Fibrous scaffolds have become popular in tissue engineering (TE) due to their morphological resemblance to extracellular matrix components. While electrospinning is the most common technique in the field, solution blow spinning is an emerging technique with great potential. One of its many advantages is that it can produce aligned fibers with a very simple experimental setup. This work aimed to fabricate poly(ε‐caprolactone) mats with aligned fibers and compare them to nonaligned ones. For that, samples were produced using three rotational speeds of a cylindrical collector and characterized in terms of fiber alignment and diameter, mechanical properties, wettability, and biological response. Results showed that with a static collector, fibers were randomly deposited and nonaligned. As the speed was increased, the fibers began to align (as proven by image analysis), resulting in a change in mechanical behavior, but no differences in fiber diameter. Cells cultured on aligned samples were more elongated, and a higher alignment degree seemed to favor cellular growth. The results confirmed the potential of this up‐and‐coming technique to produce aligned fibers for TE. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1462–1470, 2019.

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.

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.

Although prosthetic heart valves have saved many lives, the search for a living substitute continues with the aid of tissue engineering. Much progress has been made so far, but the translation of this technology to clinical reality remains a challenge, especially due to the structural complexity of heart valves and the harsh environment they are in. In a joint effort, researchers from Federal University of ABC and Institute Dante Pazzanese of Cardiology have conceived a new bioresorbable scaffold for heart valve tissue engineering (HVTE), whose hydrodynamic performance was first assessed and described in this work. The scaffold was studied at the mitral position of a left heart simulator from Escola Politécnica of the University of São Paulo, under 60 bpm and with no cell seeding. In this condition, two-dimensional particle image velocimetry was performed to investigate the flow during diastolic and systolic phases. The results indicate that the scaffold can withstand the required intraventricular pressures for a simulated normal physiologic condition in a bioreactor. Furthermore, the averaged (N = 150) velocity vector maps showed a smooth and well-distributed flow during diastole and qualitatively demonstrated no-significant regurgitation at systole.

No abstract