Acid-soluble Collagen Research Articles

Valorizing sardine scales: a circular approach to sustainable collagen for cosmetics and nutrition applications

Background and ObjectiveIn recent years, the consumption of fish products has led to a worrying trend where approximately two-thirds of the total amount of fish is discarded as waste. At the same time, scientific interest in exploring natural collagen sources for cosmetics and dietary supplements has increased. This study explores the potential of valorizing sardine scales (Sardina pilchardus), a by-product of the canning industry, through the extraction of collagen for potential use in dermocosmetic formulations and food supplements.MethodsCollagen from sardine scales was obtained though acid and enzymatic extraction. The collagen extracts were characterized by UV-Vis, FTIR spectroscopy, SDS-PAGE, powder X-ray diffraction (PXRD) and scanning electron microscopy (SEM). The collagen was hydrolysed with papain to small peptides. Subsequently, the biological activities of acid-soluble collagen as well as the collagen peptides in terms of antioxidant and antimicrobial activity were evaluated. Furthermore, the capacity of collagen peptides to permeate the intestinal barrier, simulated with caco-2 cells, was evaluated.ResultsPurified collagen extracts were obtained from sardine scales, with enzymatic extraction method having a yield three times higher than the acid method. The SDS-PAGE analysis confirmed the extraction of type I collagen as well as its hydrolysis into small fragments (25–12 kDa). In terms of biological activities, collagen and collagen peptides have not demonstrated antimicrobial activity. However, regarding antioxidant activity, collagen peptides showed three times more capacity compared to non-hydrolyzed collagen. Meanwhile, in 6 h, about 6.37% of collagen peptides could permeate the intestinal barrier.ConclusionThis work represents a continuous effort to advance our understanding and utilization of Portuguese marine waste resources, with focus on the valorization of sardine co-products for the development of food supplement or cosmetic formulations, contributing to the sustainable evolution of the circular blue economy.

Chemical Composition of Acid Soluble Collagen (ASC) Isolated from Indonesia Local “Kacang” Goat Skin (<i>Capra aegagrus hocus</i>)

Collagen from the local "Kacang” goat skin is a natural raw material in the halal food industry in Indonesia. This study aims to isolate acid-soluble collagen (ASC) from “Kacang” goat skin and characterize its chemical properties. The collagen was derived from one-year-old goat skin and cured in acid condition for 48 hours at 4°C to eliminate meats, fat, and hair. The cleaned skins were treated at 1:10 (w/v) of 0.1 M NaOH for 0, 24, and 48 h at 4°C. It was then neutralized in distilled water and extracted with 0.5 M acetic acid at a 1:10 (w/v) ratio for 24, 48, and 72 h at 4°C. The yield of ASC was 21%, characterized by chemical composition, soluble protein, differential scanning calorimeter (DSC), and protein molecular weight. The chemical composition of ASC was 11.15% (moisture), 9.04% (protein), 0.98% (fat), and 0.052% (ash). ASC has the highest collagen solubility in NaCl 5% at pH 2. ASC also has thermal stability with a low profile pattern of molecular weight. In conclusion, “Kacang” goat skin from Indonesia might be used to make a value-added product because it has a high moisture content and low fat level.

Aurelia aurita jellyfish collagen: Recovery properties

Wound and burn healing is a complex physiological process that can be facilitated by medications based on marine collagen. In this regard, biomass of the Aurelia aurita jellyfish is a promising alternative source of medical collagen. As the global incidence of burns and wounds continues to grow, new healing methods have become a relevant area of medical science. This study featured acetic acid as a means of marine collagen extraction from A. aurita biomass. The physical and chemical properties of jellyfish collagen were determined gravimetrically and included such indicators as water solubility and water holding capacity. The molecular weight was defined by gel electrophoresis. The spectral studies relied on the method of UV spectroscopy. The regenerative experiments included such parameters as cytotoxicity, antioxidant properties, adhesion, and wound healing rate, as well as a quantitative PCR analysis. The optimal conditions for maximal collagen yield were as follows: 0.5 M acetic acid and 48 h extraction time. However, the collagen yield was very low (≤ 0.0185%). The high water holding capacity showed good prospects for A. aurita collagen to be used as hemostatic sponge. The acid-soluble collagen sample had a molecular weight of 100–115 kDa, which made it possible to classify it as type I. A. aurita jellyfish collagen revealed no cytotoxic properties; it had no effect on adhesion, migration, and proliferation of keratinocytes, neither did it affect the expression of cell differentiation markers. The wound healing model proved that the marine collagen had regenerative properties as it was able to increase the wound healing rate by 24.5%. Therefore, collagen extracted from the biomass of A. aurita jellyfish d emonstrated good p rospects for cosmetology and regenerative medicine.

