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- Hyaluronic acid - Based wound dressings: A reviewPublication . Graça, Mariana F. P.; Miguel, Sónia P.; Cabral, Cátia S. D.; Correia, I.J.Hyaluronic acid (HA), a non-sulfated glycosaminoglycan (GAG), is a major component of skin extracellular matrix (ECM) and it is involved in the inflammatory response, angiogenesis, and tissue regeneration process. Due to the intrinsic properties of HA (such as biocompatibility, biodegradability and hydrophilic character), it has been used to produce different wound dressings, namely sponges, films, hydrogels, and electrospun membranes. Herein, an overview of the different HA-based wound dressings that have been produced so far is provided as well as the future directions regarding the strategies aimed to improve the mechanical stability of HA-based wound dressings, along with the incorporation of biomolecules intended to ameliorate their biological performance during the healing process.
- Comparative study of the therapeutic effect of Doxorubicin and Resveratrol combination on 2D and 3D (spheroids) cell culture modelsPublication . Barros, Andreia; Costa, Elisabete C.; Nunes, Ana Raquel Santos; Diogo, Duarte Miguel de Melo; Correia, Ilídio Joaquim SobreiraThe assessment of drug-combinations for pancreatic cancer treatment is usually performed in 2D cell cultures. In this study, the therapeutic effect and the synergistic potential of a particular drug-combination towards 2D and 3D cell cultures of pancreatic cancer were compared for the first time. Thus, the effect of Doxorubicin:Resveratrol (DOX:RES) combinations (at molar ratios ranging from 5:1 to 1:5) in the viability of PANC-1 cells cultured as 2D monolayers and as 3D spheroids was analyzed. The results showed that the cells’ viability was more affected when DOX:RES combinations containing higher contents of RES (1:2–1:5 molar ratios) were used. This can be explained by the ability of RES to reduce the P-glycoprotein (P-gp)-mediated efflux of DOX. Further, it was also revealed that the synergic effect of this drug combination was different in 2D and in 3D cell cultures. In fact, despite of the 1:4 and 1:5 DOX:RES ratios being both synergistic for both types of PANC-1 cell cultures, their Combination Indexes (CI) in the monolayers were lower than those attained in spheroids. Overall, the obtained results revealed that the DOX:RES combination is promising for pancreatic cancer treatment and corroborate the emergent need to evaluate drug combinations in 3D cell cultures.
- D-α-tocopheryl polyethylene glycol 1000 succinate functionalized nanographene oxide for cancer therapyPublication . Diogo, Duarte Miguel de Melo; Silva, Cleide Isabel Pais; Costa, Elisabete C.; Louro, Ricardo; Correia, Ilídio Joaquim SobreiraAim: To evaluate the therapeutic capacity of D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS)-functionalized nanographene oxide (nGO) in breast cancer cells. Methods: TPGS-functionalized nGO-based materials were obtained through two different approaches: a simple sonication method and a one-pot hydrothermal treatment. Results: TPGS coating successfully improved the stability of the nGO-based materials. The nanomaterials that underwent the hydrothermal procedure generated a 1.4- to 1.6-fold higher temperature variation under near infrared laser irradiation than those prepared only by sonication. In vitro, the TPGS/nGO derivatives reduced breast cancer cells’ viability and had an insignificant effect on healthy cells. Furthermore, the combined application of TPGS/nGO derivatives and near infrared light generated an improved therapeutic effect. Conclusion: TPGS/nGO derivatives are promising materials for breast cancer phototherapy.
- Electrospun polymeric nanofibres as wound dressings: A reviewPublication . Miguel, Sónia P.; Figueira, Daniela Sofia Rodrigues; Simões, Déborah; Ribeiro, MP.; Coutinho, Paula; Ferreira, Paula; Correia, Ilídio Joaquim SobreiraSkin wounds have significant morbidity and mortality rates associated. This is explained by the limited effectiveness of the currently available treatments, which in some cases do not allow the reestablishment of the structure and functions of the damaged skin, leading to wound infection and dehydration. These drawbacks may have an impact on the healing process and ultimately prompt patients’ death. For this reason, researchers are currently developing new wound dressings that enhance skin regeneration. Among them, electrospun polymeric nanofibres have been regarded as promising tools for improving skin regeneration due to their structural similarity with the extracellular matrix of normal skin, capacity to promote cell growth and proliferation and bactericidal activity as well as suitability to deliver bioactive molecules to the wound site. In this review, an overview of the recent studies concerning the production and evaluation of electrospun polymeric nanofibrous membranes for skin regenerative purposes is provided. Moreover, the current challenges and future perspectives of electrospun nanofibrous membranes suitable for this biomedical application are highlighted.
