Nile tilapia skin collagen sponge modified with chemical cross-linkers as a biomedical hemostatic material

Novel collagen gradient membranes with multiphasic structures: Preparation, characterization, and biocompatibility

Scaffolds with multiphasic structures are considered to be superior for guided tissue regeneration. Two types of tilapia skin collagen gradient membranes (stepped gradient and linear gradient) with multiphasic structures were prepared by controlling the collagen concentrations and the freezing rates. The results revealed that collagen gradient membranes were more capable of guiding tissue regeneration compared to homogeneous membranes. These two gradient membranes featured a dense outer layer and a loose inner layer, with good mechanical properties as indicated by tensile strengths of more than 250 Kpa and porosities exceeding 85 %. Additionally, these membranes also showed good hydrophilicity and water absorption, with an inner layer contact angle of less than 91° and a water absorption ratio greater than 40 times. Furthermore, the multiphasic scaffolds were proved to be biocompatible by the acute toxicity assay, the intradermal irritation test and so on. Gradient membranes could effectively promote the adhesion and proliferation of fibroblasts and osteoblasts, through elevating the TGF-β/Smad signaling pathway by TGF-β and Smads, and activating the Wnt/β-catenin signaling pathway by LRP5 and β-catenin, similar to homogenous membranes. Therefore, collagen gradient membranes from tilapia skin show important application value in guiding tissue regeneration.

Collagen/Curdlan composite sponge for rapid hemostasis and skin wound healing

Collagen's unique properties promise hemostatic potential, but its sponge form's stability and mechanics need improvement. In this study, we developed a series of homeostatic sponges by co-assembling collagen and curdlan at different ratios into hydrogels, followed by freeze-drying treatment. The incorporation of curdlan into collagen sponges has been found to significantly enhance the sponge's properties, including increased porosity, elevated water uptake, improved elasticity, and enhanced resistance to degradation. In vitro cytotoxicity and hemolysis assays have demonstrated the biocompatibility and nontoxicity of composite sponges. In mouse liver perforation and incision models, the composite sponges achieved rapid coagulation within 67 s and 75 s, respectively, outperforming gauze and gelatin sponge in reducing blood loss. Furthermore, composite sponges demonstrated superior wound healing potential in mice full-thickness skin defects model, with accelerated healing rates observed at days 3, 7, and 14 compared to the control group. Overall, collagen/curdlan composite sponge show promise for hemostasis and wound healing applications.

A highly biocompatible CE-crosslinked collagen implant with exceptional anti-calcification and collagen regeneration capabilities for aging skin rejuvenation

Skin aging, a complex and inevitable biological process, results in wrinkles, dermal laxity, and skin cancer, profoundly influencing appearance and overall health. Collagen serves as the fundamental element of the dermal matrix; nevertheless, collagen is susceptible to enzymatic degradation within the body. Crosslinking is employed to enhance the physicochemical properties of collagen. However, conventional crosslinking agents may harbor potential issues such as cytotoxicity and calcification risks, constraining their application in the biomedical field. Therefore, we have for the first time developed a highly biocompatible CE-crosslinked collagen implant with exceptional anti-calcification and collagen regeneration capabilities for aging skin rejuvenation. A novel collagen crosslinking agent (CE) was synthesized through a reaction involving chitosan quaternary ammonium salt with 1,4-butanediol diglycidyl ether. Compared to collagen crosslinked with glutaraldehyde (GA), the CE-crosslinked collagen implant exhibited notable stability and durability. The implant demonstrated excellent injectability and viscosity, resisting displacement after implantation. Additionally, the CE-crosslinked collagen implant displayed superior biocompatibility, effectively promoting the proliferation and adhesion of HFF-1 cells compared with the GA-crosslinked collagen. The CE-crosslinked collagen represented a safer and more biologically active implant material. In vivo experiments further substantiated that the implant significantly facilitated collagen regeneration without inducing calcification. The innovative collagen implant has made substantial strides in enhancing aesthetics and reducing wrinkles, presenting the potential for revolutionary progress in the fields of skin rejuvenation and collagen regeneration.

