Comparison of the Structural Characteristics of Native Collagen Fibrils Derived from Bovine Tendons using Two Different Methods: Modified Acid-Solubilized and Pepsin-Aided Extraction

Development of a Synergistic Nanomaterial Scaffold Combining Silver Nanoparticles, Collagen, and Doxycycline for Enhanced Scar-Free Skin Regeneration

Introduction The efficacy of wound-healing treatments can be significantly enhanced through innovative combination therapies. This research investigates the wound-healing properties of a combination therapy involving silver nanoparticles (AgNPs) synthesized using Delphinium denudatum (Dd), bovine tendon collagen (BTC), and the antibiotic doxycycline (DOX) in Wistar albino rats. Each component has known therapeutic benefits: AgNPs possess antimicrobial properties, BTC aids in tissue regeneration, and DOX is an effective antibiotic. The synergy between these components is hypothesized to enhance wound closure, reduce inflammation, and promote scar-free healing. Methods The synthesis of DdAgNPs was carried out using Dd. The presence of AgNPs was confirmed by ultraviolet-visible (UV-Vis) spectroscopy and high-resolution transmission electron microscopy (HRTEM). The study was conducted on Wistar albino rats following ethical guidelines for animal research. The rats were divided into different groups to receive various treatments: DdAgNPs alone, BTC alone, DOX alone, combinations of two components, and the triple combination of DdAgNPs: BTC: DOX. Wound closure rates, epithelialization, and collagen deposition were monitored and recorded over time. Tissue samples from the wound sites were collected for histological analysis. Hematoxylin and eosin (H&E) staining was used to evaluate epithelialization and overall tissue architecture. Collagen deposition was assessed using Masson's trichrome staining. Additionally, the expression of cyclooxygenase-2 (COX-2) was measured as an indicator of inflammation. Results UV-Vis spectroscopy provided the characteristic surface plasmon resonance peak indicative of AgNPs, while HRTEM revealed the morphology and size of the nanoparticles, showing spherical particles with an average size of 35±10.42 nm. The combination therapy of DdAgNPs: BTC: DOX significantly enhanced wound closure compared to individual and dual-component treatments. This was evidenced by faster epithelialization and increased collagen deposition. The histological analysis showed that the triple combination treatment resulted in more organized tissue architecture and denser collagen fibers. Furthermore, the treatment led to a marked decrease in COX-2 expression, indicating reduced inflammation and potential for lower scar formation. Conclusion The synergistic application of DdAgNPs, BTC, and DOX presents a promising strategy for advanced wound healing and tissue regeneration. The combination therapy not only accelerates wound closure but also enhances the quality of healing by promoting epithelialization and collagen deposition while reducing inflammation. These findings offer a potential pathway for developing effective, scar-free healing solutions, highlighting the benefits of integrating multiple therapeutic agents in wound care.

Fortified electrospun collagen utilizing biocompatible Poly Glycerol Sebacate prepolymer (PGSp) and zink oxide nanoparticles (ZnO NPs) for diabetics wound healing: Physical, biological and animal studies

Collagen, a naturally occurring fibrous protein, is a potential resource of biological materials for tissue engineering and regenerative medicine because it is structurally biocompatible, has low immunogenicity, is biodegradable, and is biomimetic. Numerous studies have documented in the literature how Collagen nanofibers exhibit limited cell adhesion, poor viscosity, and no interior fibril structure. The biomedical industry is using Poly Glycerol Sebacate prepolymer(PGSp), a biodegradable and biocompatible polyester with high adhesion and very viscous appearance, more often. Here, unique electrospun Collagen/PGSp/ZnO/NPs blend nanofibers for skin tissue application were developed and described with varied PGSp percent. Additionally, when ternary blends of Collagen, PGSp, and Zink Oxide Nanoparticles (ZnO NPs) are used, the antibacterial properties of the scaffolds are improved. The bead-free electrospun nanofibers were produced by raising the PGSp concentration to 30%w/w. SEM, EDS, tensile, MTT, FTIR, SDS-page, swelling test, contact-angle, antimicrobial, biodegradation, XRD, and cell attachment procedures were used to characterize the crosslinked nanofibers. The ternary blend nanofibers with a weight ratio of Collagen/PGSp 30%/ZnONPs 1% had higher stress/strain strength (0.25 mm/mm), porosity (563), cell survival, and degradation time. Moreover, after applying for wound healing in diabetic rats, Collagen/PGSp 30%/could be show improving wound healing significantly compared to other groups.

