Acid-soluble Collagen Research Articles

Biohydrogel Based on Dynamic Covalent Bonds for Wound Healing Applications

In this work, a biohydrogel based on alginate and dynamic covalent B-O bonds, and derived composites, has been evaluated for wound healing applications. In particular, a phenylboronic acid–alginate (PBA-Alg) complex was synthesized by coupling 3-aminophenylboronic acid onto alginate, and used to prepare varied concentrations of hydrogels and silicate-based nanocomposites in PBS. The resulting hydrogels were characterized in terms of interfacial tension, moisture uptake and loss, interaction with fresh acid-soluble collagen, self-healing ability, effects on blood clotting and wound healing. The interfacial tension between the hydrogels and biorelevant fluids was low and moisture loss of 55–60% was evident without uptake from the environment. The components of the hydrogels and their mixtures with collagen were found to be compatible. These hydrogels showed efficient self-healing and thixotropic behavior, and the animals in the treatment groups displayed blood clotting times between 9.1 min and 10.7 min. In contrast, the composites showed much longer or shorter clotting times depending on the silicate content. A significant improvement in wound healing was observed in 3% w/v PBA-Alg formulations. Overall, the PBA-Alg hydrogels exhibit self-healing dynamic covalent interactions and may be useful in dressings for incision wounds.

Characterization of Acid-Soluble Collagen from Food Processing By-Products of Snakehead Fish (Channa striata)

The isolation of acid-soluble collagen (ASC) from by-products of snakehead fish (Channa striata), including skin and the mixture of skin and scale, has been investigated. The recovery yield of fish skin ASC (13.6%) was higher than ASC from fish skin and scale (12.09%). Both ASCs were identified as type I collagen and showed maximal solubility at pH 2. Collagen samples from the mixture of skin and scale had higher imino acid content (226 residues/1000 residues) and lower wavenumber in the amide I and amide III region (1642 and 1203 cm−1, respectively) than the fish skin ASC (the imino acid content was 220 residues/1000 residues and the wavenumber in the amide I and amide III were 1663 and 1206 cm−1, respectively. The difference scanning calorimeter (DSC) showed higher thermal stability in ASC from the mixture of skin and scale (Td of 35.78 °C) than fish skin ASC (34.21 °C). From the result, the denaturation temperature of ASC had a close relationship with the content of imino acid as well as with the degradation of α-helix in amide I and III. These results suggest that collagen could be obtained effectively from snakehead fish by-products and has potential as a realistic alternative to mammalian collagens.

Self-assembly characterization of tilapia skin collagen in simulated body fluid with different salt concentrations

The characteristics and self-assembly properties of acid soluble collagen (ASC) from tilapia skin in simulated body fluid (SBF) with different NaCl concentrations were investigated. When the concentration of NaCl was 65 mM, the lag time in the turbidity of collagen fibril formation was 2 min, which increased with the NaCl concentration. However, the collagen fibril forming degree decreased with the increasing NaCl concentration. Gel strength decreased when NaCl concentration increased from 135 mM to 160 mM. Rheological and differential scanning calorimetric analyses showed that the elasticity, melting temperature (Tm), and enthalpy (ΔH) of collagen fibril gel were promoted by the increasing NaCl concentration. Self-assembly could affect the conformation but did not affect denaturation of collagen. The dense fibril network structure of collagen gels was formed at SBF with high NaCl concentration. No obvious change was found in the d-periodicities of assembled fibrils. The amide I, II, and III bands in the Fourier transform infrared spectra of collagen gel moved from 1633, 1538, and 1236 cm−1, respectively, to 1628, 1532, and 1229 cm−1, respectively with the increasing NaCl concentration. These results exhibit that the ASC can self-assemble to form different collagen fibril gels in the SBF by adjusting the NaCl concentration.