Carbonized Cellulose Aerogel Derived from Waste Pomelo Peel for Rapid Hemostasis of Trauma-Induced Bleeding

Uncontrollable massive bleeding caused by trauma will cause the patient to lose a large amount of blood and drop body temperature quickly, resulting in hemorrhagic shock. This study aims to develop a hemostatic product for hemorrhage management. In this study, waste pomelo peel as raw material is chosen. It underwent processes of carbonization, purification, and freeze-drying. The obtained carbonized pomelo peel (CPP) is hydrophilic and exhibits a porous structure (nearly 80% porosity). The water/blood absorption ratio is significantly faster than the commercial Gelfoam and has a similar water/blood absorption capacity. In addition, the CPP showed a water-triggered shape-recoverable ability. Moreover, the CPP shows ideal cytocompatibility and blood compatibility in vitro and favorable tissue compatibility after long terms of subcutaneous implantation. Furthermore, CPP can absorb red blood cells and fibrin. It also can absorb platelets and activate platelets, and it is capable of achieving rapid hemostasis on the rat tail amputation and hepatectomized hemorrhage model. In addition, the CPP not only can quickly stop bleeding in the rat liver-perforation and rabbit heart uncontrolled hemorrhage models, but also promotes rat liver and rabbit heart tissue regeneration in situ. These results suggest the CPP has shown great potential for managing uncontrolled hemorrhage.

A highly bioactive THPC-crosslinked recombinant collagen hydrogel implant for aging skin rejuvenation

Skin aging, a complex physiological progression marked by collagen degradation, poses substantial challenges in dermatology. Recombinant collagen emerges as a potential option for skin revitalization, yet its application is constrained by difficulties in forming hydrogels. We have for the first time developed a highly bioactive Tetrakis(hydroxymethyl) phosphonium chloride (THPC)-crosslinked recombinant collagen hydrogel implant for aging skin rejuvenation. THPC demonstrated superior crosslinking efficiency compared to traditional agents such as EDC/NHS and BDDE, achieving complete recombinant collagen crosslinking at minimal concentrations and effectively inducing hydrogel formation. THPC's four reactive hydroxymethyl groups facilitate robust crosslinking with triple helical recombinant collagen, producing hydrogels with enhanced mechanical strength, excellent injectability, increased stability, and greater durability. Moreover, the hydrogel exhibited remarkable biocompatibility and bioactivity, significantly promoting the proliferation, adhesion, and migration of human foreskin fibroblast-1. In photoaged mice skin models, the THPC-crosslinked collagen hydrogel implant notably improved dermal density, skin elasticity, and reduced transepidermal water loss, creating a conducive environment for fibroblast activity and healthy collagen regeneration. Additionally, it elevated superoxide dismutase (SOD) activity and displayed substantial anti-calcification properties. The THPC-crosslinked recombinant collagen hydrogel implant presents an innovative methodology in combating skin aging, offering significant promise in dermatology and tissue engineering.

Preparation and Modification of Collagen/Sodium Alginate-Based Biomedical Materials and Their Characteristics

(1) Background: Collagen and sodium alginate are commonly used in the field of biomedical materials due to their excellent biocompatibility. This study focuses on the preparation, modification, and characterization of collagen/sodium alginate (C/SA)-based biomedical materials. (2) Methods: The characteristics, including surface chemistry, mechanical properties, hygroscopicity, and porosity, were analyzed. The hemostatic activity in vitro was measured using a blood clotting assay and dynamic blood clotting assay. (3) Results: The results from microstructure and porosity measurement revealed that all of the sponges exhibited a porosity of more than 95 percent. The sponge cross-linked with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide (EDC/NHS) showed better tensile strength and lower elongation at break. The sponges cross-linked with EDC/NHS and oxidized sodium alginate (OSA) exhibited the highest hygroscopicity in comparison with the uncross-linked sponge. (4) Conclusions: Our study demonstrated that the C/SA-based material we prepared exhibited a high level of porosity, enabling efficient absorption of tissue exudate and blood. Additionally, the materials revealed excellent hemocompatibility, making them suitable for use as a hemostatic dressing in the field of biomedical materials.