A green strategy for collagen extraction from tannery raw trimmings using papain enzyme: Process optimization by MW-TOPSIS for enhanced yield

The leather industry poses a significant environmental problem through the extensive discharge of trimming waste, primarily composed of skin matrix rich in proteins. Developing a green approach for utilizing this waste can contribute to the sustainable recovery of proteins, transforming them into valuable bioresources. This study introduces an environmentally friendly and economically viable approach to extract collagen from tannery raw trimming waste using papain enzyme-derived from papaya leaves. The research involved extensive assessments and trials to optimize the enzymatic hydrolysis process. The highest collagen recovery was achieved by hydrolyzing 5 % (w/v) delimed powder with 4 % (w/v) crude papain enzyme from papaya leaf powder, maintaining it at 60 °C for 6 h and at pH 5. Collagen extraction from raw trimming waste using acetic acid was also performed, with the optimized papain enzyme-based hydrolysis process resulting in approximately 91 % yield, while conventional acetic acid method yielded approximately 84 %. To evaluate the performance of the enzymatic hydrolysis process in comparison to acid hydrolysis and hydrothermal hydrolysis, an integrated MW-TOPSIS framework was proposed. This framework determined that enzymatic hydrolysis achieved the highest closeness coefficient value (Ri = 0.40), indicating its superiority as the preferred alternative among the tested methods.

On the effect of pepsin incubation on type I collagen from horse tendon: Fine tuning of its physico-chemical and rheological properties

Type I collagen is commonly recognized as the gold standard biomaterial for the manufacturing of medical devices for health-care related applications. In recent years, with the final aim of developing scaffolds with optimal bioactivity, even more studies focused on the influence of processing parameters on collagen properties, since processing can strongly affect the architecture of collagen at various length scales and, consequently, scaffolds macroscopic performances. The ability to finely tune scaffold properties in order to closely mimic the tissues' hierarchical features, preserving collagen's natural conformation, is actually of great interest. In this work, the effect of the pepsin-based extraction step on the material final properties was investigated. Thus, the physico-chemical properties of fibrillar type I collagens upon being extracted under various conditions were analyzed in depth. Correlations of collagen structure at the supramolecular scale with its microstructural properties were done, confirming the possibility of tuning rheological, viscoelastic and degradation properties of fibrillar type I collagen.

Effects of ultrasound on the structural and functional properties of sheep bone collagen

The study evaluated the effect of an ultrasound-assisted treatment on the structural and functional properties of sheep bone collagen (SBC). The type and distribution of SBC were analyzed by proteome (shotgun) technology combined with liquid chromatography-tandem mass spectrometry. Compared with pepsin extraction, the ultrasound-assisted treatment significantly increased the collagen extraction rate by 17.4 pp (P < 0.05). The characteristic functional groups and structural integrity of collagen extracted by both methods were determined via Fourier transform infrared spectroscopy, ultraviolet absorption spectroscopy, and fluorescence spectroscopy. Circular dichroism spectra revealed that the ultrasound-assisted pretreatment reduced α-helix content by 1.6 pp, β-sheet content by 21.9 pp, and random coils content by 28.4 pp, whereas it increased β-turn content by 51.9 pp (P < 0.05), compared with pepsin extraction. Moreover, ultrasound-assisted treatment collagen had superior functional properties (e.g., solubility, water absorption, and oil absorption capacity) and foaming and emulsion properties, compared with pepsin extraction. Furthermore, the relative content of type I collagen in ultrasound-assisted extracted SBC was highest at 79.66%; only small proportions of type II, VI, X, and XI collagen were present. Peptide activity analysis showed that SBC had potential antioxidant activity, dipeptidyl peptidase 4 inhibitory activity, and angiotensin-converting enzyme inhibitory activity; it also had anticancer, antihypertensive, anti-inflammatory, and immunomodulatory effects.

