted in an 8.5 mm critical size defect in the calvarium for 12 weeks. Micro-CT quantitative analysis was carried out in vivo at 8 weeks and ex vivo after 12 weeks. Mineralization was highest in the NC + ZA + rhBMP-2 group (13.0 ± 2.8 mm) compared to the NC + ZA group (9.0 ± 3.2 mm), NC group (6.4 ± 1.9 mm), and control group (3.4 ± 1.0 mm) after 12 weeks. Histological and spectroscopic analysis of the defect site provided a qualitative confirmation of neo-bone, which was in agreement with the micro-CT results. In conclusion, NC can be used as a carrier for bioactive molecules, and functionalization with rhBMP-2 and ZA in low doses enhances bone regeneration.

Nanostructured surface bioactive composite scaffold for filling of bone defects

“…These data indicate that the scaffold has good biocompatibility: human MSCs adhered to and proliferated on the surface of the scaffold, and their metabolic activity was normal. The similarity of the XRD TEM, and BET results of natural bone and collagen fibers mineralized with nanosized HA, [6][7][8][9][10][11][12][13][14][15][16][17][18] may explain the biomimetic effect in terms of osteointegration, cell seeding, and formation of new bone. However the hydrophobic PCL could hamper differentiation of MSCs.…”

“…Nano-hydroxyapatite (nHA), which is composed of the same ions as the major mineral constituent of bone, is an attractive implant material for bone regeneration due to its biocompatibility and osteoconductivity properties. Furthermore, it does not cause systemic toxicity or immunological reactions [13][14][15]. Porous HA scaffolds are used in bone-tissue engineering, as their architecture mimics very closely that of the bone extracellular matrix (bECM), thereby providing a favorable environment for biological processes [16][17].…”

From Dermal Patch to Implants—Applications of Biocomposites in Living Tissues

“…This surgery consists of repairing the bone defect using materials such as metals, ceramics, polymers and autologous bone grafts [31]. Focusing on finding alternatives to current bone grafts used in cranioplasty, Teotia et al [32] developed a hydroxyapatite bone substitute for enhanced cranial bone regeneration. The biocomposite cement was composed of nanohydroxyapatite, in order to mimic the nanotopography of bone, calcium sulfate, a based material used in bone fillers [33] and bioactive molecules (BMP and ZA), to provide osteoinductive properties and enhance bone formation.…”

“…Scaffolds were implanted in rats with cranial defects. Reprinted with permission from Reference [32].…”

“…Nanohydroxyapatite and glycol chitosan [10] Hydroxyapatite and polymeric blend (fibroin, chitosan and agarose) [11] Calcium silicate, zinc silicate and graphene oxide [15] Collagen, silk fibroin and dECM [26] Boron nitride and boron trioxide [28] Nanohydroxyapatite, calcium sulfate and bioactive molecules [32] Orthopedic Implants PEEK and graphene oxide [39] CFRPEEK, nanohydroxyapatite, carboxymethyl, chitosan and bone forming peptide [41] Polyphenylene sulfide and nanohydroxyapatite [42] Polyimide and tantalum pentaoxide [43] Hydroxyapatite, ceria nanoparticles and silver nanoparticles [44] Wound Healing Polycaprolactone and gelatin [54] Chitosan, polyethylene oxide and fibrinogen [57] Collagen, alginate and silver nanoparticles [60] Polyurethane, keratin and silver nanoparticles [63] Collagen and dextran [65] Tissue Engineering Fibrin, alginate and genipin [68] PEDOT, chitosan and gelatin [70] Polycaprolactone, silk fibroin and carbon nanotubes [71] Silk fibroin and melanin [78] Polycaprolactone and collagen [82] Gelatin, alginate and fibrinogen [88] Collagen type I and gelatin methacryloyl [89] Author Contributions: Conceptualization, K.P.V., A.B., and A.S.; writing-original draft preparation, K.P.V. ; writing-review and editing, K.P.V., A.B., and A.S.; supervision, A.B.…”