Characterization and film-forming properties of acid soluble collagens from different by-products of loach (Misgurnus anguillicaudatus)

In this study, acid soluble collagens (ASCs) from different by-products of loach including skin, head, fins and bone were isolated, characterized and compared. As a result, the highest yield (on wet weight basis) was obtained for ASC from skin (ASC-S, 9.73%) compared with those from fins (ASC-F, 2.01%), head (ASC-H, 1.12%) and bone (ASC-B, 0.84%). By SDS-PAGE, these collagens were classified as type I collagens with slight difference of molecular weight. Glycine was the major amino acid in all ASCs with relatively high contents of alanine, hydroxyproline and proline. Fourier transform infrared spectroscopy indicated that triple helical structures of all ASCs were well preserved and scanning electron microscope exhibited fibrillary structure of ASC-B while sheet structure in others. Thermal stability of ASCs was determined by differential scanning calorimetry, rheometer and thermogravimetric (TG), respectively. It was concluded that all ASCs had different maximum transition (Tmax), denaturation (Td) and onset decomposition (To) temperatures. Besides, film-forming properties of ASCs from loach were also evaluated with ASC-F film showing strong tensile strength, best extensibility and barrier property compared with others, which suggested that ASCs from different by-products of loach had tremendous potential for applications in food packaging and coating in future.

Collagens made from giant salamander (Andrias davidianus) skin and their odorants

Two collagens were made from giant salamander (Andrias davidianus) skin by using acid and pepsin extraction methods. The yields of acid-soluble and pepsin-soluble collagens were 26.9 and 58.7%, respectively. The results of spectrum, electrophoresis and amino acid analysis showed that they were type 1 collagen with two α and one β peptides and high imino acid content. They had low solubility at a pH above 6 or salt concentration over 5%. The pepsin-soluble collagen had a better emulsion activity index. The odorants in raw skin and collagens were identified and evaluated using gas-chromatography mass-spectrometer and olfactometry methods and sensory analysis. The fishy and fatty off-odors in skin were not perceivable in the collagens. Sour, ammonia-like, and acrid off-odors were found in the collagens due to acid and enzymatic hydrolysis and protein degradation. The off-odor intensity of pepsin-soluble collagen was low. It could be considered a good and safe collagen material.

Characteristics of Acid Soluble Collagen from Catfish (Clarias Lazera) Skin

Characteristics of Acid Soluble Collagen from Catfish (Clarias Lazera) Skin

Evaluation of an electrochemically aligned collagen yarn for textile scaffold fabrication

Collagen is the major component of the extracellular matrix in human tissues and widely used in the fabrication of tissue engineered scaffolds for medical applications. However, these forms of collagen gels and films have limitations due to their inferior strength and mechanical performance and their relatively fast rate of degradation. A new form of continuous collagen yarn has recently been developed for potential usage in fabricating textile tissue engineering scaffolds. In this study, we prepared the continuous electrochemical aligned collagen yarns from acid-soluble collagen that was extracted from rat tail tendons (RTTs) using 0.25 M acetic acid. Sodium dodecyl sulfate polyacrylamide gel electrophoresis and Fourier transform infrared spectroscopy confirmed that the major component of the extracted collagen contained alpha 1 and alpha 2 chains and the triple helix structure of Type 1 collagen. The collagen solution was processed to monofilament yarns in continuous lengths by using a rotating electrode electrochemical compaction device. Exposing the non-crosslinked collagen yarns and the collagen yarns crosslinked with 1-ethyl-3-(-3-dimethyl-aminopropyl) carbodiimide hydrochloride to normal physiological hydrolytic degradation conditions showed that both yarns were able to maintain their tensile strength during the first 6 weeks of the study. Cardiosphere-derived cells showed significantly enhanced attachment and proliferation on the collagen yarns compared to synthetic polylactic acid filaments. Moreover, the cells were fully spread and covered the surface of the collagen yarns, which confirmed the superiority of collagen in terms of promoting cellular adhesion. The results of this work indicated that the aligned RTT collagen yarns are favorable for fabricating biotextile scaffolds and are encouraging for further studies of various textile structure for different tissue engineering applications.