Ultrasound-assisted extraction of collagen from broiler chicken trachea and its biochemical characterization

Broiler chicken tracheas are a co-product from chicken slaughterhouses which are normally turned into low value animal feed despite their high levels of collagen. Typical collagen extraction by acid and/or pepsin usually results in relatively low yield. Ultrasound-assisted extraction (UAE) could be a means to improve collagen yield. The objectives of this study were to investigate the effects of ultrasonic parameters on the yield and biochemical properties of trachea collagen (TC). Conventional extraction using acetic acid and pepsin for 48 h resulted in acid-soluble (AS) and pepsin-soluble (PS) collagen with a yield of 0.65% and 3.10%, respectively. When an ultrasound with an intensity of 17.46 W·cm-2 was applied for 20 min, followed by acid extraction for 42 h (U-AS), the collagen yield increased to 1.58%. A yield of 6.28% was obtained when the ultrasound treatment was followed by pepsin for 36 h (U-PS). PS and U-PS contained collagen of 82.84% and 85.70%, respectively. Scanning electron microscopy images revealed that the ultrasound did not affect the collagen microstructure. All collagen samples showed an obvious triple helix structure as measured by circular dichroism spectroscopy. Fourier transform infrared spectroscopy indicated that the ultrasound did not disturb the secondary structure of the protein in which approximately 30% of the α-helix content was a major structure for all collagen samples. Micro-differential scanning calorimetry demonstrated that the denaturation temperature of collagen in the presence of deionized water was higher than collagen solubilized in 0.5 M acetic acid, regardless of the extraction method. All collagen comprised of α1 and α2-units with molecular weights of approximately 135 and 116 kDa, respectively, corresponding to the type I characteristic. PS and U-PS collagen possessed higher imino acids than their AS and U-AS counterparts. Based on LC-MS/MS peptide mapping, PS and U-PS collagen showed a high similarity to type I collagen. These results suggest that chicken tracheas are an alternative source of type I collagen. UAE is a promising technique that could increase collagen yield without damaging its structure.

Impact of Ultrasonication on the Self-Assembly Behavior and Gel Properties of Bovine Bone Collagen I

This study deliberated the effect of ultrasonic treatment on collagen self-assembly behavior and collagen fibril gel properties. Bovine bone collagen I which had undergone ultrasonic treatment with different power (0–400 W) and duration (0–60 min) was analyzed. SDS-PAGE and spectroscopic analysis revealed that ultrasonic treatment decreased collagen molecular order degree and the number of hydrogen bonds, stretching collagen telopeptide regions while maintaining the integrity of the collagen triple-helical structure. Ultrasonic treatment (p ≤ 200 W, t ≤ 15 min) dispersed the collagen aggregates more evenly, and accelerated collagen self-assembly rate with a decreased but more homogeneous fibril diameter (82.78 ± 16.47–115.52 ± 19.51 nm) and D-periodicity lengths (62.1 ± 2.9–66.5 ± 1.8 nm) than that of the untreated collagen (119.15 ± 27.89 nm; 66.5 ± 1.8 nm). Meanwhile, ultrasonic treatment (p ≤ 200 W, t ≤ 15 min) decreased the viscoelasticity index and gel strength, enhancing thermal stability and promoting specific surface area and porosity of collagen fibril gels than that of the untreated collagen fibril gel. These results testified that collagen self-assembly behavior and collagen fibril gel properties can be regulated by ultrasonic treatment through multi-hierarchical structural alteration. This study provided a new approach for controlling in vitro collagen fibrillogenesis process so as to manufacture novel desirable collagen-based biomaterials with propitious performances for further valorization.

Potential implications of the glycosylation patterns in collagen α1(I) and α2(I) chains for fibril assembly and growth

O-Glycosylation of hydroxylysine (Hyl) in collagen occurs at an early stage of biosynthesis before the triple-helix has formed. This simple post-translational modification (PTM) of lysine by either a galactosyl or glucosylgalactosyl moiety is highly conserved in collagens and depends on the species, type of tissue and the collagen amino acid sequence. The structural/functional reason why only specific lysines are modified is poorly understood, and has led to increased efforts to map the sites of PTMs on collagen sequences from different species and to ascertain their potential role in vivo. To investigate this, we purified collagen type I (Col1) from the skins of four animals, then used mass spectrometry and proteomic techniques to identify lysines that were oxidised, galactosylated, glucosylgalactosylated, or glycated in its mature sequence. We found 18 out of the 38 lysines in collagen type Iα1, (Col1A1) and 7 of the 30 lysines in collagen type Iα2 (Col1A2) were glycosylated. Six of these modifications had not been reported before, and included a lysine involved in crosslinking collagen molecules. A Fourier transform analysis of the positions of the glycosylated hydroxylysines showed they display a regular axial distribution with the same d-period observed in collagen fibrils. The significance of this finding in terms of the assembly of collagen molecules into fibrils and of potential restrictions on the growth of the collagen fibrils is discussed.

