Lindoval Serrano da Fonseca

Complex wounds represent a significant clinical challenge, requiring advanced wound dressings capable of combining mechanical stability, moisture control, and bioactivity. In this study, hybrid polyurethane (PU) and O ‐carboxymethyl chitosan (OCMCh) composites were developed through surface chemical modification to enhance multifunctional performance. The interaction between PU and OCMCh was carefully investigated, indicating the formation of covalent amide bonds associated with protonation and deprotonation mechanisms. The composites were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), optical microscopy (OM), scanning electron microscopy (SEM), contact angle measurements to evaluate surface wettability, and mechanical testing to assess their mechanical performance. In addition, their antimicrobial activity and cytocompatibility were evaluated to determine their biological performance and suitability for wound dressing applications. The incorporation of OCMCh significantly increased hydrophilicity and water absorption capacity under optimized conditions (24 h, 40°C, pH ~7.4), maintaining thermal stability adequate for biomedical profile. Morphological analysis revealed a homogeneous and porous structure, which is favorable for exudate management and cell interaction. Compared to conventional commercial dressings such as Tegaderm and Allevyn, the composites exhibited improved wettability and enhanced fluid absorption capacity, indicating superior performance in maintaining a moist wound environment. Furthermore, the combination of synthetic and natural polymers contributes to improved functional properties and expands the potential applications of these materials in biomedical fields. These results suggest that PU/OCMCh composites are promising candidates for next‐generation wound dressings.

The global demand for food has been increasing, presenting new challenges in meeting this demand. To address this growing need, the use of coating technology through nanoemulsions shows great potential. The use of thyme essential oil stabilized by chitosan nanoparticles offers a promising and sustainable approach for the development of edible coatings. Chitosan was extracted from shrimp shell waste and used to produce nanoparticles via the ionotropic gelation method, using sodium tripolyphosphate (TPP) as a crosslinking agent. To prepare the nanoemulsions, thyme essential oil was used as the dispersed phase, combined with an aqueous phase containing chitosan nanoparticles and Tween 80 as the emulsifier. Two techniques were employed to produce nanoemulsions: high-pressure homogenization and ultrasonication. Nanoemulsion formulations with different concentrations were prepared and characterized in terms of droplet size (Z-Average) and stability using dynamic light scattering (DLS). The average droplet sizes obtained were above 100 nanometers for samples produced via high-pressure homogenization and below 100 nanometers for those prepared using ultrasonication. Analysis of variance (ANOVA) confirmed that both the method (p = 0.002) and the oil phase concentration (p < 0.001) had statistically significant effects on droplet size. Regression analysis showed that oil concentrations below 2.0 g (w/w) increased droplet size, while concentrations above 4.0 g (w/w) significantly reduced it (p < 0.05). However, physical stability tests conducted at 5 °C for 30 days showed consistent values across both formulations, with only minor fluctuations, suggesting overall good stability.

Premature birth accounts for nearly half of perinatal deaths worldwide, making its prevention a major public health priority. Although vaginal administration of natural progesterone is an effective prophylactic strategy, its daily use is often associated with irritation and low patient adherence. In this context, biodegradable, biocompatible, and mucoadhesive polymers such as chitosan and gelatin emerge as promising materials for controlled drug delivery systems. This study aimed to develop and characterize progesterone-loaded ovules based on chitosan and gelatin for the prevention of premature birth. The formulations were produced by lyophilization and evaluated in terms of morphology, chemical structure, thermal stability, swelling behavior, biodegradation, and cytotoxicity. Fourier transform infrared spectroscopy (FTIR) analysis indicated successful incorporation of progesterone into the polymeric matrix. Swelling and biodegradation assays provided insight into the degradation profile of the system, suggesting that the matrix may support modulated progesterone diffusion. Thermal analysis (TGA) showed that pure chitosan presented greater thermal stability, while the addition of gelatin and progesterone slightly reduced this property. Cytotoxicity results confirmed the biocompatibility of the developed formulations. Overall, the findings suggest that these ovules are a promising platform for progesterone delivery and may contribute to innovative biomaterial-based approaches for the prevention of preterm birth.

Varicose ulcers represent a severe manifestation of chronic venous insufficiency and remain a major public health challenge. In this study, chitosan-based dressings incorporating Jatropha mollissima extract (1-5% m/m) were developed via lyophilization to enhance healing performance. The membranes exhibited a predominantly fibrous morphology with high swelling capacity, approximately 1600% for pure chitosan, with a progressive reduction upon extract incorporation, indicating a decrease in hydrophilicity and increase in network density. Fourier transform infrared spectroscopy (FTIR) analysis revealed intensified bands associated with O–H and N–H groups, suggesting hydrogen bonding interactions between chitosan and phenolic compounds of the extract. Thermogravimetric analysis showed improved thermal stability, with reduced mass loss in extract-loaded membranes (ca. 50-60%) compared to pure chitosan. Biodegradation assays demonstrated a decrease in mass loss from 73.43 (M) to 65.00% (MJ5) after 21 days in phosphate salt (PBS), indicating enhanced structural stability. All samples exhibited no cytotoxicity toward L929 fibroblasts. These results demonstrate that the incorporation of J. mollissima modulates physicochemical properties through intermolecular interactions, leading to reduced swelling, controlled degradation, and improved stability. The study highlights the novelty of combining chitosan with a Caatinga-derived bioactive extract to produce multifunctional membranes with tunable physicochemical and biological properties, although further studies are required to confirm their suitability for biomedical applications.

Maçaranduba is a fruit native to Northeast Brazil, yet it remains relatively unknown due to its short shelf life, which limits its commercialization and distribution to distant markets. Extending the fruit’s longevity through sustainable preservation methods, such as edible coatings, can enhance its market potential. Meanwhile, shrimp farming is a significant economic activity in the Brazilian Northeast, generating large amounts of waste that, if not correctly managed, contribute to environmental pollution. One sustainable approach to mitigate this issue is the extraction of chitosan, a biopolymer derived from shrimp residues, which has demonstrated the potential to extend the shelf life of perishable fruits. This study is aimed at optimizing chitosan extraction from shrimp residues and evaluating its effectiveness as a coating for Maçaranduba fruits. The extraction process was optimized using response surface methodology (RSM) combined with the normal boundary intersection (NBI) approach, specifically focusing on enhancing yield and purity. The obtained chitosan, with a yield of 3.637 g/100 g and a purity of 84.584%, was then applied as a coating to Maçaranduba fruits, and its effects on shelf life were assessed through physicochemical analyses. The results demonstrated that the chitosan coating significantly improved key quality parameters, including reduced water activity, pH stabilization, lower mass loss, and decreased soluble solids variation. These findings highlight the potential of shrimp‐derived chitosan as an eco‐friendly and effective solution for fruit preservation. Furthermore, promoting the sustainable utilization of shrimp waste aligns with circular economy principles, reducing environmental impact while adding value to the aquaculture and agricultural sectors.