| Summary: | Dissertação de mestrado integrado em Engenharia Biomédica (área de especialização em Biomateriais, Reabilitação e Biomecânica) In 2014, fish captures and aquaculture supplied ca. 167 million tonnes of fish, of which about 87% were used for human food and 10% was destined for fishmeal and fish oil. The remain 3% is waste that can be used as raw material for direct feeding in aquaculture. Fish sarcoplasmic proteins (FSP) are soluble in water. Large quantities of those proteins are discarded as part of the waste water resulting from fish surimi preparation. FSP constitutes around 25-30% of the total fish muscle protein. FSP comprise heme proteins and enzymes, which are associated with the energy-producing metabolism of the muscle. Herein, FSP from codfish (Gadus morhua) were isolated, resulting in FSP extracts. Both FSP extracts and membranes were physicochemically characterized and their cytocompatibility with human lung fibroblasts (MRC-5 cell line) was also evaluated. By SDS-PAGE, it was possible to define the composition of FSP extracts. From the differential scanning calorimetry (DSC) thermograms, it was possible to define that FSP denature at 44.12 ± 2.34˚C. By circular dichroism (CD) spectroscopy, it was possible to defined that the secondary structure of FSP is mainly composed by α-helix structures. For concentrations lower than 10 mg/mL, no cytotoxicity was observed over 72h of culture. Further on, the FSP extracts were processed into FSP membranes by the spin coating. FSP membranes shown an uniform surface when analyzed by scanning electron microscopy. By CD spectrum, it was verified an increase in the amount of α-helix structures. The FSP membranes were more stable than the FSP extracts, since the denaturation temperature was higher as determined by DSC. FSP membranes were hydrophobic, with a surface zeta potential of -33.4 mV, showing distinctive mechanical properties, with a stiffness of 16.57 ± 3.95 MPa and a yield strength of 23.85 ± 5.97 MPa. Human fibroblasts cultured in direct contact with FSP ...
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