Extraction and Characterization of Pepsin- and Acid-Soluble Collagen from the Swim Bladders of Megalonibea fusca

There is a growing demand for the identification of alternative sources of collagen not derived from land-dwelling animals. The present study explored the use of pepsin- and acid-based extraction protocols to isolate collagen from the swim bladders of Megalonibea fusca. After extraction, these acid-soluble collagen (ASC) and pepsin-soluble collagen (PSC) samples respectively were subjected to spectral analyses and sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) characterization, revealing both to be comprised of type I collagen with a triple-helical structure. The imino acid content of these ASC and PSC samples was 195 and 199 residues per 1000 residues, respectively. Scanning electron microscopy demonstrated that samples of freeze-dried collagen exhibited a compact lamellar structure, while transmission electron microscopy and atomic force microscopy confirmed the ability of these collagens to undergo self-assembly into fibers. ASC samples exhibited a larger fiber diameter than the PSC samples. The solubility of both ASC and PSC was highest under acidic pH conditions. Neither ASC nor PSC caused any cytotoxicity when tested in vitro, which met one of the requirements for the biological evaluation of medical devices. Thus, collagen isolated from the swim bladders of Megalonibea fusca holds great promise as a potential alternative to mammalian collagen.

Modification of Cotton and Leather Surfaces Using Cold Atmospheric Pressure Plasma and TiO2-SiO2-Reduced Graphene Oxide Nanopowders

Surface modification of textile fabrics and leathers is very versatile and allows the products quality improvement. In this work, cotton and leather substrates were pre-treated with cold atmospheric pressure plasma (CAPP) and further coated with TiO₂-SiO₂-reduced graphene oxide composites in dispersion form. By using a Taguchi scheme, this research evaluated the effect of three significant parameters, i.e., the pre-treatment with CAPP, organic dispersion coating and TiO₂-SiO₂-reduced graphene oxide (TS/GR) composites, that may affect the morpho-structural properties and photocatalytic activity of modified cotton and leather surfaces. The characteristics of cotton/leather surfaces were evaluated by morphological, structural, optical and self-cleaning ability using scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX), X-ray powder diffraction (XRD), attenuated total reflection-Fourier Transform Infrared spectroscopy (ATR-FTIR) and UV-Vis spectroscopy. The self-cleaning performance of the obtained cotton and leather samples was evaluated by photocatalytic discoloration of berry juice surface stains under UV light irradiation for 12 h. The successfulness of coating formulations was proven by the SEM analysis and UV-Vis spectroscopy. The XRD patterns and ATR-FTIR spectra revealed the cellulose and collagen structures as dominant components of cotton and leather substrates. The CAPP treatment did not damage the cotton and leather structures. The photocatalytic results highlighted the potential of TiO₂-SiO₂-reduced graphene oxide composites in organic dispersion media, as coating formulations, for further use in the fabrication of innovative self-cleaning photocatalytic cotton and leather products.

Preparation of immobilized pepsin for extraction of collagen from bovine hide

In the extraction of collagens from mammalian tissues, the free pepsin used in the acid-pepsin extraction system is hard to recycle, and there is a risk of enzyme protein contamination in the extracted collagen products, which limits their applications. To solve this problem, an immobilized pepsin was successfully prepared via the covalent crosslinking of glutaraldehyde using a 3-aminopropyltriethoxysilane (APTES) surface modified silica clay as the support. The immobilized pepsin was applied for the extraction of collagen from bovine hide. The optimal immobilization process involves incubating pepsin with an initial concentration of 35 mg mL^-1 and glutaraldehyde with 5% activated APTES modified silica clay at 25 °C for 60 min, by which the loading amount of pepsin was 220 mg g^-1 and the activity of the immobilized pepsin was 4.2 U mg^-1. The collagen extracted using acetic acid and the immobilized pepsin method retained its complete triple helix structure. This research thus details an effective separation method using pepsin for extraction of collagen via an acetic acid-enzyme method, where the extracted collagen may be a candidate for use in biomaterial applications.