- New drug-eluting lenses to be applied as bandages after keratoprosthesis implantationPublication . Carreira, Ana; Ferreira, Paula; Ribeiro, MP.; Correia, Tiago R.; Coutinho, Paula Isabel Teixeira Gonçalves; Correia, Ilídio Joaquim Sobreira; Gil, MariaCorneal tissue is the most commonly transplanted tissue worldwide. This work aimed to develop a new drug-eluting contact lens that may be used as a bandage after keratoprosthesis. During this work, films were produced using poly(vinyl alcohol) (PVA) and chitosan (CS) crosslinked with glyoxal (GL). Vancomycin chlorhydrate (VA) was impregnated in these systems by soaking. Attenuated total reflectance – Fourier transform infrared spectroscopy was used to confirm crosslinking. The cytotoxic and drug release profile, hydrophilicity, thermal and biodegradation as well as swelling capacity of the samples were assessed through in vitro studies. PVA and PVA/CS films were obtained by crosslinking with GL. The films were transparent, flexible with smooth surfaces, hydrophilic and able to load and release vancomycin for more than 8 h. Biodegradation in artificial lachrymal fluid (ALF) with lysozyme at 37 °C showed that mass loss was higher for the samples containing CS. Also, the samples prepared with CS showed the formation of pores which were visualized by SEM. All samples revealed a biocompatible character after 24 h in contact with cornea endothelial cells. As a general conclusion it was possible to determine that the 70PVA/30CS film showed to combine the necessary features to prepare vancomycin-eluting contact lenses to prevent inflammation after corneal substitution.
- Design and production of sintered β-tricalcium phosphate 3D scaffolds for bone tissue regenerationPublication . Santos, Carlos Filipe Lopes; Silva, Abílio P.; Lopes, Luís; Pires, Inês; Correia, Ilídio Joaquim SobreiraThe characteristics of sintered β-tricalcium phosphate (β-TCP) scaffolds produced by 3D printing were studied by means of X-ray diffraction, Scanning Electron Microscopy, Fourier transform infrared spectroscopy, uniaxial compression tests and cytotoxicity tests, using human osteoblast cells. The results reported include details of the β-TCP scaffolds' porosity, density, phase stability, mechanical behavior and cytotoxic profile. Collectively, these properties are fundamental for the future application of these scaffolds as bone substitutes for individualized therapy.
- IR780 based nanomaterials for cancer imaging and photothermal, photodynamic and combinatorial therapiesPublication . Alves, Cátia; Sousa, Ana Rita Lima; Diogo, Duarte Miguel de Melo; Correia, Ilídio Joaquim SobreiraIR780, a molecule with a strong optical absorption and emission in the near infrared (NIR) region, is receiving an increasing attention from researchers working in the area of cancer treatment and imaging. Upon irradiation with NIR light, IR780 can produce reactive oxygen species as well as increase the body temperature, thus being a promising agent for application in cancer photodynamic and photothermal therapy. However, IR780’s poor water solubility, fast clearance, acute toxicity and low tumor uptake may limit its use. To overcome such issues, several types of nanomaterials have been used to encapsulate and deliver IR780 to tumor cells. This mini-review is focused on the application of IR780 based nanostructures for cancer imaging, and photothermal, photodynamic and combinatorial therapies.