Physicochemical properties and cell proliferation and adhesive bioactivity of collagen-hyaluronate composite gradient membrane

Membrane materials were widely used in guided tissue regeneration (GTR) to prevent fibroblast invasion and form a confined area for preferentially growing of osteoblast. A novel collagen-hyaluronate composite gradient membrane was prepared by Tilapia (Oreochromis mossambicus) skin collagen and sodium hyaluronate for potential GTR applications and their bioactivities were investigated by cellular viability. SEM results indicated the membrane showed a dense outer and a porous inner surface for effectively guiding the growth of bone tissue. Physicochemical and biosafety experiments showed the tensile strength of membrane was 466.57 ± 44.31 KPa and contact angle was 74.11°, and the membrane showed perfect biocompatibility and cytocompatibility as well, which met the requirements of GTR material. Cell morphology revealed that the membrane could facilitate the adherence and proliferation of fibroblast and osteoblast. The results of qRT-PCR and ELISA demonstrated that the membrane could effectively activate TGF-β/Smad pathway in fibroblast, and promote the expressions of TGF-β1, FN1 and VEGF. Remarkably, RUNX2 was stimulated in BMP2 pathway by the membrane to regulate osteoblast differentiation. In summary, the collagen-hyaluronate composite gradient membrane not only fulfills the prerequisites for use as a GTR material but also demonstrates substantial potential for practical applications in the field.

A nanofiber/sponge double-layered composite membrane capable of inhibiting infection and promoting blood coagulation during wound healing

Uncontrolled bleeding and bacterial infections cause severe damage to the wounds and remain a clinical challenge. Here, we developed a nanofiber/sponge bilayered composite membrane (QCP) containing quaternized silicone (QP12) and quaternized chitosan (QCS12) by joint approaches of electrospinning and freeze-drying and investigated their potential for wound dressing. The QCP was composed of a sponge (QCC) containing collagen (COL) and QCS12 and a nanofibrous membrane (MQP) containing poly-ε-caprolactone (PCL) and QP12. The QCP composite membrane possessed feasible permeability (0.22 ± 0.01 g/(cm²·24 h)), available thermal stability, suitable mechanical properties with natural skin, and in vivo hemostatic efficiency. The bonds of the N-quaternary and Schiff base endow composite membranes with significant anti-microbial invasion, potentially enhancing the wound healing process with an eligible microenvironment. Meanwhile, QCP evinced fine hemocompatibility, low cytotoxicity, negligible skin irritation, and other desirable biosafety as an excellent wound dressing. QCP promoted collagen deposition and re-epithelization to accelerate healing and suppress scars in the full-thickness acute wound models. Furthermore, the evaluation in the chronic skin incision model of diabetes mellitus manifested high healing efficiency with a certain resistance to bacterial infection of the composite membrane. Taken together, the QCP composite membrane may be a potential antibacterial and hemostatic wound dressing.

Preparation of Nile tilapia skin collagen powder by low-temperature and comprehensive evaluation of hemostasis and wound healing

Nile tilapia (hereinafter referred to as tilapia) is a species with high economic value and extensive cultivation. In this study, the low-temperature Nile tilapia skin collagen powder (TSCP) was prepared by liquid nitrogen freeze pulverization. After physical and chemical analysis of its properties, it was found that its characteristics were similar to those of type I collagen. The three-dimensional helix structure of protein peptide is good and non denatured. It shows that cryogenic temperature guarantees the activity of TSCP. In addition, TSCP has good biocompatibility. Specifically, it has good blood compatibility, lacks cytotoxicity, will not cause intradermal stimulation and acute systemic toxicity, and has no obvious rejection after implantation. In the rat liver hemorrhage model and wound repair model, compared with the commercially available bovine collagen powder (BSCP), TSCP has better blood coagulation ability: the shortest hemostatic time (135 s) and wound healing efficiency: the wound healing is obvious on the 14th day. The results of this study indicate that the TSCP is an ideal candidate for hemostatic agents and wound healing dressings.

