Browsing by Author "Ferraz, Maria Pia"
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- Alginate-nanohydroxyapatite hydrogel system: Optimizing the formulation for enhanced bone regenerationPublication . Barros, J.; Ferraz, Maria Pia; Azeredo, J.; Fernandes, M.H.; Gomes, P.S.; Monteiro, F.J.Ceramic/polymer-based biocomposites have emerged as potential biomaterials tofill, replace, repair or re-generate injured or diseased bone, due to their outstanding features in terms of biocompatibility, bioactivity,injectability, and biodegradability. However, these properties can be dependent on the amount of ceramiccomponent present in the polymer-based composite. Therefore, in the present study, the influence of nanohy-droxyapatite content (30 to 70 wt%) on alginate-based hydrogels was studied in order to evaluate the bestformulation for maximizing bone tissue regeneration. The composite system was characterized in terms ofphysic-chemical properties and biological response, within vitrocytocompatibility assessment with human os-teoblastic cells andex vivofunctional evaluation in embryonic chick segmental bone defects. The main mor-phological characteristics of the alginate network were not affected by the addition of nanohydroxyapatite.However, physic-chemical features, like water-swelling rate, stability at extreme pH values, apatite formation,and Ca2+release were nanoHA dose-dependent. Withinin vitrocytocompatibility assays it was observed thathydrogels with nanoHA 30% content enhanced osteoblastic cells proliferation and expression of osteogenictranscription factors, while those with higher concentrations (50 and 70%) decreased the osteogenic cell re-sponse.Ex vivodata underlined thein vitrofindings, revealing an enhanced collagenous deposition, trabecularbone formation and matrix mineralization with Alg-nanoHA30 composition, while compositions with highernanoHA content induced a diminished bone tissue response.The outcomes of this study indicate that nanohydroxyapatite concentration plays a major role in physic-chemical properties and biological response of the composite system and the optimization of the componentsratio must be met to maximize bone tissue regeneration.
- Anti-sessile bacterial and cytocompatibility properties of CHX-loaded nanohydroxyapatitePublication . Barros, J.; Grenho, Liliana; Fernandes, M.H.; Manuel, C.M.; Melo, L.F.; Nunes, O.C.; Monteiro, F.J.; Ferraz, Maria PiaNanohydroxyapatite possesses exceptional biocompatibility and bioactivity regarding bone cells and tissues, justifying its use as a coating material or as a bone substitute. Unfortunately, this feature may also encourage bacterial adhesion and biofilm formation. Surface functionalization with antimicrobials is a promising strategy to reduce the likelihood of bacterial infestation and colonization on medical devices. Chlorhexidine digluconate is a common and effective antimicrobial agent used for a wide range of medical applications. The purpose of this work was the development of a nanoHA biomaterial loaded with CHX to prevent surface bacterial accumulation and, simultaneously, with good cytocompatibility, for application in the medical field. CHX (5-1500 mg/L) was loaded onto nanoHA discs and the materials were evaluated for CHX adsorption and release profile, physic-chemical features, antibacterial activity against Escherichia coli, Staphylococcus aureus and Staphylococcus epidermidis, and cytocompatibility toward L929 fibroblasts. Results showed that the adsorption of CHX on nanoHA surface occurred by electrostatic interactions between the cationic group of CHX and the phosphate group of nanoHA. The release of CHX from CHX-loaded nanoHA showed a fast initial rate followed by a slower kinetics release, due to constraints caused by dilution and diffusion-limiting processes. NanoHA.50 to nanoHA.1500 showed strong anti-sessile activity, inhibiting bacterial adhesion and the biofilm formation. CHX-nanoHA caused a dose- and time-dependent inhibitory effect on the proliferation of fibroblasts for nanoHA.100 to nanoHA.1500. Cellular behavior on nanoHA.5 and nanoHA.50 was similar to control. Therefore, CHX-loaded nanoHA surfaces appear as a promising alternative to prevention of devices-related infections.
