3D bioprinting has gained visibility in regenerative medicine and tissue engineering due to its applicability. Over time, this technology has been optimized and adapted to ensure a better printability of bioinks and biomaterial inks, contributing to developing structures that mimic human anatomy. Therefore, cross-linked polymeric materials, such as hydrogels, have been highly targeted for the elaboration of bioinks, as they guarantee cell proliferation and adhesion. Thus, this short review offers a brief evolution of the 3D bioprinting technology and elucidates the main hydrogels used in the process.

The interaction of copaiba oil in the polymer matrix of chitosan can produce a favorable synergistic effect and potentiate properties. Indeed, the bioactive principles present in copaiba oil have anti-inflammatory and healing action. In the present work, chitosan membranes containing different contents of copaiba oil copaíba (0.1, 0.5, 1.0 and 5.0% (v/v)) were for the first time investigated. The membranes were developed by the casting method and analyzed for their morphology, degree of intumescence, moisture content, contact angle, Scanning Electron Microscope, and X-ray diffractometry. These chitosan/copaiba oil porous membranes disclosed fluid absorption capacity, hydrophilic surface, and moisture. In addition, the results showed that chitosan membranes with the addition of 1.0% (v/v) of copaiba oil presented oil drops with larger diameters, around 123.78 μm. The highest fluid absorption indexes were observed in chitosan membranes containing 0.1 and 0.5% (v/v) of copaiba oil. In addition, the copaiba oil modified the crystalline structure of chitosan. Such characteristics are expected to favor wound treatment. However, biological studies are necessary for the safe use of chitosan/copaiba oil membrane as a biomaterial.

Chitosan comprises polymeric macromolecules with technical and biological properties that have been used in biomedical healing applications requiring anti-microbial and anti-inflammatory capacities worldwide. In the tropical regions, green banana peel extract and andiroba oil are considered natural products with wound healing properties. The present study, for the first time, synthesized chitosan/green banana peel extract/andiroba oil (CGA) membranes and analyzed them using scanning electron microscopy (SEM) and the swelling and moisture tests. The CGA membranes together with control membranes of plain chitosan and chitosan plus green banana peel extract, were characterized by contact angle measurement, X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Macroscopic analysis showed significant differences in color and transparency caused by the number of decoction days used for extract preparation and the oil content. SEM observations disclosed the formation of two phases, lipid and polymer, in the CGA. The number of decoction days and the andiroba oil content were inversely related to the swelling moisture uptake. All membranes were found to be hydrophilic with contact angles less than 90°. The incorporation of plant extract and oil promoted the appearance of related XRD peaks. DSC curves revealed a reduction in the enthalpy of the CGA membranes compared with plain chitosan, which might be attributed to the evaporation of the natural extract and oil. Based on these findings, the studied newly synthesized membranes demonstrated a potential for healing epithelial lesions.

Tissue engineering is vital in treating injuries and restoring damaged tissues, aiming to accelerate regeneration and optimize the complex healing process. In this study, multizonal scaffolds, designed to mimic tissues with bilayer architecture, were prepared using the rotary jet spinning technique (RJS scaffolds). Polycaprolactone and different concentrations of alginate hydrogel (2, 4, and 6% m/v) were used. The materials were swollen in pracaxi vegetable oil (PO) (Pentaclethra macroloba) and evaluated in terms of surface morphology, wettability, functional groups, thermal behavior, crystallinity, and cytotoxicity. X-ray diffraction (XRD) showed the disappearance of the diffraction peak 2θ = 31.5° for samples from the polycaprolactone/pracaxi/alginate (PCLOA) group, suggesting a reduction of crystallinity according to the presence of PO and semi-crystalline structure. Wettability gradients (0 to 80.91°) were observed according to the deposition layer and hydrogel content. Pore diameters varied between 9.27 μm and 37.57 μm. Molecular interactions with the constituents of the formulation were observed via infrared spectra with Fourier transform (FTIR), and their influence was detected in the reduction of the maximum degradation temperature within the groups of scaffolds (polycaprolactone/alginate (PCLA) and PCLOA) about the control. In vitro tests indicated reduced cell viability in the presence of alginate hydrogel and PO, respectively.