Evaluating the Degradation Process of Collagen Sponge and Acellular Matrix Implants In Vivo Using the Standardized HPLC-MS/MS Method

The purpose of this study was to establish a collagen determination method based on an isotope-labeled collagen peptide as an internal reference via high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS), and using the established method to evaluate the degradation process of collagen-based implants in vivo. The specific peptide (GPAGPQGPR) of bovine type I collagen was identified with an Orbitrap mass spectrometer. Then, the quantification method based on the peptide detection with HPLC-MS/MS was established and validated, and then further used to analyze the degradation trend of the collagen sponge and acellular matrix (ACM) in vivo at 2, 4, 6, 8, 12, 16, and 18 weeks after implantation. The results indicate that the relative standard deviation (RSD) of the detection precision and repeatability of the peptide-based HPLC-MS/MS quantification method were 3.55% and 0.63%, respectively. The limitations of quantification and detection were 2.05 × 10−3 μg/mL and 1.12 × 10−3 μg/mL, respectively. The collagen sponge and ACM were completely degraded at 10 weeks and 18 weeks, respectively. Conclusion: A specific peptide (GPAGPQGPR) of bovine type I collagen was identified with an Orbitrap mass spectrometer, and a standardized HPLC-MS/MS-based internal reference method for the quantification of bovine type I collagen was established. The method can be used for the analysis of the degradation of collagen-based implants in vivo.

A comparative study on cross-linking of fibrillar gel prepared by tilapia collagen and hyaluronic acid with EDC/NHS and genipin

Chemical cross-linking is an important step to grant satisfying properties to collagen-based materials. However, there are few comparative studies on crossing-linking of collagen-based fibrillar gels which are preferred biomaterials for similar properties to native tissues with different cross-linking agents. In this study, a fibrillar gel was fabricated with tilapia collagen and hyaluronic acid, and cross-linking conditions with EDC/NHS and genipin were discussed. Genipin gave gels much higher equilibrium cross-linking degree than EDC/NHS. ATR-FTIR and XPS showed EDC/NHS offered short-range cross-linking formed by amino and carboxyl groups in fibrils, while genipin induced long-range cross-linking by nucleophilic reaction through attack of amino groups in fibrils on carbon atoms at C-3 as well as ester groups in genipin, besides improved hydrogen bonds. XRD and SEM revealed the structural integrity of gels was strengthened after cross-linking, whereas fibril bundles disaggregated into thin fibrils. Consequently, swelling capacity and anti-degraded property were enhanced significantly, while thermal stability weakened. The fibrillar gels had good biocompatibility, but interestingly the appearance and migration of L929 fibroblasts were influenced by cross-linking degree. These results demonstrated that aquatic collagen-based fibrillar gel cross-linked by genipin had greater potential in biomaterials than EDC/NHS, whereas the cross-linking degree should be controlled.

Preparation of norfloxacin-grafted chitosan antimicrobial sponge and its application in wound repair

Trauma is one of the most common health issues in humans, and bacterial infection of the wound may result in many complications. In this paper, using 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) as a coupling agent, chitosan (CS) was grafted with norfloxacin (NF), an antibacterial agent, to prepare a CS-NF sponge by freezing-induced phase separation. The CS-NF sponge was characterized by ultra violet-visible spectroscopy, Fourier transform infrared spectroscopy, and scanning electron microscopy. Its porosity and water absorption ratio were determined, the antimicrobial activity was evaluated by inhibition zone assay, and its wound repair effect was investigated in a full-thickness cutaneous excisional wound animal model. The results showed that NF was successfully grafted onto CS, and the obtained CS-NF sponge had both a high porosity and water absorption ratio. The CS-NF sponge displayed significant antimicrobial activities in the inhibition zone assay. In vivo the CS-NF sponge exhibited a strong wound healing effect, with a wound healing rate close to 100% by day 15. Therefore, the CS-NF sponge is a novel promising wound-healing dressing for clinical practice.

