Ivo Manuel Ascensão Aroso

Design of controlled release systems for THEDES—Therapeutic deep eutectic solvents, using supercritical fluid technology

Deep eutectic solvents (DES) can be formed by bioactive compounds or pharmaceutical ingredients. A therapeutic DES (THEDES) based on ibuprofen, a non-steroidal anti-inflammatory drug (NSAID), and menthol was synthesized and its thermal behavior was analyzed by differential scanning calorimetry (DSC). A controlled drug delivery system was developed by impregnating a starch:poly-ϵ-caprolactone polymeric blend (SPCL 30:70) with the menthol:ibuprofen THEDES in different ratios (10 and 20 wt%), after supercritical fluid sintering at 20 MPa and 50 °C. The morphological characterization of SPCL matrices impregnated with THEDES was performed by scanning electron microscopy (SEM) and micro-computed tomography (micro-CT). Drug release studies were carried out in a phosphate buffered saline. The results obtained provide important clues for the development of carriers for the sustainable delivery of bioactive compounds.

Dissolution enhancement of active pharmaceutical ingredients by therapeutic deep eutectic systems

A therapeutic deep eutectic system (THEDES) is here defined as a deep eutectic solvent (DES) having an active pharmaceutical ingredient (API) as one of the components. In this work, THEDESs are proposed as enhanced transporters and delivery vehicles for bioactive molecules. THEDESs based on choline chloride (ChCl) or menthol conjugated with three different APIs, namely acetylsalicylic acid (AA), benzoic acid (BA) and phenylacetic acid (PA), were synthesized and characterized for thermal behaviour, structural features, dissolution rate and antibacterial activity. Differential scanning calorimetry and polarized optical microscopy showed that ChCl:PA (1:1), ChCl:AA (1:1), menthol:AA (3:1), menthol:BA (3:1), menthol:PA (2:1) and menthol:PA (3:1) were liquid at room temperature. Dissolution studies in PBS led to increased dissolution rates for the APIs when in the form of THEDES, compared to the API alone. The increase in dissolution rate was particularly noticeable for menthol-based THEDES. Antibacterial activity was assessed using both Gram-positive and Gram-negative model organisms. The results show that all the THEDESs retain the antibacterial activity of the API. Overall, our results highlight the great potential of THEDES as dissolution enhancers in the development of novel and more effective drug delivery systems.

Cork extracts reduce UV-mediated DNA fragmentation and cell death

UV radiation is known to induce the premature aging of human skin and to contribute to the occurrence of different skin cancers. High doses of UVA (which is able to penetrate through the epidermis into the dermis) and/or UVB radiation (which only affects the epidermis) lead to cellular oxidative damage compromising the recovery of the normal functions of the cells. This cellular damage is mainly driven by the generation of reactive oxygen species (ROS) that alter the redox status of the intracellular milieu, affecting the cellular metabolic activity, leading to DNA damage, apoptosis and, consequently, to a drastic decrease in the number of live cells, compromising the function of the skin. A series of polyphenolic fractions were extracted from the outer bark (cork) of Quercus suber L., and tested for their capacity to reduce the cellular damage promoted by the ROS produced during UV exposure. This was evaluated after exposing L929 fibroblasts to UV radiation in the presence and absence of the cork extracts. In all the cases the extracts at the concentration of 75 μg ml−1 demonstrated the capacity to preserve cell metabolic activity and their typical morphology, as well as to avoid DNA fragmentation after exposure to UV radiation. We were also able to correlate these findings with the intracellular reduction of ROS species and the presence of higher proportions of castalagin and vescalagin in the extracts. Our data prove that cork is a relevant source of antioxidant compounds able to act in the cellular environment, protecting cells against oxidation, reducing the number of ROS species and limiting the negative impact of UV radiation. These extracts can be further exploited in the preparation of anti-UV formulations for skin protection.

In vitro bioactivity studies of ceramic structures isolated from marine sponges.

In this work, we focused on the potential of bioceramics from different marine sponges-namely Petrosia ficiformis, Agelas oroides and Chondrosia reniformis-for novel biomedical/industrial applications. The bioceramics from these sponges were obtained after calcination at 750 °C for 6 h in a furnace. The morphological characteristics were evaluated by scanning electron microscopy (SEM). The in vitro bioactivity of the bioceramics was evaluated in simulated body fluid (SBF) after 14 and 21 d. Observation of the bioceramics by SEM after immersion in SBF solution, coupled with spectroscopic elemental analysis (EDS), showed that the surface morphology was consistent with a calcium-phosphate (Ca/P) coating, similar to hydroxyapatite crystals (HA). Evaluation of the characteristic peaks of Ca/P crystals by Fourier transform infrared spectroscopy and x-ray diffraction further confirmed the existence of HA. Cytotoxicity studies were carried out with the different ceramics and these were compared with a commercially available Bioglass(®). In vitro tests demonstrated that marine bioceramics from these sponges are non-cytotoxic and have the potential to be used as substitutes for synthetic Bioglass(®).

Bioactive ceramics for tissue engineering and regenerative medicine derived from marine sponges

Introduction: Decellularized engineered extracellular matrices (ECM) are used in a variety of regenerative medicine applications. Existing decellularization strategies rely on cell lysis and generally result in a variable but significant impairment of the ECM structure/composition. As an alternative, we aimed at activating the apoptotic pathway in order to decellularize engineered matrices while preserving their osteo-inductive properties [1]. Materials and methods: We generated a death-inducible, immortalized human Mesenchymal Stromal Cell (hMSC) line [2]. Cells were seeded on ceramic scaffolds and cultured for 4 weeks in osteogenic medium in a 3D perfusion bioreactor system (U-cup, Cellec). The ECM was decellularized by direct supply of the apoptotic inducer in the 3D culture system. Grafts were implanted in a rat cranial defect model to assess their regenerative potential after 12 weeks. Results: Cells were successfully seeded and differentiated, leading to deposition of a dense ECM during 3D culture. The apoptosis induction allowed for efficient decellularization while preserving the secreted matrix. These “apoptized” cell-free ECM coated constructs induced superior bone regeneration than control materials (Fig. 2). Areas of de novo bone formation not connected with surrounding bone suggest osteoinductive properties of the grafts.