The objective of this study was to evaluate Vero cells in in vitro biocompatibility tests with pure PHBV and PCL and 75/25 and 50/50 blends developed for bone tissue bioengineering in dense or porous forms. The biomaterials were characterized morphologically by scanning electron microscopy, (SEM) stereoscopic imaging (SI), and micrometer measurement. Cellular assay was made by MTT, morphological and cytochemistry analysis. The dense and porous scaffolds presented irregular surfaces. SEM allowed to observe details of the irregular surface throughout the dense samples and confirmed the absence of pores. It was found interconnected pores on porous samples. The porous samples were thicker than the dense samples. None of the polymers was considered toxic. Lower activity measured by MTT was observed for the 50/50 blends, suggesting a slower cell adhesion pattern. The cells were able to spread almost throughout the surface of the polymers, even into the pores. The dense and porous 50/50 samples were so brittle and difficult handling. Except for the 50/50 blends, the polymers were generally good substrates for the cells, were non-toxic, and exhibited the recommended morphological features. In addition, these biomaterials did not inhibit specific biological responses identified at the cytochemical level.

Abstract Introduction Solution blow spinning (SBS) and airbrushing are two techniques that can be used as alternatives to electrospinning in the production of fibrous scaffolds for tissue engineering (TE). SBS seems particularly interesting due to its versatility, however, it has not been much explored and no automated SBS systems were found in the literature. Therefore, the present work aimed to develop such equipment and compare the results to those found for airbrushing, considering the same set of parameters. Methods A new SBS set up, composed of a specially designed nozzle with automated movement, a syringe pump and a compressor, was used to produce fibrous poly (ε-caprolactone) (PCL) mats. The airbrushed fibers were produced under the same conditions, and samples of both types of mats were imaged using scanning electron microscopy (SEM) to compare them in terms of microstructure and fiber diameter. Results The SBS system was robust and performed well, in terms of movement and fiber deposition. In comparison to airbrushing’s, SBS mats presented different microstructural characteristics (considering the parameters used). Conclusion The biggest advantage over airbrushing may be its versatility and simple automation, which may improve sample reproducibility, especially considering scaled up processes. To further improve this apparatus, a better understanding of how process variables interfere in the microstructure is needed, as well as more sophisticated interface and operation.

Dense and porous polyHEMA hydrogels were synthesized by bulk and solution radical-initiated polymerization techniques. The morphologic analysis (SEM) of obtained hydrogels showed an amorphous dense structure for the samples obtained by bulk polymerization and a porous structure with non connected porous as a result of bulk polymerization in the presence of water soluble crystals (sucrose/NaCl). The use of solution polymerization technique using different amounts of water as diluent resulted in the formation of a sponge-like structure with connected microporous in case of using water amount equal or higher than 57.5%. The saline solution uptake and dynamic mechanical behavior of dense hydrogels were influenced by the amount of crosslinking between the polymer chains.