Percorrer por autor "Barroso, H."
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- Antimicrobial casein/poly(vinyl alcohol) electrospun nanofibers-based dressingsPublication . Nobre, D.; Ekoh, E.; Silva, D. C.; Branco, A. C.; Pais, V.; Almeida, A.; Barroso, H.; Salema-Oom, M.; Fangueiro, R.; Colaço, R.; Galante, R.; Serro, A. P.Diabetes affects millions globally, with a rising prevalence. Chronic wounds are one of its major complications, due to the healing difficulty, highlighting the need for innovative solutions to improve the treatments efficacy. Electrospun nanofiber dressings show promising due to their ECM-like structure, oxygen permeability, and potential for bioactive functionalization. In this study, casein/poly(vinyl alcohol) (CAS/PVA) nanofibers were electrospun with antimicrobial compounds: Octiset®, polyhexanide, and ZnO particles. After crosslinking with glutaraldehyde (GA), the nanofibers mats were characterized regarding their morphology, swelling capacity, enzymatic degradation, drug release behavior, cytotoxicity, hemocompatibility, irritability potential and antimicrobial potential. They demonstrated notable swelling capacity, and therefore potential to absorb exudate and maintain a moist healing environment in the wound. Those containing polyhexanide and Octiset® (CAS/PVA_Poli and CAS/PVA_Octi) showed a significant drug release for over 4–8 h, that prolonged at a slower rate for 24 h, being mainly diffusion-controlled. The crosslinker reduced the amount of drug released and the degradation of the nanofibers but increased their water absorption capacity. CAS/PVA_Poli and CAS/PVA_Octi exhibited the most interesting set of results, as besides being non-cytotoxicity, hemocompatible and non-irritant, presented excellent antimicrobial efficacy and superior performance when compared with the crosslinked samples. They were effective against Staphylococcus aureus, Escherichia coli, and Candida albicans, and in particular against Methicillin Resistant Staphylococcus aureus and Streptococcus pyogenes which are a dangerous threat in diabetic wounds. Overall, their morphological similarity with the extracellular matrix and excellent biological properties, turns them good candidates to be used in dressings for the treatment of diabetic wounds.
- Open air children playgrounds: the importance of microbial control of floorPublication . Matias, C.; Fernandes, A.; Proença, L.; Duarte, A.; Barroso, H.
- The corrosion resistance of Wiron88 in the presence of S. mutans and S. sobrinus bacteriaPublication . Proença, L.; Barroso, H.; Figueiredo, N.; Lino, A. R.; Capelo, S.; Fonseca, I. T. E."The corrosion resistance of Wiron®88, a Ni–Cr–Mo alloy, was evaluated in liquid growth media in the absence and presence of the Streptococcussobrinus and Streptococcus mutans strains. Open circuit potential measurements, cyclic voltammetry, linear sweep voltammetry, as well as electronic microscopy coupled to electron diffraction spectroscopy (SEM/EDS), were the main techniques used in this study. It was concluded that the presence of S. sobrinus and S. mutans have only a slight effect on the corrosion resistance of the Wiron®88 alloy, with the S. mutans being slightly more aggressive. For both strains the corrosion resistance Rp is of the same order (kΩ cm2). After 24 h immersion the S. sobrinus lead to and Rp of 11.02, while the S. mutans lead to of 5.59 kΩ cm2. SEM/EDS studies on the Wiron®88 samples, with 24 days of immersion, at 37 °C, have confirmed bio-corrosion of the alloy occurring through the dissolution of Ni as Ni2+ and formation of chromium and molybdenum oxides. The bacterial adhesion to the surface is not uniform."