Publicado em 21 de novembro de 2022. O e-book: “Engenharia química: Desenvolvimento de novos processos e produtos 3” é constituído por quatro capítulos de livro que investigaram: i) propriedade de óleos vegetais para a síntese de biopolímeros; ii) reaproveitamento de casca de noz-pecã no processo de imobilização de peroxidase de raíz forte; iii) biotransformação do fungo Aspergillus flavus frente as chalconas sintéticas e acetofenona e; iv) utilização do catalisador 1%Cu/5%Ni/Nb2O5-12%CeO2 empregado no processo de reforma do etanol sob vapor d’água na geração de gás hidrogênio como fonte de energia. O primeiro capítulo avaliou a influência do grau de insaturação de óleos vegetais na obtenção de biopolímeros sintetizados a partir de frutos típicos da região amazônica: Açaí, Jupati, Compadre de azeite, Patauá, Castanha-do-Pará e Pracaxi. As amostras dos diferentes óleos foram caracterizadas utilizando-se a técnica de Cromatografia Gasosa e posterior determinação do índice de iodo, obtendo-se o maior e o menor índice, respectivamente para o óleo de compadre de azeite e pracaxi, sendo que este último resultou apenas em resinas de alta viscosidade. O capítulo 2 investigou a capacidade d reaproveitar resíduos provenientes da casca de noz-pecã como imobilizador de peroxidase de raiz forte utilizando a adsorção e ligação covalente como metodologia, sendo obtida uma recuperação de atividade de 124,8% e 129,7%, respectivamente, indicando que partículas de menor granulometria possuem maior capacidade de imobilização. O capítulo 3 avaliou a potencialidade de biotransformação do fungo Aspergillus flavus frente às chalconas sintéticas e acetofenona.Os resultados confirmaram que o micro-organismo apresentou elevada capacidade de biorredução da dupla ligação α, β-carbonilada das chalconas existentes em seis diferentes formulações que foram confirmadas por meio dos espectros de RMN 1H e a capacidade do fungo de modificar o substrato acetofenona, indicando elevada eficiência nas reações de biotransformação. Por fim, o quarto capítulo investigou a eficiência do catalisador composto por 1%Cu/5%Ni/Nb2O5-12%CeO2 no processo de reforma do etanol com vapor d’água. Os resultados demonstraram que a taxa de conversão em gás hidrogênio foi de 40%, com produção de coque em torno de 3%. Logo, o uso do catalisador proporcionou a geração de um combustível (gás hidrogênio) que contribui para a consolidação de uma nova matriz energética que vem ganhando cada vez mais espaço em função de possibilitar não somente em uma fonte renovável de energia, mas contribui para reduzir a emissão de gases que afetam o equilíbrio do meio ambiente. Nesta perspectiva, a Atena Editora vem trabalhando de forma a estimular e incentivar cada vez mais pesquisadores do Brasil e de outros países a publicarem seus trabalhos com garantia de qualidade e excelência em forma de livros, capítulos de livros e artigos científicos. Prof. Dr. Cleiseano Emanuel da Silva Paniagua

The rapid expansion of the global açaí (Euterpe oleracea) market has led to an alarming increase in waste generation, particularly seeds and fibers, posing significant environmental challenges. This review explores innovative strategies to repurpose these residues through cutting-edge technologies, including nanotechnology for nanocellulose production, microbial fermentation for biopolymer synthesis, and green extraction methods for obtaining bioactive compounds. Emphasis is placed on the development of high-value-added products such as biodegradable plastics, biomaterials, and renewable energy sources, aligning with the principles of the circular economy. Additionally, the review highlights the socioeconomic potential of these innovations and their role in mitigating environmental impacts. A focus is given to the need for sustainable practices and policy-driven initiatives to maximize the value of açaí residues, calling for solutions to overcome technological and economic barriers while promoting sustainable development in the Amazon region. Graphical Abstract The figure illustrates the various applications of açaí within the concept of circular economy, highlighting how different parts of the fruit and its waste can be used sustainably. In the center, açaí is presented as the main raw material, with ramifications for five sectors: cosmetics, biofertilizers, nutraceuticals, biopolymers and biofuels. In the cosmetics area, bioactive compounds are used in skin and hair products. Organic waste is used in the production of biofertilizers, while nutraceuticals take advantage of the fruit's natural antioxidants. Biopolymers are obtained from lignocellulosic waste, with a focus on biodegradable materials. Biofuels use oils and biomass to generate renewable energy. The proposal aims to reduce waste, add value to byproducts and strengthen the sustainability of the açaí production chain