Role of 3-Methacryloxypropyltrimethoxysilane in Dentin Bonding

In this study, we aimed to examine the effect of 3-methacryloxypropyltrimethoxysilane (MPS) on dentin collagen and the impact of MPS and 10-methacryloyloxydecyl dihydrogen phosphate (MDP) together and separately on resin-dentin bonding. Eight groups of primers were prepared: control group, MDP, MPS5, MPS5 + MDP, MPS10, MPS10 + MDP, MPS15, and MPS15 + MDP. The potential interaction between MPS and collagen was assessed by molecular dynamics, contact angle measurement, zeta potential measurement, and chemoanalytic characterization using X-ray photoelectron spectroscopy, Raman spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, and ultraviolet-visible spectroscopy. Microtensile bond strength (μTBS) and nanoleakage were evaluated after 24 h or 12 months of water storage. In situ zymography was used to evaluate the enzyme activity at the bonded interface. According to chemoanalytic characterization and molecular dynamics, a weak interaction between MPS and collagen was observed. MPS enhanced the hydrophobicity and negative charge of the collagen surface (P < 0.05). Applying an MDP-containing primer increased μTBS (P > 0.05) and reduced fluorescence after 24 h of water storage. Water storage for 12 months decreased μTBS (P < 0.05) and increased nanoleakage for all groups. MPS conditioning did not change μTBS and nanoleakage after 24 h of water storage or aging. The MPS10 + MDP and MPS15 + MDP groups presented more silver nitrate and μTBS decrease than the MDP group (P < 0.05). These results indicated that MPS had a weak interaction with collagen that enhanced its surface negative charge and hydrophobicity without adversely affecting dentin bonding. However, compared to MDP alone, mixing MDP with MPS impaired their effectiveness and made the dentin bonding unstable.

Developments for Collagen Hydrolysate in Biological, Biochemical, and Biomedical Domains: A Comprehensive Review

The collagen hydrolysate, a proteinic biopeptide, is used for various key functionalities in humans and animals. Numerous reviews explained either individually or a few of following aspects: types, processes, properties, and applications. In the recent developments, various biological, biochemical, and biomedical functionalities are achieved in five aspects: process, type, species, disease, receptors. The receptors are rarely addressed in the past which are an essential stimulus to activate various biomedical and biological activities in the metabolic system of humans and animals. Furthermore, a systematic segregation of the recent developments regarding the five main aspects is not yet reported. This review presents various biological, biochemical, and biomedical functionalities achieved for each of the beforementioned five aspects using a systematic approach. The review proposes a novel three-level hierarchy that aims to associate a specific functionality to a particular aspect and its subcategory. The hierarchy also highlights various key research novelties in a categorical manner that will contribute to future research.

Physicochemical characterization and self-assembly of human amniotic membrane and umbilical cord collagen: A comparative study

The diverse application of collagen has created a need to discover renewable and economical sources with prevailing/improved physico-chemical properties. To address this scenario, the present study has extracted collagen from Human Amniotic Membrane (AM) and Umbilical cord, which are treated as medical waste and compared its physico-chemical properties. Collagen was extracted by pepsin solubilization using various salt concentrations (1 M, 2 M and 4 M). Umbilical Cord Collagen (UC) yield was 10% higher than Amniotic Membrane Collagen (AC). UC reported 58% higher sulphated glycosaminoglycan content than AC. Electrophoretic pattern of AC and UC in both disulphide bond reducing and non-reducing conditions showed bands corresponding to collagen type I, III, IV, V and XV. Collagen morphology was examined using SEM and the amino acid content was quantified by HPLC and LC-MS/MS. Triple helicity was confirmed by CD and FTIR spectra. Thermal transition temperature of AC and UC was found equivalent to animal collagen. Self-assembly, fibril morphology and spatial alignment was studied using AFM and DLS. Biocompatibility was analyzed using 3T3 fibroblast cells. In conclusion, UC with higher yield, presented with better physico-chemical, structural and biological properties than AC could serve as an efficient alternative to the existing animal collagen for diverse applications.

Pepsin and Laryngeal and Hypopharyngeal Carcinomas

Laryngeal and hypopharyngeal carcinomas are common malignant tumors of the head and neck, and the incidence of both is increasing. Laryngopharyngeal reflux refers to the retrograde flow of gastric contents into the larynx, oropharynx, and/or nasopharynx. It remains controversial whether laryngopharyngeal reflux is a risk factor for laryngeal and hypopharyngeal cancers. The refluxing substances mainly include hydrochloric acid, pepsin, and occasionally bile acids and bile salts, as well as bacteria that colonize the gastrointestinal tract. Loss of epithelium in the mucous membrane of the larynx and hypopharynx is thought to be caused by pepsin. Here, we review the relationships between laryngopharyngeal reflux and both laryngeal and hypopharyngeal carcinomas, as well as the significance of pepsin, methods of clinical detection, and the mechanism of carcinogenesis.