Browsing by Author "Fangueiro, Raul"
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- Chitosan/nanocellulose electrospun fibers with enhanced antibacterial and antifungal activity for wound dressing applicationsPublication . Ribeiro, Ana S.; Costa, Sofia M.; Ferreira, Diana P.; Calhelha, Ricardo C.; Barros, Lillian; Stojković, Dejan; Soković, Marina; Ferreira, Isabel C.F.R.; Fangueiro, RaulThe combination of biodegradable fibers at nanoscale with plant-based extracts is attracting increasing attention to produce wound dressing systems. In this work, nanofibers based on chitosan (CS), poly(ethylene oxide) (PEO), cellulose nanocrystals (CNC) and acacia plant-based extract were developed by electrospinning. Firstly, the polymeric formulations and electrospinning parameters were optimized, resulting in nanofibers with average diameters of 80 nm. CNC were successfully introduced into the optimized CS/PEO blend and the membranes were characterized by FESEM, ATR-FTIR, TGA, XRD, WVTR and WCA. The CNC incorporation improved the nanofibers' physical integrity, morphology, diameters, water vapor transmission rate and thermal properties. After acacia introduction into the best CS/PEO/CNC system, the antibacterial effect was relatively maintained while the antifungal activity was enhanced for some fungi, demonstrating its great effect against a wide range of microorganisms, which is crucial to prevent or treat infections. All the developed systems exhibited absence of cytotoxicity in non-tumor cells, suggesting their biocompatibility. Finally, a continuous release of the acacia extract was observed for 24 h, showing its prolonged action, which contributes to the healing process while reduces the frequency of dressing's replacement. Overall, the developed nanofibers are very promising to act as localized drug delivery systems for wound care applications.
- Electrospun polycaprolactone membranes functionalized with nanochitin for enhanced bioactivity in localized cancer photodynamic therapyPublication . Costa, Sofia M.; Mattos, Bruno D.; Calhelha, Ricardo C.; Zhu, Ya; Lima, Eurico; Reis, Lucinda; Rojas, Orlando J.; Fangueiro, Raul; Ferreira, Diana P.The encapsulation of photosensitizers (PSs) in electrospun membranes has emerged as a promising approach in photodynamic therapy (PDT) on tumor sites, overcoming the drawbacks associated with systemic administration. In this work, localized implants for cancer treatment using PDT were developed by incorporating EL-2 squaraine into poly(epsilon-caprolactone) (PCL) electrospun microfibers. The latter were coated with chitin nanocrystals (ChNC) by electrospraying, which may improve the biocompatibility and bioactivity of the developed membranes, potentially enhancing the clinical outcomes. The developed electrospun membranes were characterized by water contact angle, imaging, and spectroscopy techniques. The uniform encapsulation and distribution of EL-2 within the microfibers were confirmed while ChNC endowed the membranes with surface hydrophilicity. EL-2 alone displayed about 20 times more cytotoxicity after irradiation compared to the dark condition against HeLa cervical carcinoma cells. Meanwhile, the photodynamic action of PCL+EL-2/ChNC membranes promoted a significant inhibition of cancer cells' proliferation under irradiation, achieving 66.25 % of inhibition, compared to only 24.78 % in dark conditions, using the highest concentration of EL-2. Overall, this work introduces a disruptive strategy using electrospinning-electrospraying to design fibrous therapeutic platforms for cancer PDT, taking advantage of electrospun fibers unique features and the localized nature of photodynamic therapy.
- Localized cancer photodynamic therapy approach based on core–shell electrospun nanofibersPublication . Costa, Sofia M.; Lourenço, Leandro M.O.; Calhelha, Ricardo C.; Calejo, Isabel; Barrias, Cristina C.; Fangueiro, Raul; Ferreira, Diana P.Photodynamic therapy (PDT) has been considered a promising treatment for several types of cancer, including cervical cancer. Localized drug delivery systems (DDSs) based on nanofibers produced by electrospinning have emerged as a powerful platform to carry and deliver photosensitizers (PSs) onto or adjacent to the tumor site, thereby promoting higher therapeutic efficacy and reducing the side effects to healthy tissues associated with systemic administration. In this work, core–shell electrospun nanofibers were produced using biodegradable polymers, such as poly(vinyl alcohol) (PVA) and gelatin (Gel), to act as a localized DDS for the treatment of cervical cancer using PDT. The synthesized porphyrin (Por) was able to generate singlet oxygen (FD = 0.62) and displayed higher phototoxicity against tumor cells compared with healthy cells. The developed PVA–Gel membranes were fully characterized, revealing defect-free nanofibers with a core–shell structure. Different Por concentrations were added to the fibers’ core, and their presence and uniform distribution within the nanofibers were confirmed. The Por release profile from nanofibers showed an initial fast release stage, followed by continuous release for at least 9 days. The PVA–Gel + Por core–shell nanofibers exhibited a higher inhibition of cancer cell proliferation under light irradiation when compared to dark and a higher phototoxic effect against tumor cells compared with non-tumor cells. Overall, this study demonstrates the great potential of core–shell nanofibers to be used as localized DDSs of PSs for the treatment of cervical cancer.