A comparison study between electrospun polycaprolactone and piezoelectric poly(3-hydroxybutyrate-co-3-hydroxyvalerate) scaffolds for bone tissue engineering

This study was supported by the Federal Target Program #14.587.21.0013 (a unique application number 2015-14-588-0002-5599)

Influence of deposition conditions on the composition, texture and microstructure of RF-magnetron sputter-deposited hydroxyapatite thin films

In this study, nanostructured hydroxyapatite (HA) coatings were deposited at a constant power via radio frequency magnetron sputtering. Substrate rotation was applied to increase the uniformity of the thin film properties. The crystallographic orientation, composition and microstructure of the coatings were examined. The characteristics of the deposited coatings associated with the applied deposition conditions were evaluated as a function of time that the samples spent under the target racetrack. The obtained thin films exhibit a change in out-of-plane orientation from preferential (002) to (300) and an increase in the Ca/P molar ratio when exposed for a longer time under the racetrack. This introduces the possibility of tuning crystallographic orientations of HA coatings

Plasmonic hybrid biocomposite as an effective substrate for detection of biomolecules by surface-enhanced Raman spectroscopy

The enhancement of the Raman light scattering signal from the surface of the porous hybrid biocomposites based on polyhydroxybutyrate (PHB), calcium carbonate (CaCO3), and nanoplasmonic Ag particles is investigated. Based on PHB, fibrous scaffolds are obtained by the electrospinning technique. The fibrous scaffolds have been covered by CaCO3 and Ag nanoparticles by means of mineralization in salt solutions and Ag reduction reaction. Successful formation of the CaCO3 and Ag nanoparticles on the scaffold surface has been confirmed by the data of scanning electron microscopy, x-ray diffraction analysis, and infrared spectroscopy. Surface-enhanced Raman spectroscopy (SERS) of the obtained sample surface has demonstrated a significant enhancement of the Rhodamine 6G signal (Ef > 105) in comparison with the reference sample where the analyte concentration and the laser power were 100 times higher. Thus, the present research has confirmed prospects for the application of biocomposites based on polyhydroxybutyrate for detection and investigation of biomolecules by the SERS method

Piezoelectric 3-D fibrous poly(3-hydroxybutyrate)-based scaffolds ultrasound-mineralized with calcium carbonate for bone tissue engineering : inorganic phase formation, osteoblast cell adhesion, and proliferation

Elaboration of novel biocomposites providing simultaneously both biodegradability and stimulated bone tissue repair is essential for regenerative medicine. In particular, piezoelectric biocomposites are attractive because of a possibility to electrically stimulate cell response. In the present study, novel CaCO3-mineralized piezoelectric biodegradable scaffolds based on two polymers, poly[(R)3-hydroxybutyrate] (PHB) and poly[3-hydroxybutyrate-co-3-hydroxyvalerate] (PHBV), are presented. Mineralization of the scaffold surface is carried out by the in situ synthesis of CaCO3 in the vaterite and calcite polymorphs using ultrasound (U/S). Comparative characterization of PHB and PHBV scaffolds demonstrated an impact of the porosity and surface charge on the mineralization in a dynamic mechanical system, as no essential distinction was observed in wettability, structure, and surface chemical compositions. A significantly higher (4.3 times) piezoelectric charge and a higher porosity (similar to 15%) lead to a more homogenous CaCO3 growth in 3-D fibrous structures and result in a two times higher relative mass increase for PHB scaffolds compared to that for PHBV. This also increases the local ion concentration incurred upon mineralization under U/S-generated dynamic mechanical conditions. The modification of the wettability for PHB and PI-BV scaffolds from hydrophobic (nonmineralized fibers) to superhydrophilic (mineralized fibers) led to a pronounced apatite-forming behavior of scaffolds in a simulated body fluid. In turn, this results in the formation of a dense monolayer of well-distributed and proliferated osteoblast cells along the fibers. CaCO3-mineralized PHBV surfaces had a higher osteoblast cell adhesion and proliferation assigned to a higher amount of CaCO3 on the surface compared to that on PHB scaffolds, as incurred from micro-computed tomography (mu CT). Importantly, a cell viability study confirmed biocompatibility of all the scaffolds. Thus, hybrid biocomposites based on the piezoelectric PHB polymers represent an effective scaffold platform functionalized by an inorganic phase and stimulating the growth of the bone tissue