Collagen films from swim bladders: preparation method and properties

Swim bladder-derived biomaterials: structures, compositions, properties, modifications, and biomedical applications

Animal-derived biomaterials have been extensively employed in clinical practice owing to their compositional and structural similarities with those of human tissues and organs, exhibiting good mechanical properties and biocompatibility, and extensive sources. However, there is an associated risk of infection with pathogenic microorganisms after the implantation of tissues from pigs, cattle, and other mammals in humans. Therefore, researchers have begun to explore the development of non-mammalian regenerative biomaterials. Among these is the swim bladder, a fish-derived biomaterial that is rapidly used in various fields of biomedicine because of its high collagen, elastin, and polysaccharide content. However, relevant reviews on the biomedical applications of swim bladders as effective biomaterials are lacking. Therefore, based on our previous research and in-depth understanding of this field, this review describes the structures and compositions, properties, and modifications of the swim bladder, with their direct (including soft tissue repair, dural repair, cardiovascular repair, and edible and pharmaceutical fish maw) and indirect applications (including extracted collagen peptides with smaller molecular weights, and collagen or gelatin with higher molecular weights used for hydrogels, and biological adhesives or glues) in the field of biomedicine in recent years. This review provides insights into the use of swim bladders as source of biomaterial; hence, it can aid biomedicine scholars by providing directions for advancements in this field.

Characterization, antimicrobial and cytotoxic activity of polymer blends based on chitosan and fish collagen

This study aims to produce, characterize, and assess the antimicrobial activity and cytotoxicity of polymer blends based on chitosan (CT) and fish collagen (COL) produced by different precipitation methods. Polymer blends were obtained in alkaline (NaOH), saline (NaCl), and alkaline/saline (NaOH/NaCl) solutions with different CT:COL concentration ratios (20:80, 50:50, and 80:20). The polymer blends were characterized by various physicochemical methods and subsequently evaluated in terms of their in vitro antimicrobial and cytotoxicity activity. In this study, the degree of chitosan deacetylation was 82%. The total hydroxyproline and collagen content in the fish matrix was 47.56 mg. g⁻¹ and 394.75 mg. g⁻¹, respectively. The highest yield was 44% and was obtained for a CT:COL (80:20) blend prepared by precipitation in NaOH. High concentrations of hydroxyproline and collagen in the blends were observed when NaOH precipitation was used. Microbiological analysis revealed that the strains used in this work were sensitive to the biomaterial; this sensitivity was dose-dependent and increased with increasing chitosan concentration in the products. The biocompatibility test showed that the blends did not reduce the viability of fibroblast cells after 48 h of culture. An analysis of the microbiological activity of the all-polymer blends showed a decrease in the values of minimal inhibitory concentration (MIC) and minimal bactericidal concentrations (MBC) for S. aureus and P. aeruginosa. The blends showed biocompatibility with NIH-3T3 murine fibroblast cells and demonstrated their potential for use in biomedical applications such as wound healing, implants, and scaffolds.

Different precipitation methods do not change the biological properties of polymer blends.

Gram-positive bacterias and Pseudomonas aeruginosa were sensitive to polymer blends.

The blends produced showed biocompatibility in NIH-3T3 murine fibroblast cells.

Comprehensive Assessment of Nile Tilapia Skin (Oreochromis niloticus) Collagen Hydrogels for Wound Dressings

Collagen plays an important role in the formation of extracellular matrix (ECM) and development/migration of cells and tissues. Here we report the preparation of collagen and collagen hydrogel from the skin of tilapia and an evaluation of their potential as a wound dressing for the treatment of refractory wounds. The acid-soluble collagen (ASC) and pepsin-soluble collagen (PSC) were extracted and characterized using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), differential scanning calorimetry (DSC), circular dichroism (CD) and Fourier transform infrared spectroscopy (FTIR) analysis. Both ASC and PSC belong to type I collagen and have a complete triple helix structure, but PSC shows lower molecular weight and thermal stability, and has the inherent low antigenicity. Therefore, PSC was selected to prepare biomedical hydrogels using its self-aggregating properties. Rheological characterization showed that the mechanical strength of the hydrogels increased as the PSC content increased. Scanning electron microscope (SEM) analysis indicated that hydrogels could form a regular network structure at a suitable PSC content. Cytotoxicity experiments confirmed that hydrogels with different PSC content showed no significant toxicity to fibroblasts. Skin repair experiments and pathological analysis showed that the collagen hydrogels wound dressing could significantly accelerate the healing of deep second-degree burn wounds and the generation of new skin appendages, which can be used for treatment of various refractory wounds.

