Smart/stimuli-responsive liposome loaded hydrogels with dual delivery potential for tissue engineering applications

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Silica Aerogel-Polycaprolactone Scaffolds for Bone Tissue Engineering

Publication . Pontinha, Ana; Moreira, Eliana Barbosa Da Silva; Melo, Bruna L.; Melo-Diogo, Duarte de; Correia, I.J.; Alves, Patrícia

Silica aerogel is a material composed of SiO2 that has exceptional physical properties when utilized for tissue engineering applications. Poly-ε-caprolactone (PCL) is a biodegradable polyester that has been widely used for biomedical applications, namely as sutures, drug carriers, and implantable scaffolds. Herein, a hybrid composite of silica aerogel, prepared with two different silica precursors, tetraethoxysilane (TEOS) or methyltrimethoxysilane (MTMS), and PCL was synthesized to fulfil bone regeneration requirements. The developed porous hybrid biocomposite scaffolds were extensively characterized, regarding their physical, morphological, and mechanical features. The results showed that their properties were relevant, leading to composites with different properties. The water absorption capacity and mass loss were evaluated as well as the influence of the different hybrid scaffolds on osteoblasts’ viability and morphology. Both hybrid scaffolds showed a hydrophobic character (with water contact angles higher than 90°), low swelling (maximum of 14%), and low mass loss (1–7%). hOB cells exposed to the different silica aerogel-PCL scaffolds remained highly viable, even for long periods of incubation (7 days). Considering the obtained results, the produced hybrid scaffolds may be good candidates for future application in bone tissue engineering.

2023-06-14Journal article

Open access

Dextran-Based Injectable Hydrogel Composites for Bone Regeneration

Publication . Alves, Patrícia; Simão, Ana Filipa; Graça, Mariana F. P.; Mariz, Marcos; Correia, I.J.; Ferreira, Paula

Currently, bone infections caused by diseases or injuries are a major health issue. In addition, the conventional therapeutic approaches used to treat bone diseases or injuries present several drawbacks. In the area of tissue engineering, researchers have been developing new alternative therapeutic approaches, such as scaffolds, to promote the regeneration of injured tissues. Despite the advantages of these materials, most of them require an invasive surgical procedure. To overcome these problems, the main focus of this work was to develop scaffolds for bone regeneration, which can be applied using injectable hydrogels that circumvent the use of invasive procedures, while allowing for bone regeneration. Throughout this work, injectable hydrogels were developed based on a natural polymer, dextran, along with the use of two inorganic compounds, calcium β-triphosphate and nanohydroxyapatite, that aimed to reinforce the mechanical properties of the 3D mesh. The materials were chemically characterized considering the requirements for the intended application: the swelling capacity was evaluated, the degradation rate in a simulated physiological environment was assessed, and compression tests were performed. Furthermore, vancomycin was incorporated into the polymeric matrices to obtain scaffolds with antibacterial performance, and their drug release profile was assessed. The cytotoxic profile of the hydrogels was assessed by an MTS assay, using osteoblasts as model cells. The data obtained demonstrated that dextran-based hydrogels were successfully synthesized, with a drug release profile with an initial burst between 50 and 80% of the drug. The hydrogels possess fair biocompatibility. The swelling capacity showed that the stability of the samples and their degradation profile is compatible with the average time period required for bone regeneration (usually about one month) and have a favorable Young’s modulus (200–300 kPa). The obtained hydrogels are well-suited for bone regeneration applications such as infections that occur during implantation or bone graft substitutes with antibiotics.

2023-11-23Journal article

Open access

UV-crosslinked biomaterials: Functionalized polyethylene glycol for tissue adhesive applications

Publication . Cernadas, Maria Teresa; Ferreira, Mariana; Melo, Bruna Daniela Lopes ; de Melo-Diogo, Duarte; Correia, Ilídio Joaquim Sobreira ; Calvinho, Paula Cristina Nunes Ferreira ; Alves, Patrícia

Surgeons 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.

2025-11-21Article

Open access