Photocatalytic degradation of phenol and polycyclic aromatic hydrocarbons in water by novel acid soluble collagen-polyvinylpyrrolidone polymer embedded in Nitrogen-TiO2

Herein, we have synthesized acid-soluble collagen (ASC), polyvinylpyrrolidone (PVP), and nitrogen-doped titanium dioxide to form a novel hybrid photocatalyst nanocomposite (N-TiO2/ASC-PVP). The results of XRD, SEM and TEM revealed that the as-synthesized photocatalyst was composed of spheroidal particles, which were smaller than undoped TiO2.XPS analysis revealed that N was effectively incorporated into the lattice of TiO2 through substituting oxygen atoms, and N might coexist in the form of substitutional N (O–Ti–N) and interstitial N (TiON). The N-TiO2/ASC-PVP composite calcined at 200 and 400 °C exhibited high photocatalytic degradation rates for phenol, naphthalene (Nap), fluoranthene (Flu), phenanthrene (Phe), pyrene (Pyr), benz[a]anthracene (BaA), and anthracene (Ana), achieving a 98.6 % removal rate within 120 min at a dosage of 10 mg/L. The enhanced visible light photocatalytic activity was mainly attributed to the smaller crystal size, more surface hydroxyl groups, stronger light absorption in visible region and narrower band gap energy. This innovative hybrid photocatalyst holds immense potential for applications in materials science and nanotechnology, promising to revolutionize various industries.

Characteristics and properties of co-precipitated protein and film based on Bambara groundnut protein isolate and fish skin acid-soluble collagen

Co-precipitated protein (CPP) from Bambara groundnut protein isolate (BGPI) and fish skin acid-soluble collagen (ASC) at different BGPI/ASC ratios (100:0, 75:25, 50:50, 25:75 and 0:100 (v/v)) were prepared and characterized. CPP of BGPI/ASC at ratio of 75:25 had higher solubility at acidic and alkaline pHs, compared to other CPP samples. All CPPs had good emulsifying properties. Based on protein patterns, the combination of major bands from BGPI and ASC in the resulting CPP sample was observed. CPP with BGPI/ASC at ratio of 75:25 showed higher surface hydrophobicity than those of other CPP samples. When the films from CPPs were fabricated, similar tensile strength (p > 0.05) was observed, regardless of BGPI/ASC ratios. Nevertheless, film from CPP with BGPI/ASC ratio of 25:75 had higher elongation at break along with lower water vapor permeability (p < 0.05), compared to other CPP films. All CPP films had bright-yellowish color. Increasing ASC ratio augmented (p < 0.05) light transmission of resulting CPP films. FTIR spectra revealed that all CPP films had the similar pattern and functional groups. Therefore, the co-precipitated BGPI and ASC at appropriate ratio could improve properties of resulting proteins, especially for film forming ability.

Chitosan-collagen biopolymer biofilm derived from cephalopod gladius; Evaluation of osteogenesis, angiogenesis and wound healing for tissue engineering application