The promising indicators of the thermal and mechanical properties of collagen from bass and tilapia: synergistic effects of hydroxyproline and cysteine

Hydroxyproline and cysteine have a synergistic effect on both the thermal and mechanical properties of fish collagen hydrogels.

Utilization of Chicken By-Products to Form Collagen Films

Chicken collagen casings could be an alternate source of collagen casings that are manufactured for sausages. The overall objective of this project was to extract chicken collagen from by-products of the broiler processing industries and to explore the possibility of making films. Chicken skin was washed, ground, and pretreated to remove the noncollagenous compounds. Collagen was extracted using acetic acid and pepsin. Solubilized collagen was salted-out and centrifuged at 20,000 ×g at 4°C for one hour. The precipitates were dissolved in 0.5 M acetic acid and dialyzed against 0.1 M acetic acid and distilled water before freeze-drying. Molecular weight, collagen solubility at different pH values, and NaCl concentrations were determined. TA-XT2 texture analyzer was used to characterize mechanical properties of collagen films. The highest collagen solubility was obtained at pH 2 and 2% NaCl. Hand-homogenized, nonfiltered, and conditioned samples had the highest hardness (3,262 g) and the least brittleness (30.5 mm). These results demonstrate that chicken collagen extracted from chicken by-products has the ability to form films and could be considered for making casings or be used in various other industries.

Effect of fish collagen modification on its thermal and rheological properties

This report describes the effects of different methods of silver carp collagen crosslinking on its properties, particularly their thermal, mechanical viscoelastic and biological behavior. Enzymatic analyses and determination of the degree of crosslinking showed the stabilizing effect of both dehydrothermal (DHT) and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC)/N-hydroxysuccinimide (NHS) treatments on fish collagen. The results of the thermal (DSC) measurements demonstrated that collagen crosslinked by EDC/NHS ensured a high thermal stability compared with collagen crosslinked dehydrothermally. The denaturation temperature (T(d)) of unmodified collagen samples increased from 77 to 80°C and 88°C for DHT- and EDC/NHS-treated collagen, respectively. The influence of DHT or EDC/NHS crosslinking on the viscoelastic behavior of fish collagen was elaborated by a shift of the tan δ(max) peak toward higher temperatures resulting in higher thermostability of the modified collagen samples.

Modification of fish skin collagen film and absorption property of tannic acid

Fish collagen is a biomacromolecule material and is usually used as a clarifying agent. However, fish collagen is not recyclable, and sedimentation usually occurs in the clarification process using fish collagen so that the filtration process is inevitable. This work aimed to provide a recyclable modified fish skin collagen film (MFCF) for adsorption of tannic acids. The collagen from channel catfish skin was extracted and used for preparation of the fish skin collagen film (FCF) and MFCF. The result indicated that the mechanical properties of MFCF were improved by addition of 2 ml/L glycerol, 6 ml/L polyvinyl alcohol (PVA) and 2 ml/L glutaraldehyde in 15 g/L collagen solution. As the most important property of adsorption material, the hydroscopicity of MFCF was only 54%, significantly lower than that of FCF (295%). Therefore, MFCF would not collapse in water. The infrared and thermal properties of MFCF were also investigated in this work. Results indicated that, in comparison to FCF, the physical and chemical properties of MFCF had been improved significantly. MFCF had higher shrink temperature (79.3 °C) and it did not collapse in distilled water at normal temperature. Furthermore, absorption and desorption properties of tannic acid were studied. MFCF showed good capability of absorption and desorption of tannic acid, which leaded to the suggestion that MFCF could have potential applications in adsorption material.