Fabrication and examination of polyorganophosphazene/polycaprolactone-based scaffold with degradation, in vitro and in vivo behaviors suitable for tissue engineering applications

The present study aimed to synthesis a proper scaffold consisting of hydroxylated polyphosphazene and polycaprolactone (PCL), focusing on its potential use in tissue engineering applications. The first grafting of PCL to poly(propylene glycol)phosphazene (PPGP) was performed via ROP of ε-caprolactone, whereas PPGP act as a multisite macroinitiator. The prepared poly(propylene glycol phosphazene)-graft-polycaprolactone (PPGP-g-PCL) were evaluated by essential tests, including NMR, FTIR, FESEM-EDS, TGA, DSC and contact angle measurement. The quantum calculations were performed to investigate molecular geometry and its energy, and HOMO and LUMO of PPGP-g-PCL in Materials Studio2017. MD simulations were applied to describe the interaction of the polymer on phospholipid membrane (POPC128b) in Material Studio2017. The C2C12 and L929 cells were used to probe the cell-surface interactions on synthetic polymers surfaces. Cells adhesion and proliferation onto scaffolds were evaluated using FESEM and MTT assay. In vitro analysis indicated enhanced cell adhesion, high proliferation rate, and excellent viability on scaffolds for both cell types. The polymer was further tested via intraperitoneal implantation in mice that showed no evidence of adverse inflammation and necrosis at the site of the scaffold implantation; in return, osteogenesis, new-formed bone and in vivo degradation of the scaffold were observed. Herein, in vitro and in vivo assessments confirm PPGP-g-PCL, as an appropriate scaffold for tissue engineering applications.

Hybrid porous zirconia scaffolds fabricated using additive manufacturing for bone tissue engineering applications

For the formation of new bone in critical-sized bone defects, bioactive scaffolds with an interconnected porous network are necessary. Herein, we fabricated three-dimensional (3D) porous hybrid zirconia scaffolds to promote hybrid functionality, i.e., excellent mechanical properties and bioactive performance. Specifically, the 3D printed scaffolds were subjected to Zn-HA/glass composite coating on glass-infiltrated zirconia (ZC). In addition, to pertain the extracellular matrix of bone, biopolymer (alginate/gelatine) was embedded in a developed 3D construct (ZB and ZCB). A zirconia-printed scaffold (Z) group served as a control. The structural and mechanical properties of the constructed scaffolds were studied using essential characterization techniques. Furthermore, the biological performance of the designed scaffolds was tested by a sequence of in vitro cell tests, including the attachment, proliferation, and osteogenic differentiation of dental pulp cells (DPCs). The ZC and ZCB scaffolds exhibited 20% higher compression strength than the zirconia (Z) scaffolds. More importantly, the ZC constructs exhibited superior cell-adhesion, distribution, and osteogenic differentiation ability due to the synergistic effects of the composite coating. In addition, the biopolymer-embedded scaffolds (ZB, ZCB) showed an excellent biological and mechanical performance. Thus, our results suggest that the Zn-HA/glass composite-coated glass-infiltrated zirconia (ZC, ZCB) scaffolds are a dynamic approach to designing bioactive 3D scaffolds for the load-bearing bone regeneration applications.

Chitosan-laponite nanocomposite scaffolds for wound dressing application

The pivotal issue of skin regeneration research is the development of effective biomaterials that exhibit biological activities as fungicide and bactericide, combining simple and low cost manufacturing technologies. In this context, nanocomposite scaffolds based on chitosan (Ch)/Laponite (Lap) were produced by using different concentrations of Lap via freeze-drying process for potential application in skin regeneration. The influence of Lap concentration on the scaffold properties was evaluated. The prepared scaffolds were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), porosity, swelling capacity, and mechanical analyses. The results revealed that the scaffolds exhibited a porous architecture, besides the increase in the clay content, leads to an increase in the porosity, an improvement of mechanical strength, and a decrease of swelling capacity. In vitro tests were also carried out to evaluate the biocompatibility of the materials, such as bioadhesion, antibacterial activity, viability, and cell adhesion. Viability and cell adhesion demonstrated that all scaffolds were not cytotoxic and the fibroblast cells readily attached on the surface of the scaffolds. Thereby, the results suggested that the nanocomposite scaffolds are biomaterials potentially useful as wound dressings.