Chitosan (Ch) and acid-soluble collagen (ASC) from Doryteuthis singhalensis gladius were isolated to test their osteogenic, angiogenic, and wound healing capabilities in male Wistar rats. The results of the study showed that the ASC yield was 18.58 %, the total protein content was 86.43 % ± 0.18 %, and the amino acid composition was as follows: glycine, 15.68 %; proline, 13.84 %. A, B, I, II, and III show FT-IR amide regional bands at 3392, 2959, 1652, 1471, and 1237 cm−1 respectively. The electrophoretic pattern of ASC validated its molecular weights of 105 kDa and 96 kDa. The 1H NMR spectra showed pure singles at 1.99 ppm, and the UV–Vis spectrum showed a particular absorbance between 238 and 220 nm. The DSC showed two endothermic peaks: one with an To value of 119.72 °C and TP of 126.28 °C, and the other with 147.42 °C and 148.47 °C. Initially, we fabricated Ch and ASC biofilms at an 8.5:1.5 ratio for tissue engineering applications. A cellular-level study demonstrated good biocompatibility and enhanced osteoblastic differentiation of collagen chitosan films (CChF). Additionally, the biofilm exhibited increased angiogenic potency, as observed in the chick embryo chorioallantoic membrane (CAM) assay. The experimental animal model demonstrated that in wound healing, the CChF treated rats (95.75 ± 2.28 %) had a greater decrease in the diameter of the wound than the control rats (22.25 ± 2.45 %), followed by the CF (collagen film) treated rats (63.25 ± 2.08 %) and ChF (chitosan film) (52.67 ± 1.58 %). Rats treated with CChF had 48.82 ± 1.25 mg/g of hydroxyproline in NFGT and 75.25 ± 1.56 mg/g of overall protein. The higher hydroxyproline levels in the CChF-treated groups corroborated these histopathological findings. These results imply that by promoting the development of scars, inflammation, and proliferation, CChF accelerates the healing process.

Insight into the self-assembly process, microrheological properties and microstructure of acid-soluble collagen from lamb skin under different environmental conditions

The self-assembly behavior of collagen under the regulation of the external environment is important for the construction of collagen-based materials. In this study, the effects of temperature, pH, and ion concentration on the self-assembly property, microrheology, and microstructure of acid-soluble collagen (ASC) extracted from lamb skin were investigated. The kinetics of ASC self-assembly under different environmental conditions was captured by monitoring the turbidity over time. The results showed that the ASC assembly process was accelerated by temperature increase in the range of 25–37 °C, and the self-assembly was unfavorable when the temperature exceeded 37 °C. The pH closed to the isoelectric point of ASC was conducive to assembly, and appropriate ion concentration increased the assembly rate of ASC. The microrheology reflected the influence of environmental conditions on the assembly process through the changes in the elastic and solid-liquid transition points of the solution system, and the results were consistent with the conventional turbidimetry method. Scanning electron microscopy showed that ASC formed fibril structures with different diameters in different environments. In addition, infrared spectroscopy showed the changes of secondary structure of ASC during the assembly process. The amino acid composition, UV spectrum, secondary structure, and morphology of ASC were characterized. The above results provide a foundation for the construction of controllable ASC self-assemblies from lambskins.

Acid-soluble collagen (ASC) hydrolysate from Javanese goat (Capra aegagrus hocus) skin: effect of pepsin hydrolysis and antioxidant activity

Abstract Javanese goat (Capra aegagrus hocus) is an animal species which have many populations in Indonesia and it is used because more selective in feed, especially Leguminosae and seeds which of rich in collagen. The study aims to determine the impact of hydrolysis time and antioxidant activities on the extraction of skin Javanese goats using the acid-soluble collagen (ASC) method. The ASC used in this investigation was taken from another study and hydrolyzed with pepsin throughout the course of 0, 30, 60, 90, and 120 minutes of incubation. The success of the hydrolysis process can be shown by the percent degree of hydrolysis. Methods are used to determine the percent degree of hydrolysis of the TCA method. Results showed that hydrolyzing for 60 min yields the highest total soluble collagen of ASC, with a value of 0.77 mg/ml. Finally, the ASC which is hydrolysis use pepsin for 60 min has a degree of hydrolysis, and total soluble collagen is the highest. The protein molecular weight of ASC which is the hydrolysis of 60 min is smaller than before hydrolysis and it has radical scavenging activity of 56.42% ± 1.45. So far, ASC from Javanese goat (Capra aegagrus hocus) has been hydrolyzed in this study has high antioxidant activity and can be recommended as a substitute for functional food.

