Preparation, characterization, and bioactivity of reinforced monetite with chitosan-gelatin electrospun composite scaffold for bone tissue engineering

In this study, chitosan-gelatin-monetite (CGM)-based electrospun scaffolds have been developed that closely mimicked the microstructure and chemical composition of the extracellular matrix of natural bone. CGM-based nanofibrous composite scaffolds were prepared with the help of the electrospinning technique, post-cross-linked using EDC and NHS solution to improve their stability in an aqueous environment. The prepared CG scaffold showed an average fiber diameter of 284 ± 17 nm, whereas 5 and 7 wt% monetite containing CGM5 and CGM7 scaffolds, exhibited an average fiber diameter of 390 ± 11 and 435 ± 15 nm, respectively, revealing the fine distribution of monetite particles on the fibrous surface. The distribution of monetite nanoparticles onto the CG nanofibrous surface was confirmed using XRD, FTIR, and EDAX. Moreover, the addition of 7 wt% monetite into the CG electrospun matrix increased their ultimate tensile strength from 2.01 ± 0.05 MPa in the CG scaffold to 11.68 ± 0.09 MPa in the CGM7 scaffold. SBF study and staining with ARS confirmed the higher mineralization ability of monetite-containing scaffolds compared to that revealed by the CG scaffold. The monetite incorporation into the CG matrix improved its osteogenic properties, including pre-osteoblast MG-63 cell adhesion, proliferation, and differentiation, when seeded with the cells. A higher degree of cellular adhesion, spreading, and migration was observed on the monetite-incorporated CG scaffold than that on the CG scaffold. From MTT assay, ALP activity, ARS staining, and immunocytochemistry study, the cultured cells discovered a more conducive microenvironment to proliferate and subsequently differentiate into osteoblast lineage in contact with CGM7 nanofibers rather than that in CGM0 and CGM5. In-vitro results indicated that electrospun CGM-based composite scaffolds could be used as a potential candidate to repair and regenerate new bone tissues.&#xD.

Titanium Dioxide Thin Films Obtained by Atomic Layer Deposition Promotes Osteoblasts' Viability and Differentiation Potential While Inhibiting Osteoclast Activity-Potential Application for Osteoporotic Bone Regeneration

Atomic layer deposition (ALD) technology has started to attract attention as an efficient method for obtaining bioactive, ultrathin oxide coatings. In this study, using ALD, we have created titanium dioxide (TiO2) layers. The coatings were characterised in terms of physicochemical and biological properties. The chemical composition of coatings, as well as thickness, roughness, wettability, was determined using XPS, XRD, XRR. Cytocompatibillity of ALD TiO2 coatings was accessed applying model of mouse pre-osteoblast cell line MC3T3-E1. The accumulation of transcripts essential for bone metabolism (both mRNA and miRNA) was determined using RT-qPCR. Obtained ALD TiO2 coatings were characterised as amorphous and homogeneous. Cytocompatibility of the layers was expressed by proper morphology and growth pattern of the osteoblasts, as well as their increased viability, proliferative and metabolic activity. Simultaneously, we observed decreased activity of osteoclasts. Obtained coatings promoted expression of Opn, Coll-1, miR-17 and miR-21 in MC3T3-E1 cells. The results are promising in terms of the potential application of TiO2 coatings obtained by ALD in the field of orthopaedics, especially in terms of metabolic- and age-related bone diseases, including osteoporosis.

Thermal Oxide Layer Enhances Crystallinity and Mechanical Properties for Plasma-Sprayed Hydroxyapatite Biomedical Coatings

The stability of plasma-sprayed hydroxyapatite (HA) coatings on metallic implants in vivo remains a significant challenge for load-bearing orthopedic implants despite their excellent mechanical and osteoconductive properties. This study focuses on oxide layer formation on the surface of Ti6Al4V samples through furnace heating at 600, 700, and 800 °C for 10 min for optimization of the most effective oxide layer to increase plasma coating crystallinity and improve plasma coating bond strength with the metal surface. The 800 °C heat treatment shows an effective oxide layer which increases coating crystallinity from 64 to 75% and coating adhesive bond strength from 25.9 ± 2.3 to 30.7 ± 1.1 MPa, while simultaneously reducing the dissolution rate of HA coatings. The addition of biologically relevant dopants, MgO and SiO2, show negligible effects on crystallinity and adhesive bond strength on plasma-sprayed HA coatings and additionally show an enhancement effect on osteoblast proliferation and differentiation. Moreover, the inclusion of these additivess shows an increase in osteogenesis in a rat distal femur model after 6 and 10 weeks of implantation. Overall, this study provides a direct solution to improve the crystallinity, adhesive bond strength, and osteogenic properties of plasma-sprayed HA coatings on orthopedic implants that is more manufacturable and translational from research to an industrial scale.

Preparation, characterization and bioactivities of nano anhydrous calcium phosphate added gelatin-chitosan scaffolds for bone tissue engineering

Gelatin, chitosan and nano calcium phosphate based composite scaffold with tailored architectures and properties has great potential for bone regeneration. Herein, we aimed to improve the physico chemical, mechanical and osteogenic properties of 3D porous scaffold by incorporation of dihydrogen calcium phosphate anhydrous (DCPA) nanoparticles into biopolymer matrix with variation in composition in the prepared scaffolds. Scaffolds were prepared from the slurry containing gelatin, chitosan and synthesized nano DCPA particle using lyophilization technique. DCPA nano particles were synthesized using calcium carbonate and phosphoric acid in water-ethanol medium. XRD pattern showed phase pure DCPA in synthesized nanopowder. Scaffolds were prepared by addition of DCPA nanoparticles to the extent of 5-10 wt% of total polymer into gelatin-chitosan solution with solid loading varying between 2.5 and 2.75 wt%. The prepared scaffold showed interconnected porosity with pore size varying between 110 and 200 micrometer. With addition of DCPA nanoparticles, average pore size of the prepared scaffolds decreased. With increase in nano ceramic phase content from 5 wt% to 10 wt% of total polymer, the compressive strength of the scaffold increased. Scaffold containing 10 wt% DCPA showed the highest average compressive strength of 2.2 MPa. Higher cellular activities were observed in DCPA containing scaffolds as compared to pure gelatin chitosan scaffold suggesting the fact that nano DCPA addition into the scaffold promoted better osteoblast adhesion and proliferation as evident from MTT assay and scanning electron microscopic (SEM) investigation of osteoblast cultured scaffolds. A higher degree of lamellopodia and filopodia extensions and better spreading behavior of osteoblasts were observed in FESEM micrographs of MG 63 cultured DCPA containing scaffold. The results demonstrated that both mechanical strength and osteogenic properties of gelatin-chitosan scaffold could be improved by addition of anhydrous dihydrogen calcium phosphate nanoparticles into it.