Browsing by Author "Calvinho, Paula Cristina Nunes Ferreira"
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- Beeswax-enriched tricalcium phosphate/hydroxyapatite/sodium alginate/ thymol 3D-printed scaffolds for application in bone tissue engineeringPublication . Francisco, Martinho Jorge ; Cabral, Cátia Solange Duarte; Calvinho, Paula Cristina Nunes Ferreira ; Correia, Ilídio Joaquim Sobreira ; Moreira, André FerreiraTissue engineering, particularly bone tissue engineering (BTE), continues to pose significant challenges to modern medicine. In this work, a rapid prototyping technique was explored to create 3D scaffolds using a Fab@Home 3D-Plotter extruder. For that purpose, a novel composite mixture containing tricalcium phosphate (TCP), hydroxyapatite (HAp), sodium alginate (SA), beeswax (BW), and thymol (TM) was formulated. BW and TM resulted in 3D scaffolds with rougher surfaces and moderate hydrophilic profiles, properties crucial for mediating cell adhesion and proliferation. Moreover, the 3D scaffolds containing BW displayed a significant increase in compressive strength and Young modulus, being comparable to those exhibited by trabecular bone. TM loading prevented the establishment of Staphylococcus aureus and Escherichia coli infections, inhibiting bacterial adhesion and proliferation at the scaffolds' surface. Additionally, the cytocompatibility of the scaffolds was confirmed over 21 days, with the adhesion and proliferation of Human osteoblasts (hOB) at the scaffold's surfaces. Simultaneously, calcium and phosphate ions accumulated at the scaffolds' surface, forming apatite crystals. Therefore, this improved composite mixture showed promising results for being applied in BTE, not only facilitating hOB cell adhesion and proliferation but also avoiding bacterial infection, addressing a critical challenge in implant-based therapies.
- Renewable Photo-Cross-Linkable Polyester-Based Biomaterials: Synthesis, Characterization, and Cytocompatibility AssessmentPublication . Cernadas, Maria Teresa; Pereira, João; Melo, Bruna Daniela Lopes ; de Melo-Diogo, Duarte; Correia, Ilídio Joaquim Sobreira ; Alves, Patrícia; Calvinho, Paula Cristina Nunes FerreiraTThe present work consist of the synthesis of photo-crosslinkable materials, based on unsaturated polyesters (UPs), synthesized from biobased monomers from renewable sources such as itaconic acid and 1,4- butanediol. The UPs were characterized to assess the influence of polycondensation reaction temperature and cross-linking time on their final properties. For this purpose, different UV irradiation exposure periods were tested. Homogeneous, uniform, and transparent films were obtained after 1, 3, and 5 min of UV exposure. These cross-linked films were then characterized. All materials presented high gel content, which was dependent on the reaction’s temperature. The thermal behaviors of the UPs were shown to be similar. In vitro hydrolytic degradation tests showed that the materials can undergo degradation in phosphate-buffered saline (PBS) at pH 7.4 and 37 °C, ensuring their biodegradability over time. Finally, to assess the applicability of the polyesters as biomaterials, their cytocompatibility was determined by using human dermal fibroblasts.
- UV-crosslinked biomaterials: Functionalized polyethylene glycol for tissue adhesive applicationsPublication . Cernadas, Maria Teresa; Ferreira, Mariana; Melo, Bruna Daniela Lopes ; de Melo-Diogo, Duarte; Correia, Ilídio Joaquim Sobreira ; Calvinho, Paula Cristina Nunes Ferreira ; Alves, PatríciaSurgeons around the world face the challenge of effectively and securely treat acute wounds. The most used techniques used to reestablish proper tissue continuity and promote healing comprise surgical tape strips and wound suturing or stapling. However, these have different limitations associated, like additional tissue trauma and patient discomfort. Tissue adhesives have emerged as a promising alternative to traditional wound dressings and have been widely explored for their potential to minimize these drawbacks while improving overall outcomes. This study focused on the preparation of photocrosslinkable biomaterials, synthesized from polyethylene glycol (PEG) functionalized with 2-isocyanatoethyl acrylate (AOI), for potential use as tissue adhesives. The synthesized polymers were then crosslinked using two different UV irradiation times (30 and 120 s) to assess how the crosslinking period impacts the final properties of the films. The materials’ chemical composition and thermal and mechanical behavior were further characterized. Rheologic profile, gel content, hydrolytic degradation, and contact angles were assessed. In addition, cytocompatibility evaluation was also conducted. Overall, the obtained data suggest that the newly synthesized tissue adhesives form flexible, homogeneous, and transparent matrices, exhibiting promising properties for potential tissue adhesive applications.