3D biodegradable scaffolds of polycaprolactone with silicate-containing hydroxyapatite microparticles for bone tissue engineering: high-resolution tomography and in vitro study

To date, special interest has been paid to composite scaffolds based on polymers enriched with hydroxyapatite (HA). However, the role of HA containing different trace elements such as silicate in the structure of a polymer scaffold has not yet been fully explored. Here, we report the potential use of silicate-containing hydroxyapatite (SiHA) microparticles and microparticle aggregates in the predominant range from 2.23 to 12.40 µm in combination with polycaprolactone (PCL) as a hybrid scaffold with randomly oriented and well-aligned microfibers for regeneration of bone tissue. Chemical and mechanical properties of the developed 3D scaffolds were investigated with XRD, FTIR, EDX and tensile testing. Furthermore, the internal structure and surface morphology of the scaffolds were analyzed using synchrotron X-ray µCT and SEM. Upon culturing human mesenchymal stem cells (hMSC) on PCL-SiHA scaffolds, we found that both SiHA inclusion and microfiber orientation affected cell adhesion. The best hMSCs viability was revealed at 10 day for the PCL-SiHA scaffolds with well-aligned structure (~82%). It is expected that novel hybrid scaffolds of PCL will improve tissue ingrowth in vivo due to hydrophilic SiHA microparticles in combination with randomly oriented and well-aligned PCL microfibers, which mimic the structure of extracellular matrix of bone tissue

Influence of Calcium-Phosphate Coating on Wettability of Hybrid Piezoelectric Scaffolds

Herein, electrospun biodegradable scaffolds based on polycaprolactone (PCL), poly(3-hydroxybutyrate) (PHB) and polyaniline (PANi) polymers were fabricated. A calcium-phosphate (CaP) coating was deposited on the surface of the scaffolds via an improved soaking process. Influence of the deposition cycles and ethanol concentration in the solution on the relative increase of the scaffolds weight and water contact angle (WCA) are determined. The characterization of the molecular and crystal structure confirmed the formation of CaP phase. Importantly, WCA results showed that the pristine scaffolds have the hydrophobic surface, while the deposition of CaP coating onto scaffolds allows to significantly improve the surface wetting behavior, and infiltration of the water droplets into the CaP-coated scaffolds was observed. Thus, the fabricated hybrid biodegradable piezoelectric scaffolds can be utilized for regenerative medicine

Core-shell magnetoactive PHB/gelatin/magnetite composite electrospun scaffolds for biomedical applications

Novel hybrid magnetoactive composite scaffolds based on poly(3-hydroxybutyrate) (PHB), gelatin, and magnetite (Fe3O4) were fabricated by electrospinning. The morphology, structure, phase composition, and magnetic properties of composite scaffolds were studied. Fabrication procedures of PHB/gelatin and PHB/gelatin/Fe3O4 scaffolds resulted in the formation of both core-shell and ribbon-shaped structure of the fibers. In case of hybrid PHB/gelatin/Fe3O4 scaffolds submicron-sized Fe3O4 particles were observed in the surface layers of the fibers. The X-ray photoelectron spectroscopy results allowed the presence of gelatin on the fiber surface (N/C ratio–0.11) to be revealed. Incubation of the composite scaffolds in saline for 3 h decreased the amount of gelatin on the surface by more than ~75%. The differential scanning calorimetry results obtained for pure PHB scaffolds revealed a characteristic melting peak at 177.5 °C. The presence of gelatin in PHB/gelatin and PHB/gelatin/Fe3O4 scaffolds resulted in the decrease in melting temperature to 168–169 °C in comparison with pure PHB scaffolds due to the core-shell structure of the fibers. Hybrid scaffolds also demonstrated a decrease in crystallinity from 52.3% (PHB) to 16.9% (PHB/gelatin) and 9.2% (PHB/gelatin/Fe3O4). All the prepared scaffolds were non-toxic and saturation magnetization of the composite scaffolds with magnetite was 3.27 ± 0.22 emu/g, which makes them prospective candidates for usage in biomedical applications

Author Correction: 3D biodegradable scaffolds of polycaprolactone with silicate-containing hydroxyapatite microparticles for bone tissue engineering: high-resolution tomography and in vitro study

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper

Electrospun magnetic composite poly-3-hydroxybutyrate/magnetite scaffolds for biomedical applications: composition, structure, magnetic properties, and biological performance