Biocompatible Films of Collagen-Procyanidin for Wound Healing Applications

The study investigated the effect of polyphenols present in Cassia auriculata (CA) leaves in enhancing the stability of the collagen protein and the wound healing potential of collagen films. The crude ethanol extract of CA was analyzed for the presence of phytochemicals and purified by column chromatography using solvents with increasing polarity. The ethanol eluted active fractions (EEAF) that precipitated gelatin was characterized using HP-TLC, FTIR spectroscopy, ESI-FT-MS/MS, and ¹H NMR spectroscopy. The active compound was identified to be procyanidin B belonging to the proanthocyanidins group. The wound healing property of EEAF and collagen type I extracted from Clarias batrachus fish skin and the bovine tendon was assessed by in vitro scratch assay on L929 mice fibroblast cell lines. The EEAF-treated collagen coating enhanced in vitro wound closure in comparison with the uncoated dish. It was observed that EEAF treatment improved the physical strength of collagen films. The in vivo wound healing of the EEAF-treated collagen film was examined in male Wister rats and the wound site tissues were assessed. In vivo wound examination showed enhanced healing with EEAF incorporated collagen films. Comparatively, the EEAF-treated bovine tendon collagen films showed improved physical properties and better wound healing property than fish collagen films.

Analysis of the Physico-Chemical, Mechanical and Biological Properties of Crosslinked Type-I Collagen from Horse Tendon: Towards the Development of Ideal Scaffolding Material for Urethral Regeneration

Urethral stenosis is a pathological condition that consists in the narrowing of the urethral lumen because of the formation of scar tissue. Unfortunately, none of the current surgical approaches represent an optimal solution because of the high stricture recurrence rate. In this context, we preliminarily explored the potential of an insoluble type-I collagen from horse tendon as scaffolding material for the development of innovative devices for the regeneration of injured urethral tracts. Non-porous collagen-based substrates were produced and optimized, in terms of crosslinking density of the macromolecular structure, to either provide mechanical properties compliant with the urinary tract physiological stress and better sustain tissue regeneration. The effect of the adopted crosslinking strategy on the protein integrity and on the substrate physical-chemical, mechanical and biological properties was investigated in comparison with a decellularized matrix from porcine small intestinal submucosa (SIS patch), an extensively used xenograft licensed for clinical use in urology. The optimized production protocols allowed the preservation of the type I collagen native structure and the realization of a substrate with appealing end-use properties. The biological response, preliminarily investigated by immunofluorescence experiments on human adult renal stem/progenitor cells until 28 days, showed the formation of a stem-cell monolayer within 14 days and the onset of spheroids within 28 days. These results suggested the great potential of the collagen-based material for the development of scaffolds for urethral plate regeneration and for in vitro cellular studies.

Typical structure, biocompatibility, and cell proliferation bioactivity of collagen from Tilapia and Pacific cod

Aquatic collagens, as the alternative sources of mammalian collagen, have received increasing attention due to its low-cost, low-antigenicity, biocompatibility, and biodegradability. Pepsin-soluble collagens were extracted from the skins of Oreochromis mossambicus (Om-PSC) and Gadus macrocephalus (Gm-PSC), and their structural properties and bioactivities were probed to reveal their potential applications in biomedical material for tissue engineering. The results of Fourier transforms-infrared spectroscopy (FT-IR), circular dichroism (CD), X-ray diffraction (XRD), ultraviolet (UV) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) demonstrated that Om-PSC and Gm-PSC had similar and intact triple helical structures. The amino acid composition and peptide profiles revealed Om-PSC and Gm-PSC were identified as type I collagen with the typical repetitive sequence of (Gly-X-Y) _n. However, the denaturation temperature (T_d) was determined to be 29.7 ℃ of Om-PSC, much higher than that of Gm-PSC (17.3 ℃). Toxicological experiments demonstrated Om-PSC and Gm-PSC both had good biocompatibility and cytocompatibility, which met the requirements of medical materials. Fluorescence imaging and cell cycle distribution revealed Om-PSC and Gm-PSC could promote the proliferation of fibroblast and osteoblast cells. Therefore, Om-PSC and Gm-PSC showed the advantages in medical materials.