Acid and Pepsin Soluble Collagens from Skin By-product of Red-bellied Pacu (Piaractus brachypomus): Extraction and Comparative Characterizations Towards Finding Substitute to Bovine and Porcine Collagen

ABSTRACT This investigation focused on the sustainable valorization of red-bellied pacu (RBP) skin towards finding an alternative to bovine and porcine collagen. Acid-soluble collagen (ASC, 45.8 ± 0.7%) and pepsin soluble collagen (PSC, 57.8 ± 1.9%) were successfully extracted from RBP skin and comparatively elucidated their characteristics and in-vitro fibril-forming potential. The extracted collagens were characterized as type I collagen and confirmed the well-preserved triple-helical configuration by sodium dodecyl sulphate polyacrylamide gel electrophoresis and Fourier transform-infrared spectroscopy analysis. Both ASC and PSC exhibited relatively better thermo-stability, and the denaturation temperatures were found to be 35.5–35.29 °C by differential scanning calorimetry analysis. Both collagens displayed higher (p ≤ 0.05) solubility at low NaCl concentrations. The extracted ASC and PSC showed the same degree of fibril-forming capacities and confirmed well-defined fibril morphologies. Overall, the results showed the possibilities of effectively exploring RBP skin as a potential alternative source for realistic and safe collagen for food, nutrition, pharmaceutical, and other applications.

Extraction Methods, Characterization and Biomedical Applications of Collagen: a Review

It is difficult to develop a standard extraction method for all types of collagen from different tissues due to the extreme diversity of collagen types. Some procedures are based on the isolation of acid, pepsin, and enzymatic soluble collagen, showing certain advantages and disadvantages. Other methods were also optimized to partially purify collagen and extract it easier than the methods currently used. Indeed, this review describes some advantages and disadvantages of these isolation methods. Moreover, major biomedical applications of collagen were reported. Given the great importance of biocompatible matrices in tissue engineering, the availability of native collagen should be investigated by refining the collagen extraction procedure.

Collagen-Based Thiol-Norbornene Photoclick Bio-Ink with Excellent Bioactivity and Printability.

As the essential foundation of bioprinting technology, cell-laden bio-ink is confronted with the inevitable contradiction between printability and bioactivity. For example, type I collagen has been widely applied for its excellent biocompatibility; however, its relatively low self-assembly speed restricts the performance in high-precision bioprinting of cell-laden structures. In this study, we synthesize norbornene-functionalized neutral soluble collagen (NorCol) by the reaction of acid-soluble collagen (Col) and carbic anhydride in the aqueous phase. NorCol retains collagen triple-helical conformation and can be quickly orthogonally cross-linked to build a cell-laden hydrogel via a cell-friendly thiol-ene photoclick reaction. Moreover, the additional carboxyl groups produced in the reaction of carbic anhydride and collagen obviously improve the solubility of NorCol in neutral buffer and miscibility of NorCol with other polymers such as alginate and gelatin. It enables hybrid bio-ink to respond to multiple stimuli, resulting in continuous cross-linked NorCol networks in hybrid hydrogels. For the first time, the collagen with a triple helix structure and gelatin can be mixed and printed, keeping the integrity of the printed construct after gelatin's dissolution. The molecular interaction among giant collagen molecules allows NorCol hydrogel formation at a low concentration, which leads to excellent cell spreading, migration, and proliferation. These properties give NorCol flexible formability and excellent biocompatibility in temperature-, ion-, and photo-based bioprinting. We speculate that NorCol is a promising bio-ink for emerging demands in tissue engineering, regenerative medicine, and personalized therapeutics.

Distinctive characteristics of collagen and gelatin extracted from Dosidicus gigas skin

SummarySquid skin, often discarded as processing by‐product, is a good resource of collagen/gelatin. In this study, acid soluble collagen (ASC), pepsin soluble collagen (PSC) and water soluble gelatin (WSG) were extracted from squid (Dosidicus gigas) skin and physicochemically examined. The lowest yield of 33.5% was obtained for ASC extracted at 4 °C, and the addition of pepsin increased the collagen yield by around 35.0% (PSC). The highest yield of 81.9% (WSG) was achieved by thermal extraction at 60 °C. A low temperature can largely retain the native helix structures of ASC and PSC, contrariwise, thermal treatment converted collagen into gelatin with unordered and renatured structures. The proline and hydroxyproline contents of ASC, PSC and WSG were 183/1000 residues, 194/1000 residues and 175/1000 residues, respectively. In addition, WSG showed a denaturation temperature at 80.7 °C which was much higher than that of ASC (24.2 °C) and PSC (26.2 °C), while a significant lower resistance towards enzymatic digestion.