Magnetically responsive composite polymer scaffolds have good potential for a variety of biomedical applications. In this work, electrospun composite scaffolds made of polyhydroxybutyrate (PHB) and magnetite (Fe3O4) particles (MPs) were studied before and after degradation in either PBS or a lipase solution. MPs of different sizes with high saturation magnetization were synthesized by the coprecipitation method followed by coating with citric acid (CA). Nanosized MPs were prone to magnetite-maghemite phase transformation during scaffold fabrication, as revealed by Raman spectroscopy; however, for CA-functionalized nanoparticles, the main phase was found to be magnetite, with some traces of maghemite. Submicron MPs were resistant to the magnetite-maghemite phase transformation. MPs did not significantly affect the morphology and diameter of PHB fibers. The scaffolds containing CA-coated MPs lost 0.3 or 0.2% of mass in the lipase solution and PBS, respectively, whereas scaffolds doped with unmodified MPs showed no mass changes after 1 month of incubation in either medium. In all electrospun scaffolds, no alterations of the fiber morphology were observed. Possible mechanisms of the crystalline-lamellar-structure changes in hybrid PHB/Fe3O4 scaffolds during hydrolytic and enzymatic degradation are proposed. It was revealed that particle size and particle surface functionalization affect the mechanical properties of the hybrid scaffolds. The addition of unmodified MPs increased scaffolds' ultimate strength but reduced elongation at break after the biodegradation, whereas simultaneous increases in both parameters were observed for composite scaffolds doped with CA-coated MPs. The highest saturation magnetization-higher than that published in the literature-was registered for composite PHB scaffolds doped with submicron MPs. All PHB scaffolds proved to be biocompatible, and the ones doped with nanosized MPs yielded faster proliferation of rat mesenchymal stem cells. In addition, all electrospun scaffolds were able to support angiogenesis in vivo at 30 days after implantation in Wistar rats

Piezoelectric Response in Hybrid Micropillar Arrays of Poly(Vinylidene Fluoride) and Reduced Graphene Oxide

International audienceThis study was dedicated to the investigation of poly(vinylidene fluoride) (PVDF) micropillar arrays obtained by soft lithography followed by phase inversion at a low temperature. Reduced graphene oxide (rGO) was incorporated into the PVDF as a nucleating filler. The piezoelectric properties of the PVDF-rGO composite micropillars were explored via piezo-response force microscopy (PFM). Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) showed that α, β, and γ phases co-existed in all studied samples, with a predominance of the γ phase. The piezoresponse force microscopy (PFM) data provided the local piezoelectric response of the PVDF micropillars, which exhibited a temperature-induced downward dipole orientation in the pristine PVDF micropillars. The addition of rGO into the PVDF matrix resulted in a change in the preferred polarization direction, and the piezo-response phase angle changed from -120° to 20°-40°. The pristine PVDF and PVDF loaded with 0.1 wt % of rGO after low-temperature quenching were found to possess a piezoelectric response of 86 and 87 pm/V respectively, which are significantly higher than the |d33eff| in the case of imprinted PVDF 64 pm/V. Thus, the addition of rGO significantly affected the domain orientation (polarization) while quenching increased the piezoelectric response

Review of Hybrid Materials Based on Polyhydroxyalkanoates for Tissue Engineering Applications

This review is focused on hybrid polyhydroxyalkanoate-based (PHA) biomaterials with improved physico-mechanical, chemical, and piezoelectric properties and controlled biodegradation rate for applications in bone, cartilage, nerve and skin tissue engineering. PHAs are polyesters produced by a wide range of bacteria under unbalanced growth conditions. They are biodegradable, biocompatible, and piezoelectric polymers, which make them very attractive biomaterials for various biomedical applications. As naturally derived materials, PHAs have been used for multiple cell and tissue engineering applications; however, their widespread biomedical applications are limited due to their lack of toughness, elasticity, hydrophilicity and bioactivity. The chemical structure of PHAs allows them to combine with other polymers or inorganic materials to form hybrid composites with improved structural and functional properties. Their type (films, fibers, and 3D printed scaffolds) and properties can be tailored with fabrication methods and materials used as fillers. Here, we are aiming to fill in a gap in literature, revealing an up-to-date overview of ongoing research strategies that make use of PHAs as versatile and prospective biomaterials. In this work, a systematic and detailed review of works investigating PHA-based hybrid materials with tailored properties and performance for use in tissue engineering applications is carried out. A literature survey revealed that PHA-based composites have better performance for use in tissue regeneration applications than pure PHA

Effect of van der Waals interactions on the adhesion strength at the interface of the hydroxyapatite-titanium biocomposite : a first-principles study

Hydroxyapatite (HAP) is frequently used as biocompatible coating on Ti-based implants. In this context, the HAP-Ti adhesion is of crucial importance. Here, we report ab initio calculations to investigate the influence of Si incorporation into the amorphous calcium-phosphate (a-HAP) structure on the interfacial bonding mechanism between the a-HAP coating and an amorphous titanium dioxide (a-TiO(2)) substrate, contrasting two different density functionals: PBE-GGA, and DFT-D3, which are capable of describing the influence of the van der Waals (vdW) interactions. In particular, we discuss the effect of dispersion on the work of adhesion (W(ad)), equilibrium geometries, and charge density difference (CDD). We find that replacement of P by Si in a-HAP (a-Si-HAP) with the creation of OH vacancies as charge compensation results in a significant increase in the bond strength between the coating and substrate in the case of using the PBE-GGA functional. However, including the vdW interactions shows that these forces considerably contribute to the W(ad). We show that the difference (W(ad) − W(ad)(vdW)) is on average more than 1.1 J m(−2) and 0.5 J m(−2) for a-HAP/a-TiO(2) and a-Si-HAP/a-TiO(2), respectively. These results reveal that including vdW interactions is essential for accurately describing the chemical bonding at the a-HAP/a-TiO(2) interface