Enhancing the mechanical and in vitro performance of robocast bioglass scaffolds by polymeric coatings: Effect of polymer composition

The effect of different polymeric coatings, including natural and synthetic compositions, on the mechanical performance of 45S5 bioglass robocast scaffolds is systematically analyzed in this work. Fully amorphous 45S5 bioglass robocast scaffolds sintered at 550 °C were impregnated with natural (gelatin, alginate, and chitosan) and synthetic (polycaprolactone, PCL and poly-lactic acid, PLA) polymers through a dip-coating process. Mechanical enhancement provided by these coatings in terms of both compressive strength and strain energy density was evaluated. Natural polymers, in general, and chitosan, in particular, were found to produce the greater reinforcement. The effect of these coatings on the in vitro bioactivity and degradation behavior of 45S5 bioglass robocast scaffolds was also investigated through immersion tests in simulated body fluid (SBF). Coatings from natural polymers, especially chitosan, are shown to have a positive effect on the bioactivity of 45S5 bioglass, accelerating the formation of an apatite-like layer. Besides, most coating compositions reduced the degradation (weight loss) rate of the scaffold, which has a positive impact on the evolution of their mechanical properties.

The facile synthesis and bioactivity of a 3D nanofibrous bioglass scaffold using an amino-modified bacterial cellulose template

Porous bioglass (BG) scaffolds are of great importance in tissue engineering because of their excellent osteogenic properties for bone regeneration. Herein, we reported for the first time the use of amino-modified bacterial cellulose (NBC) as a template to prepare a three-dimensional (3D) nanofibrous BG scaffold by a facile modified sol-gel approach under ultrasonic treatment. The results suggested that the amino groups on the BC template could effectively promote the absorption of the deposited CaO and SiO2 precursors, and the as-obtained BG scaffold showed a 3D interconnected porous network structure consisting of nanofibers with a diameter of about 20 nm. Furthermore, the as-obtained BG scaffold showed very good bioactivity after being immersed in SBF for 7 days. This research provides a facile and efficient way to prepare a nanofibrous BG scaffold with 3D porous structure, which can be used as a promising candidate for biomedical applications.

Tailor made alginate hydrogel for local infection prophylaxis in orthopedic applications

Preventing implants associated infections is crucial in orthopedics. Local delivery of antibiotics through implants is a promising strategy to solve this issue. In this study, alginate is tailored to control its swelling, entrapment and release of ciprofloxacin (antibiotic) through the formation of interpenetrating polymer network and composite matrices using gelatin and hydroxyapatite. Developed matrices were characterized by Fourier transform infrared spectroscopy, x-ray diffraction and scanning electron microscopy. The individual tailoring approaches exerted significant influence on the swelling behavior of alginate matrix consequently enhanced the drug entrapment and extended the release period. However, the alginate matrix tailored with the combined approaches resulted in a superior matrix, which had a better control over the burst release of ciprofloxacin. Drug release prolonged from 5h to 240h for composite matrix as compared with alginate matrix showing that alginate combined with gelatin and hydroxyapatite sustained the release for longer periods. This matrix revealed excellent biocompatibility with osteoblast like MG-63 cell lines and showed good antibacterial activity against S. aureus and E. coli.

Enhancing the biological properties of carbon nanofibers by controlling the crystallization of incorporated bioactive glass via silicon content

Mechanism and model of biomineralization behavior of CNF and CNF/BG hybrids containing BG with different silicon contents.

Fabrication of a composite of nanocrystalline carbonated hydroxyapatite (cHAP) with polylactic acid (PLA) and its surface topographical structuring with direct laser writing (DLW)

The fabrication of a polylactic acid (PLA)–carbonated hydroxyapatite (cHAP) composite material from synthesised phase pure nano-cHAP and melted PLA by mechanical mixing at 220–235 °C has been developed in this study.

Regulating micro-structure and biomineralization of electrospun PVP-based hybridized carbon nanofibers containing bioglass nanoparticles via aging time

Morphological and micro-structural evolution of BG components in PVP-based CNF/BG composite with aging time.

Thermal-based regulation on biomineralization and biological properties of bioglass nanoparticles decorated PAN-based carbon nanofibers

The mechanism and model for biomineralization behavior and cell culture of CNF/BG sintered at various temperatures.

Synthesis of water-dispersible silicon-containing hydroxyapatite nanoparticles with adjustable degradation rates and their applications as pH-responsive drug carriers

An environmentally friendly method was developed to synthesize water-dispersible Si-HAp nanoparticles with adjustable degradation rates, high loading capacities for anticancer drugs, and sustained and pH-dependent drug release properties.