CICECO-Aveiro Institute of Materials

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Publications

Multi-material cellular structured orthopedic implants design: In vitro and bio-tribological performance

Publication . Costa, M.M.; Lima, R.; Alves, N.; Silva, N.A.; Gasik, M.; Bartolomeu, F.; Miranda, G.

In this study, Selective Laser Melting (SLM) was used to produce mono-material Ti64Al4V- and NiTi-cubic cellular structures with an open-cell size and wall thickness of 500 μm and 100 μm, respectively. Bioactive beta-tricalcium phosphate (βTCP) and polymer poly-ether-ether ketone (PEEK) were used to fill the produced structures open-cells, thus creating multi-material components. These structures were characterized in vitro in terms of cell viability, adhesion, differentiation and mineralization. Also, bio-tribological experiments were performed against bovine plate to mimic the moment of implant insertion. Results revealed that metabolic activity and mineralization were improved on SLM mono-material groups, when compared to the control group. All cell metrics were improved with the addition of PEEK, conversely to βTCP where no significant differences were found. These results suggest that the proposed solutions can be used to improve implants performance.

2022Journal article

Open access

Uncovering the bioactivity of Aurantiochytrium sp.: a comparison of extraction methodologies

Publication . Reboleira, João; Félix, Rafael; Vicente, Tânia F. L.; Januário, Adriana P.; Félix, Carina; Melo, Marcelo M.R. de; Silva, Carlos M.; Ribeiro, Ana C.; Saraiva, Jorge A.; Bandarra, Narcisa M.; Sapatinha, Maria; Paulo, Maria C.; Coutinho, Joana; Lemos, Marco F.L.

Aurantiochytrium sp. is an emerging alternative source of polyunsaturated fatty acids (PUFAs), docosahexaenoic acid (DHA), and squalene, playing an important role in the phasing out of traditional fish sources for these compounds. Novel lipid extraction techniques with a focus on sustainability and low environmental footprint are being developed for this organism, but the exploration of other added-value compounds within it is still very limited. In this work, a combination of novel green extraction techniques (high hydrostatic pressure extraction (HPE) and supercritical fluid extraction (SFE)) and traditional techniques (organic solvent Soxhlet extraction and hydrodistillation (HD)) was used to obtain lipophilic extracts of Aurantiochytrium sp., which were then screened for antioxidant (DPPH radical reduction capacity and ferric-reducing antioxidant potential (FRAP) assays), lipid oxidation protection, antimicrobial, anti-aging enzyme inhibition (collagenase, elastase and hyaluronidase), and anti-inflammatory (inhibition of NO production) activities. The screening revealed promising extracts in nearly all categories of biological activity tested, with only the enzymatic inhibition being low in all extracts. Powerful lipid oxidation protection and anti-inflammatory activity were observed in most SFE samples. Ethanolic HPEs inhibited both lipid oxidation reactions and microbial growth. The HD extract demonstrated high antioxidant, antimicrobial, and antiinflammatory activities making, it a major contender for further studies aiming at the valorization of Aurantiochytrium sp. Taken together, this study presents compelling evidence of the bioactive potential of Aurantiochytrium sp. and encourages further exploration of its composition and application.

2021Journal article

Restricted access

Supercritical CO2 extraction of Aurantiochytrium sp. biomass for the enhanced recovery of omega-3 fatty acids and phenolic compounds

Publication . Melo, M.M.R. de; Sapatinha, M.; Pinheiro, J.; Lemos, M.F.L.; Bandarra, N.M.; Batista, I.; Paulo, M.C.; Coutinho, J.; Saraiva, J.A.; Portugal, I; Silva, C.M.

The microalgae Aurantiochytrium sp. is a strong alternative source of ω-3 fatty acids, including ocosahexaenoic acid (DHA). This work encompasses the optimization of SFE conditions to maximize the total extraction yield (ηTotal), DHA content (CDHA), total phenolics content (TPC), and antioxidant capacity (AOC) of the extracts produced from Aurantiochytrium sp. biomass. A full factorial experimental plan was performed, comprising three factors (pressure, temperature, and flow rate) and two levels (200−300 bar, 40−80 °C, and 6–12 gmin−1, respectively). The maximum and minimum experimental results were ηTotal = 2.1 and 13.4 wt.%, CDHA= 27.3 and 39.3 wt.%, TPC =1.19 and 2.24 mgGAE g−extract 1 , and AOC = 0.3 and 1.4 mg g− TEAC extract 1. Under the studied experimental conditions, increasing pressure up to 300 bar is the optimum to rise both ηTotal and CDHA. Temperature increase from 40 to 80 °C leads to opposing effects: it favors the concentration of phenolics in the supercritical extracts at the expenses of decreasing DHA content and total yield. Surface models were adjusted to ηTotal, CDHA and TPC data, and the goodness of the fits ranged from coefficients of determination of 0.752-0.711 (TPC) to 0.997-0.994 (CDHA). Under optimized conditions, supercritical extracts exhibited a DHA content more than 3.5-fold richer than fish oil, and 7.9-fold richer than the best alternative microalgae species (Pavlova lutheri) found in the literature.

2020Journal article

Restricted access

On the mechanical properties of PLC–bioactive glass scaffolds fabricated via BioExtrusion

Publication . Fiedler, T.; Videira, A.C.; Bartolo, Paulo; Strauch, M.; Murch, G.E.; Ferreira, J.M.F.

This paper addresses the mechanical characterization of polycaprolactone (PCL)–bioglass (FastOs®BG) composites and scaffolds intended for use in tissue engineering. Tissue engineering scaffolds support the self-healing mechanism of the human body and promote the regrowth of damaged tissue. These implants can dissolve after successful tissue regeneration minimising the immune reaction and the need for revision surgery. However, their mechanical properties should match surrounding tissue in order to avoid strain concentration and possible separation at the interface. Therefore, an extensive experimental testing programme of this advanced material using uni-axial compressive testing was conducted. Tests were performed at low strain rates corresponding to quasi-static loading conditions. The initial elastic gradient, plateau stress and densification strain were obtained. Tested specimens varied according to their average density and material composition. In total, four groups of solid and robocast porous PCL samples containing 0, 20, 30, and 35% bioglass, respectively were tested. The addition of bioglass was found to slightly decrease the initial elastic gradient and the plateau stress of the biomaterial scaffolds.

2015-12Journal article

Restricted access

Funding agency

Fundação para a Ciência e a Tecnologia

Funding programme

6817 - DCRRNI ID

Funding Award Number

UIDB/50011/2020