Percorrer por autor "Muazeia, Jeremias"
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- Hydrogel dressings loaded with anticancer/antimicrobial Ag(I) camphorimine complexes for treatment of malignant woundsPublication . Costa, Joana P.; Silva, Diana C.; Marques, Fernanda; Muazeia, Jeremias; Leitão, Jorge H.; Pinto, Carlos A.; Saraiva, Jorge A.; Serro, Ana P.; Carvalho, M. Fernanda N. N.The treatment of skin wounds caused by metastatic lesions is often difficult because not many medicines exist that simultaneously act on cancer cells and bacteria. Such difficulty delays and sometimes compromises the treatment of oncologic patients. To contribute to face that problem a set of silver camphorimine compounds with antibacterial properties were assessed for activity against cancer cells A375 and MeWo melanoma cells using the MTT assay. From them, the silver camphorimine complex 1 displayed the highest combined anticancer and antibacterial activities and therefore was incorporated in a HEMA-based hydrogel to be used in a wound dressing. The hydrogel disks loaded with complex 1 effectively reduced suspensions of E. coli, P. aeruginosa and B. contaminans from the initial 5 × 105 CFU/mL to 0 CFU/mL after 24 and 48 h of incubation. In the case of S. aureus, a reduction of more than 99 % was observed after 24 h. However, after 48 h of incubation, the hydrogel was ineffective towards S. aureus. Although presenting a non-porous structure, the hydrogel revealed to be hydrophilic and able to retain a significant water content, allowing to keep the wound moist. Additionally, it exhibited mechanical and mucoadhesive properties suitable for treatments involving repeated and frequent dressing changes. The hydrogels were loaded with complex 1 by soaking and then sterilized by high hydrostatic pressure (HHP). Biocompatibility studies demonstrated that the loaded dressings were non-irritant and hemocompatible. The sterilization procedure did not affect the integrity of the complex, nor the drug release, which occurred in a sustained way through a non-Fickian diffusion mechanism. The dressing released 618.5 mg/cm2/24 h, with nearly 90 % of the release occurring within the first 8 h. Considering the exudate production rates of chronic wounds and the MIC and MBC values for complex 1 it is expected that the dressings will be effective as antibacterial and anticancer agents. In vivo studies will be needed to confirm the clinical potential of the dressings. However, the produced dressings offer a promising approach for both infection control and cancer therapy in chronic wounds.
- Tuning anticancer activity and antimicrobial response of ZnO nanoparticles through halogenosilane surface modificationPublication . Bușilă, Mariana; Tăbăcaru, Aurel; Botezatu, Andreea Veronica; Ceoromila, Alina-Mihaela; Moroșanu, Ana-Maria; Muazeia, Jeremias; Leitão, Jorge Humberto Gomes; Matos, António Pedro; Marques, FernandaSurface modification of zinc oxide nanoparticles (ZnO NPs) with organosilane capping agents represents an effective strategy to control their physicochemical and biological properties. In this work, we report for the first time the use of halogenosilanes, namely (3-chloropropyl)trimethoxysilane (CPTMS), (3-bromopropyl)trimethoxysilane (BPTMS) and (3-iodopropyl)trimethoxysilane (IPTMS), for the surface functionalization of ZnO NPs obtained by chemical precipitation. Structural and morphological characterization (PXRD, TEM, SEM-EDX and FTIR) confirmed successful surface modification and revealed a significant particle size reduction from ~31 nm for unmodified ZnO to ~8 nm for BPTMS-modified ZnO (ZnO_b). The biological evaluation showed that halogenosilane-modified ZnO NPs exhibit enhanced cytotoxic activity against prostate cancer cell lines (PC3 and 22Rv1), with ZnO_b displaying the highest activity, likely associated with improved cellular uptake and increased reactive oxygen species (ROS) generation. In contrast, antimicrobial assays revealed only moderate bactericidal effects against Escherichia coli and Staphylococcus aureus at relatively high concentrations (≥1250 µg mL−1), while no significant activity was observed against Pseudomonas aeruginosa, Burkholderia contaminans or Candida spp., within the tested range. These findings suggest that halogenosilane functionalization modulates the biological profile of ZnO nanoparticles by enhancing anticancer effects while also influencing microbiocidal activity, highlighting the role of surface chemistry in tuning biological selectivity. The present study supports the concept that rational surface engineering of ZnO-based nanoplatforms can be exploited to favor tumor-targeted activity over broad-spectrum antimicrobial effects, providing new perspectives for the design of application-oriented nanomaterials.