Advances in tissue engineering have made possible the construction of organs and tissues with the use of biomaterials and cells. Three important elements are considered: a specific cell culture, an adequate environment, and a scaffold. The present study aimed to develop P3HB scaffolds by 3D printing and evaluate their biocompatibility with HaCaT epidermal cells, as a potential model that allows the formation of functional tissue. By using a method of extraction and purification with ethanol and acetone, a biopolymer having suitable properties for use as a tissue support was obtained. This polymer exhibited a higher molecular weight (1500 kDa) and lower contact angle (less than 90°) compared to the material obtained using the conventional method. The biocompatibility analysis reveals that the scaffold obtained using the ethanol–acetone method and produced by 3D printing without pores was not cytotoxic, did not self-degrade, and allowed high homogenous cell proliferation of HaCaT cells. In summary, it is possible to conclude that the P3HB scaffold obtained by 3D printing and a simplified extraction method is a suitable support for the homogeneous development of HaCaT keratinocyte cell lineage, which would allow the evaluation of this material to be used as a biomatrix for tissue engineering.

In the present work, we developed hybrid nanostructures based on ZnO films deposited on macroporous silicon substrates using the sol–gel spin coating and ultrasonic spray pyrolysis (USP) techniques. The changes in the growth of ZnO films on macroporous silicon were studied using a UV-visible spectrometer, an X-ray diffractometer (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). XRD analysis revealed the beneficial influence of macroporous silicon on the structural properties of ZnO films. SEM micrographs showed the growth and coverage of ZnO granular and flake-like crystals inside the pores of the substrate. The root mean square roughness (RMS) measured by AFM in the ZnO grown on the macroporous silicon substrate was up to one order of magnitude higher than reference samples. These results prove that the methods used in this work are effective to cover porous and obtain nano-morphologies of ZnO. These morphologies could be useful for making highly sensitive gas sensors.

Ni-based superalloys are materials utilized in high-performance services that demand excellent corrosion resistance and mechanical properties. Its usages can include fuel storage, gas turbines, petrochemistry, and nuclear reactor components, among others. On the other hand, hydrogen (H), in contact with metallic materials, can cause a phenomenon known as hydrogen embrittlement (HE), and its study related to the superalloys is fundamental. This is related to the analysis of the solubility, diffusivity, and permeability of H and its interaction with the bulk, second-phase particles, grain boundaries, precipitates, and dislocation networks. The aim of this work was mainly to study the effect of chromium (Cr) content on H diffusivity in Ni-based superalloys; additionally, the development of predictive models using artificial intelligence. For this purpose, the permeability test was employed based on the double cell experiment proposed by Devanathan–Stachurski, obtaining the effective diffusion coefficient (D_eff), steady-state flux (J_ss), and the trap density (N_T) for the commercial and experimentally designed and manufactured Ni-based superalloys. The material was characterized with energy-dispersed X-ray spectroscopy (EDS), atomic absorption, CHNS/O chemical analysis, X-ray diffraction (XRD), brightfield optical microscopy (OM), and scanning electron microscopy (SEM). On the other hand, predictive models were developed employing artificial neural networks (ANNs) using experimental results as a database. Furthermore, the relative importance of the main parameters related to the H diffusion was calculated. The D_eff, J_ss, and N_T achieved showed relatively higher values considering those reported for Ni alloys and were found in the following orders of magnitude: [1 × 10⁻⁸, 1 × 10⁻¹¹ m²/s], [1 × 10⁻⁵, 9 × 10⁻⁷ mol/cm²s], and [7 × 10²⁵ traps/m³], respectively. Regarding the predictive models, linear correlation coefficients of 0.96 and 0.80 were reached, corresponding to the D_eff and J_ss. Due to the results obtained, it was suitable to dismiss the effect of Cr in solid solution on the H diffusion. Finally, the predictive models developed can be considered for the estimation of D_eff and J_ss as functions of the characterized features.

Zn-Ag-Cu alloys have recently attracted attention as alloy candidates for biomedical applications, but, to date, they have not achieved the required mechanical properties. To improve the mechanical properties of Zn-Ag-Cu-base alloys, in this work, the effects of the presence of increasing amounts of Ag and Cu as alloying elements on the properties of four 0.05% Mg-micro-alloyed Zn-Ag-Cu base alloys are explored. The alloys were manufactured in an electric furnace with a protective atmosphere using increasing amounts of Ag and Cu as alloying agents, and were cast in a metallic mold. The samples obtained were thermomechanically processed by hot extrusion. Three of the four alloys under study presented increasing amounts of the second phase (Ag, Cu)Zn₄, high mechanical properties, a microstructure and mechanical behavior characteristic of heteromaterials with a heterogeneous lamella-structure, and met the requirements of the mechanical properties, corrosion rate, antibacterial properties against S. aureus, and the cytotoxicity required for biomedical applications. It seems possible to tune the properties of the ZnAgCu-0.05% Mg alloys by changing the Ag and Cu contents.

The skin is the largest organ and one of the most important in the human body, and is constantly exposed to pathogenic microorganisms that cause infections; then, pharmacological administration is required. One of the basic medical methods for treating chronic wounds is to use topical dressings with characteristics that promote wound healing. Fiber-based dressings mimic the local dermal extracellular matrix (ECM), maintaining an ideal wound-healing climate. This work proposes electrospun PHB/PEG polymeric microfibers as dressings for administering the antibiotic gentamicin directed at skin infections. PHB-PEG/gentamicin fibers were characterized before and after plasma treatment by Raman spectroscopy, FTIR, and XRD. SEM was used to evaluate fiber morphology and yarn size. The plasma treatment improved the hydrophilicity of the PHB/PEG/gentamicin fibers. The release of gentamicin in the plasma-treated fibers was more sustained over time than in the untreated ones.

Wind turbine blades are made from fiberglass, whose faces are eroded due to environmental conditions. Polyurethane (PU) coatings are broadly used in several types of coatings due to their strong adhesion. However, their inferior mechanical properties limit their application on fiberglass. In this study, graphene oxide (GO) was modified through a dielectric barrier plasma (DBP) treatment at atmospheric pressure to improve the dispersion of GO in PU and increase its adhesion to fiberglass (GF) substrates, resulting in excellent adhesion properties of the PU/GO coating on fiberglass. Additionally, PU/GO coatings are crucial for preventing and protecting against erosion. The results obtained for the intensity ratio of the $I_D/I_G$ peaks observed through Raman spectroscopy exhibited that the plasma treatment increased the defects in the GO structure through covalent and non-covalent interactions with the PU. Contact angle tests and surface free energy measurements indicated the deoxygenation of the GO structure, enhancing its dispersion in the PU matrix, as observed through XRD. The plasma treatment increased the PU/GO adhesion by 27.6% after 10 min of treatment, suggesting that more defects in the GO structure were correlated with greater adhesion strength.