Collagen isolation and characterization from Sardinella longiceps.

Objective:Collagen is a fibrous protein that is primarily used in the pharmaceutical and biomedical industries. This study isolates and characterizes type-1 collagen from Sardine longiceps (scales, skin, and muscle).Materials and Methods:Collagen was isolated from S. longiceps using two methods: acid-solubilized collagen and pepsin-solubilized collagen. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE) was used to estimate the molecular weight of isolated collagen. Ultraviolet (UV)-visible spectrophotometry analysis was used to confirm the collagen extracted (type-I collagen). The functional groups of isolated collagens were identified using fourier transform infrared (FTIR) analysis. The X-ray diffraction (XRD) technique was used to investigate the crystallinity of isolated collagen. The high-pressure liquid chromatography (HPLC) technique was used to study the amino acid composition.Results:SDS–PAGE of S. longiceps revealed molecular weights ranging from 116 kDa for α-2 to 97 kDa for α-1. UV-visible spectra showed an absorbance value below 300 nm, and the results confirmed type-I collagen. FTIR showed major functional groups like amide A, B, I, II, and III. XRD determined the crystallinity of isolated collagen. The HPLC results showed the presence of higher glycine content, followed by proline and hydroxyl proline in the extracted collagen.Conclusion:The overall study confirmed that fish waste materials (scales, skin, and muscles) could be used as an alternative source for collagen.

The potency of spice extracts in fish skin collagen production

Spices can be used as an alternative washing agent in fish collagen production, replacing organic materials' commonly used washing agent. Many Asians, including Indonesian traditional culinary use spices to remove the fishy odor. Therefore this research was conducted to obtain a suitable spice used as a washing agent in fish collagen production. Ginger, galangal, lemongrass, bay leaves, lime leaves, and pandan leaves were used as the tested spices in the form of 5% liquid extract in water. The ANOVA and LSD test on fishy odor test data showed that most respondents preferred Pangasius skin soaked in galangal liquid extract and had no significant difference in odor compared to the control (ethanol). Pangasius skin soaked in galangal extract had the total protein and ash content lower than control, while the total fat and water content were higher. Soaking in galangal extract also made Pangasius skin have a higher degree in swelling and total protein content in its acid-soluble collagen (ASC) extract than in control. The higher value of the two latter parameters was also found in the descaling Tuna skin soaked in galangal extract.

Study of the thermodynamics and conformational changes of collagen molecules upon self-assembly

The emphasis on mechanism of collagen self-assembly shows great significance for development of collagen-based materials with targeted attributes. Here, combination of isothermal titration calorimetry (ITC) dilution experiments, circular dichroism (CD) and FTIR measurements were employed to investigate the thermodynamic differences and corresponding mechanisms associated with self-assembly of acid-soluble collagen (ASC) and pepsin-soluble collagen (PSC). Firstly, the microrheology measurements of ASC and PSC under the different temperatures (20 °C, 25 °C, 30 °C and 37 °C) had confirmed the temperature induced collagen aggregation. The several thermodynamic parameters (Gibbs free energy change, enthalpy change and entropy change) and the critical mass concentration (CMC) of ASC and PSC, obtained by ITC dilution experiments, decreased with the rising temperatures. The magnitudes of negative Gibbs free energy changes were always higher for ASC than that of PSC, indicating former was more energetically favorable. Besides, the self-assembly of both two collagens were driven by hydrophobic interactions, as evidenced by a negative heat capacity value (ΔCp,mic<0). Specifically, the hydrophobic effects improved due to the transformation of PPII into β-sheet conformations upon collagen self-assembly, as supported by differential CD spectra and FT-IR measurements. Overall, ASC had a higher PPII population than PSC at most temperatures, which may elaborate the thermodynamic differences of two collagens in terms of secondary structure.