- Antibacterial activity and biocompatibility of three-dimensional nanostructured porous granules of hydroxyapatite and zinc oxide nanoparticles—anin vitroandin vivostudyPublication . Grenho, Liliana; Salgado, C. L.; Fernandes, M. H.; Monteiro, F. J.; Ferraz, Maria PiaCeramic scaffolds are widely studied in the bone tissue engineering field due to their potential in regenerative medicine. However, adhesion of microorganisms on biomaterials with subsequent formation of antibiotic-resistant biofilms is a critical factor in implant-related infections. Therefore, new strategies are needed to address this problem. In the present study, three-dimensional and interconnected porous granules of nanostructured hydroxyapatite (nanoHA) incorporated with different amounts of zinc oxide (ZnO) nanoparticles were produced using a simple polymer sponge replication method. As in vitro experiments, granules were exposed to Staphylococcus aureus and Staphylococcus epidermidis and, after 24 h, the planktonic and sessile populations were assessed. Cytocompatibility towards osteoblast-like cells (MG63 cell line) was also evaluated for a period of 1 and 3 days, through resazurin assay and imaging flow cytometry analysis. As in vivo experiments, nanoHA porous granules with and without ZnO nanoparticles were implanted into the subcutaneous tissue in rats and their inflammatory response after 3, 7 and 30 days was examined, as well as their antibacterial activity after 1 and 3 days of S. aureus inoculation. The developed composites proved to be especially effective at reducing bacterial activity in vitro and in vivo for a weight percentage of 2% ZnO, with a low cell growth inhibition in vitro and no differences in the connective tissue growth and inflammatory response in vivo. Altogether, these results suggest that nanoHA-ZnO porous granules have a great potential to be used in orthopaedic and dental applications as a template for bone regeneration and, simultaneously, to restrain biomaterial-associated infections.
- Assessment of Health and Well-being of Portuguese Population by Environmental and Socioeconomic DeterminantsPublication . Vidal, Diogo Guedes; Barreira, Maria Esmeralda; Oliveira, Gisela; Pontes, Manuela; Maia, Rui Leandro; Ferraz, Maria Pia; Cabeda, José Manuel; Calheiros, José ManuelSustainable development aims for the universal well-being and for integral human development. The 2030 Agenda for Sustainable Development defines the goal SDG3 as “ensure healthy lives and promote well-being for all at all ages”. The promotion of health equity faces challenges of political, social, economic and environmental nature, which are interrelated and influenced by environmental and socioeconomic determinants. Health determinants are intrinsically linked with all SDGs, thus, this work proposes a tailored made index SEHVI - SocioEconomic Health Vulnerability Index aiming to analyse the Portuguese population health and well-being in a quantitative manner.
- Bacteriophage Phi 6 as surrogate and human-harmless viruses to study anti-SARS-CoV-2 approachesPublication . Barros, Joana; Monteiro, Fernando; Ferraz, Maria PiaGiven safety challenges in conducting laboratory work with highly infectious human coronaviruses (pathogenicity, genetic mutations rate, biosafety level 3 and 4 requirements), many researchers have valued the potential of bacteriophages as appropriate viral surrogate to measure humans enveloped virus’ survival, transfer and removal. The use of phage Φ6 seems to be useful as coronavirus surrogate to assess the effectiveness of anti-SARS-CoV-2 approaches, providing important insights concerning COVID-19 pandemic and human public health.
- Cerium and gentamicin antibacterial activity on loaded calcium-phosphates microspheresPublication . Ferraz, Maria Pia; Caetana, Vanessa; Soares, Stephanie; Coelho, Maria João; Cardoso, Inês Lopes; Magalhães, Ricardo; Pina, Cristina Maria San Román Gomes de; M A Lopes
- Complexos catiónicos lipossoma-DNA: um veículo não viral alternativo para terapia genética em tecido ósseoPublication . Ferraz, Maria Pia; Cabral, AndreiaO desenvolvimento de vectores continua a ser um dos grandes problemas em terapia genética. Os diversos tipos de vectores são utilizados com o objectivo de transportar o DNA terapêutico ao núcleo das células-alvo, sendo os mais utilizados os vectores virais, dado a sua eficiência na libertação intracelular do material genético. No entanto, os lipossomas catiónicos, sendo vectores não virais, podem constituir um bom método para a libertação de genes em células do tecido ósseo, dado a sua versatilidade e segurança. The development of vectors is one of the biggest challenges in genetic therapy. The different types of vectors are used with the goal of transporting therapeutic DNA to the target cells nucleus. Viral vecteors are the most used due to their efficiency on intracelular release of genetic material. However, cathonic lipossomes can also be effective for delivering genes to bone tissue cells mainly due to their versatility and safety.
