Poly(lactic acid) (PLA) is a versatile, bioabsorbable, and biodegradable polymer with excellent biocompatibility and ability to incorporate a great variety of active agents. Silver sulfadiazine (SDZ) is an antibiotic used to control bacterial infection in external wounds. Aiming to combine the properties of PLA and SDZ, hydrotalcite ([Mg-Al]-LDH) was used as a host matrix to obtain an antimicrobial system efficient in delivering SDZ from electrospun PLA scaffolds intended for wound skin healing. The structural reconstruction method was successfully applied to intercalate silver sulfadiazine in the [Mg-Al]-LDH, as evidenced by X-ray diffraction and thermogravimetric analyses. Observations by scanning electron microscopy revealed a good distribution of SDZ-[Mg-Al]-LDH within the PLA scaffold. Kinetics studies revealed a slow release of SDZ from the PLA scaffold due to the intercalation in the [Mg-Al]-LDH. In vitro antimicrobial tests indicated a significant inhibitory effect of SDZ-[Mg-Al]-LDH against Escherichia coli and Staphylococcus aureus. This antibacterial activity was sustained in the 2.5-wt% SDZ-[Mg-Al]-LDH-loaded PLA nanofibers, which also displayed excellent biocompatibility towards human cells. The multifunctionality of the PLA/SDZ-[Mg-Al]-LDH scaffold reported here is of great significance for various transdermal applications. K E Y W O R D S drug release, electrospinning, hydrotalcite, sulfadiazine silver, wound healing

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Hydroxyapatite (HA) is an inorganic material with high ability to interact with proteins and has been recently explored as a support for enzyme immobilization. However, there are still some drawbacks concerning the recovery of these biocatalysts, which could be overcome using magnetic supports. Cobalt ferrite (CoFe 2 O 4 ) is a purely magnetic material, which offers excellent chemical stability, ease of synthesis, and mechanical hardness, being a promising candidate to form composites with HA and produce magnetic HA nanoparticles. Therefore, investigation of synthesis procedures and applications of HA/CoFe 2 O 4 composites to facilitate enzyme recovery by means of a magnetic field could find interest in a broad spectrum of biotechnological processes. Here, the co-precipitation method was used to synthesize HA/CoFe 2 O 4 composites with different HA/CoFe 2 O 4 mass ratios, for application as supports for enzyme immobilization. The enzymes β-glucosidase, phytase, and xylanase were selected for proof of concept due to their wide range of industrial applications. The composite with the highest cobalt ferrite content (2:1 mass ratio) was highly effective for immobilization of the three different enzymes, with immobilization yields (IYs) of 70−100% and recovered activities of 78−100%. The biocatalysts could be easily recovered from the reaction media by both centrifugation and application of an external magnetic field, demonstrating their potential for use in industrial processes. The materials exhibited good reusability, especially in the case of the βglucosidase biocatalyst, which could be reused 10 times, maintaining around 70% of its initial activity.

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Copper oxide (CuO) has been broadly used in different technological and biological applications. However, based on the literature review, there are few reports describing the synthesis of tungsten doped copper oxide and its biological applications, although CuO and W (tungsten) based nanomaterials have been reportedly already synthesized. In this study we synthesized novel CuO and CuO/W (at.1%, 2% and 4%) nanoparticles and explored their tungsten content-dependent bactericide activity. In order to obtain the materials, was used a co-precipitation method which is of low cost. The synthesized materials were characterized by x-ray diffraction (XRD); XRD results indicated that only the sample with at.1% of W presented pure Tenorite phase. Diffuse reflectance spectroscopy (DRS) allowed to obtain the band gap energy values; CuO/W (at.2%) sample exhibited the minimum value of 2.62 eV. Grains sizes ranging from 39.78 to 53.47 nm were established through field emissionscanning electronic microscopy (FE-SEM), and these sizes were confirmed by transmission electron microscopy (TEM). Doping with W also influenced the morphology obtained in all cases. BET (Brunauer, Emmett, Teller) analysis allowed to establish an increase in specific surface area and pore size with W doping. The particle size was determined by dynamic light scattering (DLS). The bactericidal properties were tested using well diffusion method for Escherichia coli and Staphylococcus aureus bacteria. Bactericide response of CuO nanoparticles was improved by the inclusion of W dopant into the CuO structure, leading to an expansion in the inhibition zone for the CuO/W (at.1%) sample; inhibition halo diameters were 1.5 and 12 mm for CuO and CuO/W (at.1%), respectively. Hence, it was possible to

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α-Fe2O3 samples were manufactured by means of the polymeric precursor method. The powders were sintered and calcined at temperatures of 300–700 °C for 2 h, respectively. In the X-ray diffraction results, the formation of the rhombohedral phase without secondary phases was exhibited. The size of the particle increased after calcination at 700 °C, exhibiting a slightly more irregular morphology for the samples calcined with the addition of NH4OH in the synthesis process. From the field-emission scanning electron microscopy measurements, the particle size was determined, showing a smaller size for the samples without NH4OH in the synthesis process. The samples calcined at 600 °C had a size of 100 nm, with the sizes for lower temperatures being smaller. The size of the nanoparticle agglomerates was largest for the samples with NH4OH; however, the zeta potential was slightly lower over time for these samples. The phase study of the α-Fe2O3 nanoparticles was confirmed by means of Raman spectroscopy, without additional bands of another crystal structure. In addition, the synthesized nanoparticles exhibited good photocatalytic activity in the degradation of rhodamine B (RhB) and atrazine (ATZ) within 40 min, with a maximum degradation of 59% for ATZ and 40% for rhodamine. The best responses in the degradation were for the samples without the addition of NH4OH in the synthesis process and in proportions lower than 0.1 g. The cytotoxic effects of the nanoparticles obtained at 600 °C were evaluated in apical cells of onion roots. The results are promising for future applications because no changes were observed in the mitosis of the cells.