Browsing by Author "Rojas, Orlando J."
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- Bio-based composite materials from olive stonePublication . Sibaja, María; Alvarado, P.; Jiménez, L.; Rojas, Orlando J.; Barreiro, M.F.; Cateto, Carolina; Rodrigues, Alírio; Lopretti, MaryThe present work describes the methodology used for the preparation and characterization of composite samples prepared by mixing various percentages of olive stone flour in a polyester resin matrix. A study on the chemical-physical properties of the olive stone is reported, as well as, a set of tests to evaluate the mechanical properties of the manufactured products obtained. Biodegradation studies were carried out on the obtained composite materials.
- Bio-based composite materials from olive stonePublication . Sibaja, María; Alvarado, P.; Jiménez, L.; Rojas, Orlando J.; Barreiro, M.F.; Cateto, Carolina; Rodrigues, Alírio; Lopretti, MaryThe present work describes the methodology used for the preparation and characterization of composite samples prepared by mixing various percentages of olive stone flour in a polyester resin matrix. A study on the chemical-physical properties of the olive stone is reported, as well as, a set of tests to evaluate the mechanical properties of the manufactured products obtained. Biodegradation studies were carried out on the obtained composite materials.
- 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.