- Microneedle-based delivery devices for cancer therapy: a reviewPublication . Moreira, André; Rodrigues, Ana Carolina Félix; Jacinto, Telma A.; Miguel, Sónia; Costa, Elisabete; Correia, I.J.Macroscale delivery systems that can be locally implanted on the tumor tissue as well as avoid all the complications associated to the systemic delivery of therapeutics have captured researchers' attention, in recent years. Particularly, the microneedle-based devices can be used to efficiently deliver both small and macro-molecules, like chemotherapeutics, proteins, and genetic material, along with nanoparticle-based anticancer therapies. Such capacity prompted the application of microneedle devices for the development of new anticancer vaccines that can permeate the tumor tissue and simultaneously improve the effectiveness of therapeutic agents. Based on the promising results demonstrated by the microneedle systems in the local administration of anticancer therapeutics, this review summarizes the different microneedle formulations developed up to now aimed for application on cancer therapy (mphasizing those produced with polymers). Additionally, the microneedles' general properties, type of therapeutic approach and its main advantages are also highlighted.
- Mitoxantrone-loaded lipid nanoparticles for breast cancer therapy – quality-by-design approach and efficacy assessment in 2D and 3D in vitro cancer modelsPublication . Granja, Andreia; Sousa, Rita Lima; Alves, Cátia; Diogo, Duarte de Melo; Pinheiro, Marina; Sousa, Célia T.; Correia, I.J.; Reis, SaletteBreast cancer is the leading cause of cancer-related deaths among women worldwide. The conventional chemotherapeutic regimens used in the treatment of this disease often lead to severe side-effects and reduced efficacy. In this study, a novel drug delivery system for the chemotherapeutic drug mitoxantrone (Mito) was developed using solid lipid nanoparticles (SLN). The production of the SLN was carried out using an organic-solvent-free, low-cost method and optimized using a Box-Behnken design. SLN presented adequate size for cancer-related applications, more than 90% of EE% and remained stable for at least 6 months. A much higher drug release was obtained at acidic pH (mimicking the endosomal compartment) than plasmatic pH, highlighting the potential of the nanosystem for tumor drug delivery. Additionally, SLN were non-hemolytic and cytocompatible, even at high concentrations of lipid. A significantly higher anti-cancer efficacy was obtained for Mito-loaded SLN comparing to the free drug at different concentrations in MCF-7 2D models. Finally, the nanoformulation was evaluated in heterotypic breast cancer spheroids showing capacity to penetrate the tridimensional structure and ability to induce a high anti-tumoral effect, similarly to the free drug. Overall, these results support that the developed SLN are effective Mito nanocarriers for the treatment of breast cancer.
- Electronic Structure of Low-Spin Ferric Porphyrins: 13C NMR Studies of the Influence of Axial Ligand OrientationPublication . Louro, Ricardo; Correia, I. J.; Brennan, Lorraine; Coutinho, Isabel; Xavier, António; Turner, DavidHeteronuclear multiple quantum NMR is used to measure the paramagnetic 13C shifts of the α substituents of the hemes in five different tetraheme ferricytochromes c3. The shifts of the 20 bis-histidine ligated hemes are assigned and then analyzed in terms of a model based on the π molecular orbitals of the heme under perturbed D4 symmetry, which yields the orientation of the rhombic perturbation, θ, and an energy splitting parameter, ΔE. Comparison of these parameters with crystal structures provides a test of the nature and extent of the influence of axial ligand orientation on the electronic structure of the heme. Despite possible differences between structures in solution and in the crystal, a clear correlation is found between θ and the resultant of the normals to the imidazole planes, and between ΔE and the angle between the normals. A weaker dependence of ΔE upon θ is also apparent. This is analogous to the results of low-temperature EPR studies of model compounds, which have been attributed to pseudo-Jahn−Teller distortion of the porphyrin. However, the effect is also predicted by extended Hückel calculations made with undistorted geometries. This work demonstrates that the variation in the electronic structure of bis-histidinyl hemes c is dominated by the geometry of the axial ligands and that other perturbations, such as asymmetric substitution of the porphyrin or low symmetry of the surrounding protein, are relatively minor. The correlations with θ and ΔE can, therefore, be used to determine the ligand geometry with sufficient accuracy to detect differences between structures in solution and in the crystal. The analysis can also be used to locate the principal axes of the magnetic susceptibility tensors of ferrihemes as well as providing orientational constraints for the axial ligands for the calculation of solution structures of paramagnetic proteins. This is particularly important since paramagnetic relaxation may make it impossible to observe NOE effects to the imidazole protons, leaving the geometry of the heme pocket poorly defined.