Exploring collagen diversity in the bone of mesopotamian catfish (Silurus triostegus, Heckel, 1843)

Collagen, a pivotal extracellular matrix biomolecule ubiquitous in connective tissues, drew substantial attention due to its widespread presence, notably in skin and bone. This pioneering study delves into the extraction, characterization, and amino acid profiling of acid-soluble collagens (ASC) obtained from the bone (ASC-B) of the Mesopotamian catfish, Silurus triostegus, (Heckel, 1843). Notably, this research marks the inaugural exploration of this species as a collagen source. Fourier transform infrared spectroscopy (FTIR) confirmed the integrated and native nature of both collagens, while X-ray diffraction (XRD) results indicated the preservation of helical structures in both skin and bone collagens. UV-Vis spectra highlighted prominent absorptions at 230 nm. SEM studies revealed the porous and fibrous structure of ACS-B Collectively considering UV–Vis and FTIR results alongside the amino acid composition, the extracted collagens were characterized as type I collagen. The collagen isolated from the catfish emerges as a potential alternative source of vertebrate collagens with prospective applications in diverse industries, including diet, medical, and pharmaceutical sectors.

Sustainable Collagen Film Preparation with Tannins Extracted from Moroccan Pomegranate Byproduct Varieties: Thermal, Structural, and Nanoscaled Studies.

Recently, obtaining collagen films using a cross-linking technique has been a successful strategy. The current investigation used six cross-linker extracts (CE) from six different pomegranate varieties' byproducts to make and characterize collagen-tannin films using acid-soluble collagen (SC). The polymeric film has a yellow hue after CE incorporation. Fourier transform infrared spectroscopy assessed the impact of CE and its successful interaction within the matrix. The shifts verify different interactions between extracts and collagen functional groups, where they likely form new hydrogen bonds, retaining their helix structure without damaging the matrix. Scanning electron microscopy was used to analyze the morphology and fiber size. The average diameter of the fibers was found to be about 3.64 μm. Thermal behaviors (denaturation and degradation) were investigated by thermogravimetric analysis. The weight losses of cross-linked films increased by around 20% compared to non-cross-linked ones. This phenomenon was explained by the absence of telopeptide sections in the collagen helical structure, typically reinforced by lysine and hydroxylysine covalent linkages. Nanoscaled observations were also accomplished using transmission electron microscopy (TEM) on SC and SC-CE. The TEM analysis confirmed the CE polymerization degree effect on the cross-linking density via the overlap sequences, ranging up to 32.38 ± 2.37 nm on the fibril. The prepared biodegradable collagen-tannin film showed higher cross-linking density, which is expected to improve the biomaterial applications of collagen films while exploiting the underrated pomegranate byproducts.

Characterization of acid-soluble collagen (ASC) derived from walleye pollock and silver carp skin and comparison them with the collagen from pig and duck skin

The acid-soluble collagens (ASC) extracted from the skins of walleye pollock and silver carp were compared with ASCs from skins of duck and pig in physicochemical properties. The dry weight extraction rates of ASCs from walleye pollock and silver carp were 14.10 % and 10.30 %, which were significantly higher than those of pig and duck (4.53 % and 3.14 %). It was found that the ASCs from skins of pig, walleye pollock and silver carp were all type I collagen with intact triple helix structure, while ASC from duck skin was a mixture of type I and type II collagen.The PI of the four ASCs was in the weakly acidic range (5.49–6.84), but ASCs from two fish skins were less thermally stable than that from pig and duck. The dynamic frequency scanning showed that collagen from porcine skin always maintained elastic behavior, while the other three ASCs changed from viscous behavior to elastic behavior with the increasing of frequency. The collagen from two fish skins had a less dense microstructure. The high extraction rate proved that two fish skins were high-quality raw materials for collagen, and the differences in physicochemical properties allowed fish skin collagen to have different applications than terrestrial animal collagen.

Stem-Cell-Regenerative and Protective Effects of Squid (Symplectoteuthis oualaniensis) Skin Collagen Peptides against H2O2-Induced Fibroblast Injury.

