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Percorrer por autor "Cenci, Giovana Baptista"

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  • From experimental implementation to validation of natural-based electrospun solutions
    Publication . Cenci, Giovana Baptista; Echart, Arantzazu Santamaria; Barreiro, M.F.; Dusman, Elisângela
    Electrospinning is a straightforward and versatile technology for producing fibers with diameters ranging from a few micrometers to hundredths of nanometers. It applies a strong electric field to charge a polymer solution contained within a syringe. This study focused on the assembly, implementation, and validation of an electrospinning equipment. Also, it was validated by testing a conventional synthetic polymer, polyethylene-oxide (PEO). Finally, mats using chitosan (CS) and hyaluronic acid (HA) as natural polymers were prepared with PEO used as a co-spinner. Solutions comprising various proportions of PEO/CS (40/60, 50/50, 60/40, and 70/30) and PEO/CS/HA (HA 0.1, 0.2, and 0.3%) exhibited the highest conductivity values (between 1306 and 1885 μS/cm) using acetic acid (AA) (50% w/w). The electrospun mats from these blends displayed superior uniformity compared to other films, with mean diameters ranging from 0.204 ± 0.046 μm to 0.282 ± 0.064 μm. Increasing the applied voltage in neat PEO solutions led to a decrease in fiber diameter from 0.540 ± 0.172 μm (10 kV film) to 0.362 ± 0.130 μm (16 kV film). However, all neat PEO electrospun mats showed beads and non-uniformities, mainly due to the presence of distilled water (DW) as a solvent. DW also increased viscosity and reduced conductivity in PEO/HA blends compared to AA equivalents. PEO/HA (DW) solutions formed films of particles instead of fibers. PEO/HA (AA) mats exhibited average fiber diameters ranging from 0.311 ± 0.071 μm to 0.381 ± 0.094 μm, with lower levels of uniformity. All produced mats exhibited a high hydrophilicity, with PEO/CS mats demonstrating the highest contact angle (31° after 60 seconds; PEO/CS_30/70_AA). The addition of HA in PEO/CS_50/50_AA increased hydrophilicity. Interestingly, in the PEO/CS/HA mats, higher HA concentrations led to increased contact angles (18.10°, 22.50°, and 24.57° for 0.1%, 0.2%, and 0.3% HA, respectively), suggesting the formation of polyelectrolyte complexes between NH3+ (CS) and COO− (HA). The MTT assay results show no cytotoxicity in the PEO/CS and PEO/CS/HA electrospun mats. Cell viability for groups exposed to these mats exceeded 74.23%, highlighting the inherent biocompatibility of CS and HA. Overall, this study underscores the potential of CS and HA nanofibers for biomedical applications, alongside the successful implementation of the equipment.
    2024Dissertação de mestrado Acesso restrito Ver mais