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.