Recently, there has been a growing interest in collagen peptides derived from marine sources for their notable ability to protect skin cells against apoptosis induced by oxidants. Therefore, the current study aimed to investigate the fundamental properties of collagen peptides, including their physicochemical, thermal, structural, stem-cell-regenerative, and skin-cell-protective effects, in comparison to commercial collagen peptides. The acid-soluble (ASC) and pepsin-soluble (PSC) collagens exhibited three distinct bands on SDS-PAGE, namely α (α1 and α2), β, and γ chains, confirming a type I pattern. The thermal profiles obtained from TG and DSC analyses confirmed the denaturation of PSC and ASC at temperatures ranging from 51.94 to 56.4 °C and from 52.07 to 56.53 °C, respectively. The purified collagen peptides were analyzed using SDS-PAGE and MALDI-TOF mass spectrometry, revealing a mass range of 900-15,000 Da. Furthermore, the de novo peptide sequence analysis confirmed the presence of the Gly-X-Y repeating sequence in collagen peptides. Collagen peptide treatments significantly enhanced HFF-1 cell proliferation and migration compared to the control group. ELISA results confirmed the potential interactions between collagen peptides and HFF-1 cells through α2β1, α10β1, and α11β1 integrin receptors. Notably, collagen peptide treatment effectively restored the proliferation of HFF-1 cells damaged by H2O2. Consequently, the advantageous characteristics of squid skin collagen peptides highlight their promising role in regenerative medicine.

Effect of core–sheath bi‐polymeric scaffolds fabricated from acid‐soluble collagen and poly(lactic acid) derivatives on wound healing

AbstractThe core–sheath bi‐polymeric scaffold has been proven as an encouraging material based on the requirement of scaffolds. This study aims to prepare electrospun core–sheath scaffolds by using acid‐soluble collagen (ASC) as core material and poly(lactic acid) (PLA) or PLA‐g‐VAc as sheath material to get the most in combination from a hydrophilic and a hydrophobic polymer. ASC is extracted from waste Tilapia fish skin conserving the triple helix structure of the α1 (130 kDa) chain, and a α2 (120 kDa) chain cross‐linked with the β (280 kDa) chain confirmed by amino acid profile, sodium dodecyl sulphate‐polyacrylamide gel electrophoresis. PLA‐g‐VAc is prepared by grafting vinyl acetate (VAc) onto the PLA chain using benzoyl peroxide as the initiator. FT‐IR, 1H NMR, and 13C NMR of PLA‐g‐VAc reveal that grafting occurs between the double bond of VAc and the methine group of PLA. The morphology of the scaffolds is determined by the field emission scanning electron microscope. FT‐IR, thermogravimetric analysis, differential scanning calorimetry, XRD, and water contact angle measurements are used for further characterization of scaffolds. In vivo, cytotoxicity analysis on the Vero cell line exposes that scaffolds are biocompatible. Application of scaffolds to the surgically produced wounding of skin in a rat model followed by histological assay indicates the enhanced properties of core–sheath scaffolds rather than the single polymeric scaffolds.

In vitro chronic wound healing using collagen and plant extract along with zinc nanoparticles

INTRODUCTION: While the use of zinc nanoparticles (ZnNPs) as an antibacterial agent in the biomedical industry has recently attracted significant attention, collagen has aroused significant interest as a biomaterial in medical and tissue engineering applications.&#x0D; OBJECTIVES: In order to create biofilm loaded with biosynthesized ZnNPs for use in chronic wound healing applications, type-I collagen was extracted from the study's subject. by the acid soluble collagen technique, collagen was isolated from the fish skin of the trevally and identified by SDS-PAGE. Aqueous extract from Cassia fistula leaves was also used to greenly manufacture stable ZnNPs, which were then characterized by UV-Vis, FTIR, and XRD measurements.&#x0D; METHODS: Collagen and ZnNPs were then added to polyvinyl alcohol (PVA), creating a thin biofilm that had a high biocompatibility due to the production method's absence of a chemical reducer and crosslinking agent. When tested against the harmful bacteria, both ZnNPs alone and PVA/Collagen/ZnNPs biofilms showed potent antibacterial activity.&#x0D; RESULTS: By using the MTT test, the cytotoxic effects of collagen and ZnNPs on the Vero cell line were evaluated. With 97.76% wound closure, the PVA/Collagen/ZnNPs biofilm demonstrated strong in vitro wound scratch healing efficacy.&#x0D; CONCLUSION: The findings show that the PVA/Collagen/ZnNPs film dramatically increased cell migration by 40.0% at 24 hours, 79.20% at 48 hours, and 97.76% at 74 hours.

