Preliminary evaluation of fish cartilage as a promising biomaterial in cartilage tissue engineering.

Fish cartilage is known as a valuable source of natural biomaterials due to its unique composition and properties. It contains a variety of bioactive components that contribute to its potential applications in different domains such as tissue engineering. The present work aimed to consider the properties of backbone cartilage from fish with a cartilaginous skeleton, including elasmobranch (reticulate whipray: Himantura uarnak and milk shark: Rhizoprionodon acutus) and sturgeon (beluga: Huso huso). The histomorphometric findings showed that the number of chondrocytes was significantly higher in reticulate whipray and milk shark compared to beluga (p < 0.05). The highest GAGs content was recorded in reticulate whipray cartilage compared to the other two species (p < 0.05). The cartilage from reticulate whipray and beluga showed higher collagen content than milk shark cartilage (p < 0.05), and the immunohistochemical assay for type II collagen (Col II) showed higher amounts of this component in reticulate whipray compared to the other two species. Young's modulus of the cartilage from reticulate whipray was significantly higher than that of milk shark and beluga (p < 0.05), while no significant difference was recorded between Young's modulus of the cartilage from milk shark and beluga. The gene expression of ACAN, Col II, and Sox9 showed that the cartilage-ECM from three species was able to induce chondrocyte differentiation from human adipose tissue-derived stem cells (hASCs). From these results, it can be concluded that the cartilage from three species, especially reticulate whipray, enjoys the appropriate biological properties and provides a basis for promoting its applications in the field of cartilage tissue engineering.

Anti-Salmonella Activity and Peptidomic Profiling of Peptide Fractions Produced from Sturgeon Fish Skin Collagen (Huso huso) Using Commercial Enzymes.

This study investigated peptide fractions from fish skin collagen for antibacterial activity against Escherichia coli and Salmonella strains. The collagen was hydrolyzed with six commercial proteases, including trypsin, Alcalase, Neutrase, Flavourzyme, pepsin and papain. Hydrolyzed samples obtained with trypsin and Alcalase had the largest number of small peptides (molecular weight <10 kDa), while the hydrolysate produced with papain showed the lowest degree of hydrolysis and highest number of large peptides. Four hydrolysates were found to inhibit the growth of the Gram-negative bacteria, with papain hydrolysate showing the best activity against E. coli, and Neutrase and papain hydrolysates showing the best activity against S. abony; hydrolysates produced with trypsin and pepsin did not show detectable antibacterial activity. After acetone fractionation of the latter hydrolysates, the peptide fractions demonstrated enhanced dose-dependent inhibition of the growth (colony-forming units) of four Salmonella strains, including S. abony (NCTC 6017), S. typhimurium (ATCC 13311), S. typhimurium (ATCC 14028) and S. chol (ATCC 10708). Shotgun peptidomics analysis of the acetone fractions of Neutrase and papain hydrolysates resulted in the identification of 71 and 103 peptides, respectively, with chain lengths of 6-22 and 6-24, respectively. This work provided an array of peptide sequences from fish skin collagen for pharmacophore identification, structure-activity relationship studies, and further investigation as food-based antibacterial agents against pathogenic microorganisms.

Biochemical and structural characterization of sturgeon fish skin collagen (Huso huso).

The potential use of sturgeon fish skin waste (Huso huso), an Iranian major sturgeon species, as a rich source for collagen extraction was evaluated. Yields of ASC and PSC obtained by acidic and enzymatic extractions were 9.98% and 9.08% (based on wet weight), respectively. SDS-PAGE profiles of both collagens led to classification of the proteins as type I with two different α chains (α1 and α2 ). Scanning electron microscopy (SEM) of the collagen sponges indicated dense sheet-like film linked by random-coiled filaments. Glycine was the most predominant amino acid, and the imino acids contents were 21.14% and 21.58% for ASC and PSC, respectively. Fourier-transform infrared spectra (FTIR) confirmed that pepsin digestion did not disrupt PSC triple helical structure. Denaturation and melting temperatures of ASC and PSC were 29.34°C, 92.03°C, and 29.89°C, 88.93°C, respectively. Thus, the sturgeon fish skin waste could serve as an alternative collagenous source for biomedical materials, food, and pharmaceutical applications. PRACTICAL APPLICATIONS: Beluga (Huso huso) is one of the most important sturgeon fish on the Caspian Sea and aquaculture industries. With the exception of the meat and caviar, wastes generated after their processing are usually discarded. Skin and cartilage of sturgeon fish are the by-products of the processing, and they are often discarded as waste or used for low-value purposes, although they are a good source for production of collagen-based biomaterials. Collagen type I is the most abundant collagen in the skin and this work reports the sturgeon fish skin as an important collagen resource with potential for use in the food, biomedical, and cosmetic industries.

Preparation and characterization agar-based nanocomposite film reinforced by nanocrystalline cellulose.

Nanocrystalline cellulose (NCC) was prepared from microcrystalline cellulose (MCC) with particle size of 24.7 µm using sulfuric acid hydrolysis technique. The obtained NCC revealed size of 0-100 nm, which the major part of them was about 30 nm. Then different contents (2.5, 5 and 10 wt%) of these NCC incorporated in agar film solution and the morphology, structure, and properties of the nanocomposite films were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transforms infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), mechanical, physical and optical testing. Results showed that the water vapor permeability (WVP) and water solubility (WS) of the agar-based nanocomposite films significantly (P<0.05) decreased about 13% and 21%, respectively, upon increasing the NCC content to 10%. Tensile strength (TS) and Young's modulus (YM) values of nanocomposite films significantly increased (P≤0.05) with addition of NCC, whereas the elongation percent (E%) decreased not significantly (P>0.05). In addition, swelling percentage, transparency and light transmission of the films were decreased by incorporating NCC into polymer matrix.