Synergistic Effect of PVDF-Coated PCL-TCP Scaffolds and Pulsed Electromagnetic Field on Osteogenesis

Bone exhibits piezoelectric properties. Thus, electrical stimulations such as pulsed electromagnetic fields (PEMFs) and stimuli-responsive piezoelectric properties of scaffolds have been investigated separately to evaluate their efficacy in supporting osteogenesis. However, current understanding of cells responding under the combined influence of PEMF and piezoelectric properties in scaffolds is still lacking. Therefore, in this study, we fabricated piezoelectric scaffolds by functionalization of polycaprolactone-tricalcium phosphate (PCL-TCP) films with a polyvinylidene fluoride (PVDF) coating that is self-polarized by a modified breath-figure technique. The osteoinductive properties of these PVDF-coated PCL-TCP films on MC3T3-E1 cells were studied under the stimulation of PEMF. Piezoelectric and ferroelectric characterization demonstrated that scaffolds with piezoelectric coefficient d33 = −1.2 pC/N were obtained at a powder dissolution temperature of 100 °C and coating relative humidity (RH) of 56%. DNA quantification showed that cell proliferation was significantly enhanced by PEMF as low as 0.6 mT and 50 Hz. Hydroxyapatite staining showed that cell mineralization was significantly enhanced by incorporation of PVDF coating. Gene expression study showed that the combination of PEMF and PVDF coating promoted late osteogenic gene expression marker most significantly. Collectively, our results suggest that the synergistic effects of PEMF and piezoelectric scaffolds on osteogenesis provide a promising alternative strategy for electrically augmented osteoinduction. The piezoelectric response of PVDF by PEMF, which could provide mechanical strain, is particularly interesting as it could deliver local mechanical stimulation to osteogenic cells using PEMF.

A New Method in Attribution? Attempts of the Employment of Geometric Morphometrics in the Attribution of Late Archaic Attic Lekythoi

In the Late Archaic - Early Classic period, the Attic ceramic industry was characterized by a kind of duality. On the one hand, the red-figure technique was flourishing, when Euphronios’, Douris’ or the Berlin Painter’s works represented the height of Greek vase painting. On the other hand, the market was also covered by large quantities of low-quality black-figure pottery. Not only in Athens, but even in the whole Ancient Mediterranean these mass-produced vessels emerge constantly, even from modern excavations. Therefore, in contrast to most vases of more talented painters they can be attached to an archaeological feature or layer. Due to their inadequate style, relatively few characteristics can be determined while looking at the painting. Thus, the manufacturing criteria, such as the details of the shapes, are more important in the attribution. In this paper, I study the late black-figure lekythoi of the Museum of Fine Arts in Budapest with the help of geometric morphometrics using 3D reconstructions.

The Effect of the Isomeric Chlorine Substitutions on the Honeycomb-Patterned Films of Poly(x-chlorostyrene)s/Polystyrene Blends and Copolymers via Static Breath Figure Technique

Polymeric thin films patterned with honeycomb structures were prepared from poly(x-chlorostyrene) and statistical poly(x-chlorostyrene-co-styrene) copolymers by static breath figure method. Each polymeric sample was synthesized by free radical polymerization and its solution in tetrahydrofuran cast on glass wafers under 90% relative humidity (RH). The effect of the chorine substitution in the topography and conformational entropy was evaluated. The entropy of each sample was calculated by using Voronoi tessellation. The obtained results revealed that these materials could be a suitable toolbox to develop a honeycomb patterns with a wide range of pore sizes for a potential use in contact guidance induced culture.

Fabrication of honeycomb films from highly functional dendritic structures: electrostatic force driven immobilization of biomolecules

Herein we report the preparation of honeycomb porous films for selective immobilization of biomolecules via the breath figure technique, a water-assisted micropatterning method.

Highly Ordered Honeycomb Film Formation of Linear Polymers by the Breath Figure Technique

Highly ordered, porous honeycomb (HC) films were prepared by the breath figure technique from linear polymers poly(methyl methacrylate) (PMMA) and polystyrene (PS). Typically HC films are difficult to form from such simple linear polymers. The addition of a novel fluorinated polymer (FP) additive with as little as 1 wt-% to PMMA or 5 wt-% to PS was required to obtain regular porous HC films. Through investigation of the influence of the additive on the polymer properties, three parameters based on interfacial tension, polymer solution viscosity, and polymer solidification rate were identified as key factors affecting the ability of polymer systems to form regular porous HC films. A new hypothesis was subsequently developed based on the relationships of these parameters to explain the unusual behaviour associated with HC film formation from linear PMMA and PS with addition of FP additive. This work will provide a new tool to guide the formation of HC films and will greatly broaden the range of polymers used to form HC films in the future.