Collagen derived from a giant African snail (Achatina achatina) for biomedical applications

Achatina achatina (AA) is a rich source of collagen due to its large size, but it is underutilized. Type I collagen was extracted from AA to serve as an alternative to existing collagen sources. The collagen was extracted at varying alkaline and temperature conditions to determine the optimal parameters that would give a high yield of acid-soluble collagen. The extracted collagen was characterised using X-ray diffraction, Fourier transform infrared (FTIR) spectrometry, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) to confirm the integrity and purity of the extracted collagen. The type of collagen was determined using sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The α-1, α-2, and dimer electrophoresis bands confirmed that the collagen is type I, and the XRD data supported the findings. The highest collagen yield was obtained at 4 ℃ for 48 h, which decreased with increasing temperature due to the instability of the protein in acid at high temperatures. A cytotoxicity test was conducted using an Alamar blue assay. The AA collagen-treated normal prostate cell line (PNT2) showed no significant difference from the untreated control cells. The high-quality type I collagen extracted from AA has the potential for biomedical and other industrial applications.

Extraction and Characterization of Fish Collagen for Enhanced Wound Healing Activity on A549 Cell Lines

Collagen is a proteinaceous material that is present abundantly in animal tissues and gives physical strength and stability to the tissues. Collagen extracted from animal tissues has been applied in the biomedical and healthcare sectors. In recent days, aquatic organisms have shown great potential for collagen extraction and purification. In the present study, we selected three fish species: Naucrates ductor, Oreochromis mossambicus and Cyprinus carpiofor collagen extraction from both their skin and scales. The biomass was pre-treated to remove any non-collagenous matter and fat. Acid-soluble collagen was extracted using acetic acid and a maximum extraction of 51.55±1.02% was reported. The total protein fractions and the denaturation temperatures of the collagen extractswere measured. The molecular weights and the subunit compositions of the collagen extracts were analyzed using SDS-PAGE and the presence of two α chains, one β, and one γ chain. Amino acid profiling was done in an amino acid analyzer after hydrolysis and about one third of the total amino acid content was glycine. The solubility characteristics of the collagenextracts were analyzed at different ranges of pH and salinity. The antimicrobial activities of the collagen extracts were examined against four bacterial species, and it was proven that skin-derived collagens had greater antibacterial potential than extracts of the scales. In vitro studies on the wound healing capacity of the extracted collagen were performed using A549 cell line cultured in F-12K medium, and 95% of cell regeneration was observed in collagen-supplemented dispersed cell lines.

Comprehensive analysis of collagen: unveiling the distinctive characteristics and amino acid profiles from skin and bone of Mesopotamian spiny Eel, Mastacembelus mastacembelus (Banks &amp; Solander, 1794)

Collagen, a pivotal extracellular matrix biomolecule ubiquitous in connective tissues, drew substantial attention due to its widespread presence, notably in skin and bone. This pioneering study delves into the extraction, characterization, and amino acid profiling of acid-soluble collagens (ASC) obtained from the bone (ASC-B) and skin (ASC-S) of the Mesopotamian spiny eel, Mastacembelus mastacembelus (Banks &amp; Solander, 1794). Notably, this research marks the inaugural exploration of this species as a collagen source. Both ASC-S and ASC-B from spiny eel skin and bone exhibited glycine as the predominant amino acid, constituting 29.88 and 29.77 g/100g of collagen for ACS-S and ACS-B, respectively. Fourier transform infrared spectroscopy (FTIR) confirmed the integrated and native nature of both collagens, while X-ray diffraction (XRD) results indicated the preservation of helical structures in both skin and bone collagens. UV-Vis spectra highlighted prominent absorptions at 230 nm. SEM studies revealed the porous and fibrous structure of both ACS-S and ASC-B. Collectively considering UV–Vis and FTIR results alongside the amino acid composition, the extracted collagens were characterized as type I collagen. The collagen isolated from the spiny eel emerges as a potential alternative source of vertebrate collagens with prospective applications in diverse industries, including diet, medical, and pharmaceutical sectors.