- Detection of Staphylococcus aureus (MRSA/MSSA) in surfaces of dental medicine equipmentPublication . Gonçalves, Eva; Carvalhal, Rui; Mesquita, Rita; Azevedo, Joana; Coelho, Maria João; Magalhães, Ricardo; Ferraz, Maria Pia; Manso, M. Conceição; Gavinha, Sandra; Pina, Cristina Maria San Román Gomes de; Cardoso, Inês LopesMethicillin-Resistant Staphylococcus aureus (MRSA) represents one of the major causes of nosocomial infections, leading to high mortality. Surfaces in clinics, as well as the attending uniform and the hands of the dental doctor can be MRSA reservoirs. Having this in mind, the purpose of this study was to evaluate the presence of Methicillin-Sensitive Staphylococcus aureus (MSSA) and MRSA on dental medicine equipment surfaces. 354 Samples were collected from six equipment surfaces in six attendance areas before and after patient consultation and cultured in a selective medium. Polymerase Chain Reaction (PCR) was used to confirm the identity of bacterial strains as MRSA or MSSA. Data analysis was performed with chi-square tests with Bonferroni correction. It was observed 55.6% of uncontaminated samples. Contamination was: 17.5% MRSA (5.9% of samples collected before patient attendance and 11.6% after); 39.3% MSSA (14.1% collected before and 25.2% after). The prevalence of MRSA and MSSA was significantly higher after patient care. Integrated Clinic represented the most contaminated attendance area (MRSA 41.7%, MSSA 51.2%), the chair arm rest was the most contaminated surface for MRSA (29.7%) and the dental spittoon the most contaminated surface for MSSA (23.5%). Although a low level of contamination was observed, dental clinics, through patients possibly carrying bacteria, may be reservoirs for MRSA and MSSA transmission, and might contribute to potential nosocomial infections.
- Development of silk fibroin/nanohydroxyapatite composite hydrogels for bone tissue engineeringPublication . Ribeiro, Marta; Moraes, Mariana A. de; Beppu, Marisa M.; Garcia, Mónica P.; Fernandes, Maria H.; Monteiro, Fernando J.; Ferraz, Maria PiaThis work presents a novel composite hydrogel consisting of silk fibroin (SF) and nanohydroxyapatite (nanoHA) prepared by a new and innovative method using ethanol as gelling agent capable of forming hydrogels in few minutes. The properties of the composite material, such as the microstructure as well as the chemical and physical properties were studied. Moreover in␣vitro studies of osteoblastic citocompatibility were performed. The microporosity and macroporosity obtained combined with interconnected porous structure and a uniform dispersion of nanoHA particles throughout the fibroin matrix makes composite hydrogel suitable for bone regeneration. The compression modulus of composite hydrogels was increased as the nanoHA concentration increased from 10 to 15 wt.% and the water uptake ability of these materials decreased with the incorporation of nanoHA. The metabolic and alkaline phosphatase activities of osteoblastic cells were improved with the incorporation of nanoHA in the SF matrix providing a more promising material for bone tissue engineering.
- Efeito da doxiciclina e da minociclina em células osteoblásticas humanas: estudos in vitroPublication . Coelho, Maria João; Pina, Cristina Maria San Román Gomes de; Ferraz, Maria PiaA doxiciclina e a minociclina são antibióticos utilizados para eliminar infecções que surgem após o processo cirúrgico e que parecem exercer uma acção benéfica sobre o metabolismo ósseo. Os resultados obtidos neste estudo mostraram que baixas concentrações destes fármacos(1-5 μg.ml-1) estimularam a proliferação das células de medula óssea humana. A exposição das células a 10 μg.ml-1 de minociclina pareceu estimular o aparecimento de uma população celular mais proliferativa mas menos diferenciada. As concentrações de 10 μg.ml-1 de doxiciclina e 25 μg.ml-1 de minociclina atrasaram a mineralização e concentrações mais elevadas destes antibióticos (25 μg.ml-1 de doxiciclina e 50 μg.ml-1 de minociclina) foram citotóxicas. Doxycycline and minocycline are antibiotics used to eliminate infections that arise after the surgical procedure that seem to have a beneficial action in bone metabolism. Results showed that low concentrations of these drugs (1-5 μg.ml-1) stimulated human bone marrow cell proliferation. The exposure of cells to 10 μg.ml-1 minocycline stimulated the emergence of a more proliferative population but less differentiated. Concentrations of 10 μg.ml-1 doxycycline and 25 μg.ml-1 minocycline delayed the mineralization and higher concentrations of these antibiotics (25 μg.ml-1 doxycycline and 50 μg.ml-1 minocycline) were cytotoxic.