Isolation and characterization of acid and pepsin soluble collagen extracted from sharpnose stingray (Dasyatis zugei) skin

This study aimed to isolate and characterize the acid soluble collagen (ASC) and pepsin soluble collagen (PSC) from the skin of the sharpnose stingray (Dasyatis zugei). Isolated ASC and PSC were subjected to chemical and physical characterizations. The yield of PSC (34.84±1.26%) was significantly higher than that of ASC (20.48±4.41%) (p&lt;0.05). There were no significant differences between ASC and PSC in terms of chemical composition (p&gt;0.05). Both ASC and PSC were thermally stable at high temperatures, with denaturation temperatures of 24.1°C and 25.2°C, respectively, and maximum temperatures of 31.94±0.13°C and 31.79±0.23°C, respectively. Fourier transform infrared (FTIR) investigations showed the presence of triple helical structure with strong hydrogen bonding in both ASC and PSC. Meanwhile, both collagens were highly solubilized at acidic pH but at different optimal pH. The surface morphologies of ASC and PSC were loose and possessed slender, less uniform and irregular fibrous network structures with large and irregular pores observed between the fibrils. This finding showed that the alternative source of marine collagen possesses good physicochemical properties which highly potential for nutraceutical, pharmaceutical or cosmeceutical application.

Characteristics and Functional Properties of collagen extracted from Nile tilapia (Oreochromis niloticus) skin

: Tilapia skin might be used as a new source of collagen, therefore collagen extracted from Nile tilapia skin can be utilized as food products because of its good functional properties. Two extraction methods were used to obtain acid-soluble collagen (ASC) and pepsin-soluble collagen (PSC) from Nile tilapia skin. In this study, collagen was characterized in terms of FT-IR Spectrum, amino acid analysis, SDS-PAGE and Thermal denaturation temperatures (Td). Also, some major functional properties including solubility, oil and water absorption, emulsifying activity and stability, foaming ability, foam stability, and gelation properties were determined. The results showed that the yields of ASC and PSC were 4.30% and 1.84 % (on a wet weight basis), respectively. Amino acid composition analysis indicated that the imino acid content of ASC and PSC were found to be 172.10 and 164.18 residues per 1000 residues, respectively. SDS-PAGE results indicated that ASC and PSC were type I collagen. The FTIR Spectrum confirmed that the presence of a triple-helical structure characteristic of ASC and PSC. The denaturation temperature of ASC and PSC were 26⁰C and 25⁰C respectively. The solubility of ASC and PSC were highly solubilized in the pH range of 2–3. ASC and PSC had good water and oil absorption capacity. Gelation studies revealed that ASC and PSC have good gelation properties. Consequently, Nile tilapia skin could be used as a good source to extract ASC and PSC which can be used to add high value in the food industries.

Extraction and Characterization of Collagen from Elasmobranch Byproducts for Potential Biomaterial Use.

With the worldwide increase of fisheries, fish wastes have had a similar increase, alternatively they can be seen as a source of novel substances for the improvement of society’s wellbeing. Elasmobranchs are a subclass fished in high amounts, with some species being mainly bycatch. They possess an endoskeleton composed mainly by cartilage, from which chondroitin sulfate is currently obtained. Their use as a viable source for extraction of type II collagen has been hypothesized with the envisaging of a biomedical application, namely in biomaterials production. In the present work, raw cartilage from shark (Prionace glauca) and ray (Zeachara chilensis and Bathyraja brachyurops) was obtained from a fish processing company and submitted to acidic and enzymatic extractions, to produce acid-soluble collagen (ASC) and pepsin-soluble collagen (PSC). From all the extractions, P. glauca PSC had the highest yield (3.5%), followed by ray ASC (0.92%), ray PSC (0.50%), and P. glauca ASC (0.15%). All the extracts showed similar properties, with the SDS-PAGE profiles being compatible with the presence of both type I and type II collagens. Moreover, the collagen extracts exhibited the competence to maintain their conformation at human basal temperature, presenting a denaturation temperature higher than 37 °C. Hydrogels were produced using P. glauca PSC combined with shark chondroitin sulfate, with the objective of mimicking the human cartilage extracellular matrix. These hydrogels were cohesive and structurally-stable at 37 °C, with rheological measurements exhibiting a conformation of an elastic solid when submitted to shear strain with a frequency up to 4 Hz. This work revealed a sustainable strategy for the valorization of fisheries’ by-products, within the concept of a circular economy, consisting of the use of P. glauca, Z. chilensis, and B. brachyurops cartilage for the extraction of collagen, which would be further employed in the development of hydrogels as a proof of concept of its biotechnological potential, ultimately envisaging its use in marine biomaterials to regenerate damaged cartilaginous tissues.