Fish By-Product Collagen Extraction Using Different Methods and Their Application.

The processing of fishery resources results in the production of a growing quantity of byproducts, including heads, skins, viscera, intestines, frames, and fillet cutoffs. These byproducts are either wasted or utilized for the production of low-value items and fish oil. Typically, fish processing industries use only 25%, while the remaining 75% is considered as waste by-products. This review presents a comprehensive review on the extraction of collagen from fish byproducts, highlighting numerous techniques including acid-soluble collagen (ASC), enzyme-soluble collagen (ESC), ultrasound extraction, deep eutectic solvent (DES) extraction, and supercritical fluid extraction (SFE). A detailed explanation of various extraction parameters such as time, temperature, solid to liquid (S/L) ratio, and solvent/pepsin concentration is provided, which needs to be considered to optimize the collagen yield. Moreover, this review extends its focus to a detailed investigation of fish collagen applications in the biomedical sector, food sector, and in cosmetics. The comprehensive review explaining the extraction methods, extraction parameters, and the diverse applications of fish collagen provides a basis for the complete understanding of the potential of fish-derived collagen. The review concludes with a discussion of the current research and a perspective on the future development in this research field.

Ultrasonication on Collagen Yield, Physiochemical and Structural Properties from Seabass (Lates Calcarifer) Scales as Affected by Pretreatment and Extraction Conditions

This research explored the use of ultrasound as a pretreatment and extraction assisted process for extraction of collagen from seabass scales. Both acid-soluble (AC) and pepsin-soluble collagens (PC) were extracted with ultrasonication at different extraction times (24 and 48 h). Ultrasound pretreatment (PU) and ultrasound-assisted extraction (UE) notably improved AC extraction yields over 48 hours, registering 2.12% and 4.62%, respectively. The highest yield for PC, 21.85%, was achieved with 48 hours of ultrasound assisted extraction. Protein analysis verified the extracted collagens as type I, indicated by the presence of specific α and β chains. Further, FTIR spectra confirmed collagen's presence in all samples through distinct amide band peaks. Interestingly, ultrasound processes marginally reduced AC's thermal stability while boosting PC's thermal stability, especially when combined with pepsin treatment. Moreover, CD spectroscopy showed the preserved native structure of collagen across all samples. The ultrasound method increased collagen extraction yields and retained its structural integrity. These outcomes are pivotal for advancing collagen extraction methods in the biomedical and food sectors. Keywords: Seabass scales, Collagen, Ultrasonication, Molecular characterization, Physicochemical properties

Dual functional profluorescent nitroxides for the detection of reactive oxygen species and inhibition of collagen degradation during reassembly.

High content of reactive oxygen species (ROS) in the human body leads to oxidative stress and serious health problems, such as cancer and cardiovascular or bone diseases. It is also one of the agents that cause collagen damage. Herein, detection of ROS, scavenging of formed carbon-centered radicals and inhibition of collagen fragmentation were performed in a single operation using newly synthesized profluorescent nitroxide PN1via a switch-on approach. Reassembly of acid soluble collagen (ASC) in the presence of hydroxyl and hydroperoxyl radicals, representatives of ROS, was monitored to study the efficiency of the PN1 probe. Self-assembly curves of collagen fibril solution were in accordance with differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) observations, and indicated that PN1 efficiently inhibited the collagen chain scission. In order to prevent the leakage of the probe in materials, a PN2 monomer was successfully incorporated with MMA to form a profluorescent copolymer probe. Furthermore, PN1 and PN2-MMA copolymer probes offered high sensitivity of detection of ROS in the presence of collagen fibrils with detection limits of 1.1 and 2.7 μM, respectively. The mechanism of ROS detection and inhibition of collagen degradation by profluorescent nitroxides was proposed.