Extractability and physicochemical properties of cobia ( Rachycentron canadum ) skin collagen as influenced by lactic acid concentration

The present research aims to elucidate the effect of lactic acid concentration on the extractability and physicochemical properties of cobia (Rachycentron canadum) skin collagen. The cobia skin acid-soluble collagen (ASC) was isolated using different concentrations of lactic acid (0.5 M and 1.0 M) and characterized on its extractability and physicochemical properties. The extract using 0.5 M lactic acid gives a higher yield compared to using 1.0 M lactic acid. The moisture, protein, fat, and ash content of cobia skin ASC extracted using 0.5 M was higher than extracted using1.0 M lactic acid. The functional group present in both extracts was amide A, amide I, and amide III. Both extracts at different lactic acid concentrations showed decreasing on relative viscosity with temperature increased. Thus, different extractability and physicochemical properties of cobia skin ASC extracts exhibits based on the lactic acid concentration and it would produce collagen with multi potential application. Practical applications The best way to minimize the environmental contaminations from fish processing industrial waste and provide the economic value to waste materials is collagen production. Collagen prepared from fish skin can utilize in various purposes as biopolymer. Extraction of collagen from a chemical method by utilizing organic acid like acetic acid, chloroacetic acid, citric acid, lactic acid, or inorganic acid like hydrochloric acid is more suitable due to low-cost effective which compared to enzyme like pepsin. The present study focused on the utilization of lactic acid at different concentration produces collagen with multipotential application with extractability and physicochemical properties.

Relevance of collagen solubility and gelatinolytic proteinase activity for texture softening in chilled grass carp (Ctenopharyngodon idellus) fillets

SummaryThe aim of the present study was to investigate the underlying mechanisms of softening texture in chilled grass carp filletsunderpinning collagen solubility, gelatinolytic proteinase activity and physicochemical parameters. Acid‐soluble collagen (ASC) and heat soluble collagen (HSC) increased markedly, while a significant decline was detected in total collagen and insoluble collagen (ISC) during the first 3 days of storage, coinciding with a loss of shear force and water‐holding capacity (WHC) (P &lt; 0.05). Moreover, the activity of gelatinolytic proteinases was gradually activated and reached the peak at day 3 (P &lt; 0.05). Pearson coefficient analysis showed that gelatinolytic proteinase activity revealed a significant correlation with collagen solubility. Total collagen, ASC, ISC and HSC were significantly correlated with shear force and WHC. Our study clarified that the increase of collagen solubility by gelatinolytic proteinases played an important role for texture softening in the early stage of chilled grass carp fillets.

SUITABILITY OF ACID-SOLUBLE AND ACID-INSOLUBLE LEATHER FRACTIONS IN RADIOCARBON DATING

ABSTRACTLeather has been produced by a variety of methods throughout human history, providing researchers unique insight into multiple facets of social and economic life in the past. Archaeologically recovered leather is often fragile and poorly preserved, leading to the use of various conservation and restoration efforts that may include the application of fats, oils, or waxes. Such additives introduce exogenous carbon to the leather, contaminating the specimen. These contaminants, in addition to those accumulated during interment, must be removed through chemical pretreatment prior to radiocarbon (14C) dating to ensure accurate dating. DirectAMS utilizes organic solvents, acid-base-acid (ABA) and gelatinization for all leather samples. Collagen yield from leather samples is variable due to the method of production and the quality of preservation. However, evaluating the acid-soluble collagen fraction, when available, provides the most accurate 14C dates for leather samples. In instances where gelatinization does not yield sufficient material, the resulting acid-insoluble fraction may be dated. Here we examine the effectiveness of the combined organic solvent and ABA pretreatment with gelatinization for leather samples, as well as the suitability of the acid-insoluble fraction for 14C dating.