A collagen-based bi-layered composite dressing for accelerated wound healing

AIM OF THE STUDY

The aim of the study was to fabricate collagen-based composite dressings, evaluate the efficiency for wound healing and reveal the mechanism of promoting wound healing.

MATERIALS AND METHODS

An innovative bi-layered composite wound dressing was developed using two marine biomacromolecules (collagen and chitosan). Full-thickness skin defect model was performed to evaluate the wound healing activity in vivo. The levels of inflammatory cytokines including tumor necrosis factor alpha (TNF-α), interleukin (IL-1, IL-6, IL-8) and growth factors like transforming growth factor beta (TGF-β), vascular epidermal growth factor (VEGF) and basic fibroblast growth factor (bFGF) were quantified by ELISA assays. The total amount of collagen was quantified by hydroxyproline content. The proliferation and viability of fibroblast cells cultured on collagen sponges were determined by CCK-8 assay.

RESULTS

The results of wound closure and histopathological analysis indicated that non-crosslinked collagen-based bi-layered composite dressing stimulated wound healing, accelerated re-epithelialization and accomplished wound healing within a time span of 28 days. The results of levels of inflammatory cytokines and growth factors showed that collagen-based composite dressings could reduce the inflammatory response and upregulate growth factors levels to accelerate the wound healing. The results of hydroxyproline content and CCK-8 assay indicated that collagen-based composite dressings could also promote collagen synthesis and fibroblasts viability and proliferation.

CONCLUSION

The non-crosslinked collagen-based bi-layered composite dressing could be applied for an efficient and ideal wound dressing. Therefore, the findings provided the essential theoretical basis for the potential of collagen-based composite dressing applied in wound healing fields.

Facile extrusion 3D printing of gelatine methacrylate/Laponite nanocomposite hydrogel with high concentration nanoclay for bone tissue regeneration

The extrusion 3D printing of hydrogels has evolved as a promising approach that can be applied for specific tissue repair. However, the printing process of hydrogel scaffolds with high shape fidelity is inseparable from the complex crosslinking strategy, which significantly increases the difficulty and complexity of printing. The aim of this study was to develop a printable hydrogel that can extrude at room temperature and print scaffolds with high shape fidelity without any auxiliary crosslinking during the printing process. To this end, a novel formulation consisting of a Laponite suspension with a high solid concentration and a gelatine methacrylate (GelMA) nanocomposite hydrogel was developed. A homogeneously dispersed high-concentration (up to 20% w/v) Laponite suspension was obtained by stirring at 0 °C. The addition of Laponite with high concentration improved the rheological properties, the degradation stability, and the mechanical strength of the hydrogel. The formulation of 15% (w/v) GelMA and 8% (w/v) Laponite nanocomposite hydrogel exhibited desirable printability and biocompatibility. The GelMA/Laponite hydrogels significantly promoted bone marrow mesenchymal stem cell (BMSC) proliferation and osteogenic differentiation. Both desirable printability under mild conditions and cyto-compatibility enable composite hydrogel a potential candidate as biomaterial inks to be applied for bone tissue regeneration.

Preparation and evaluation of an innovative antibacterial bi-layered composite dressing for skin wound healing

AIM OF THE STUDY

The aim of the current study was to develop collagen-based bi-layered composite dressings with antibacterial property and evaluate the efficiency for wound healing.

MATERIALS AND METHODS

A bi-layered composite wound dressing was fabricated using two marine biomacromolecules (collagen and chitosan or carboxymethyl chitosan). Non-crosslinked and N-Ethyl-N'-(3-dimethylaminopropyl) carbodiimide/N-Hydroxy succinimide (EDC/NHS) cross-linked collagen sponges fabricated by vacuum freeze-drying technology was used as the inner layer. The medical spun-laced nonwoven coated with chitosan and carboxymethyl chitosan was used as the outer layer. The antibacterial activities against E. coli and S. aureus were evaluated by the inhibition zone assay. Deep second-degree scald model was performed to evaluate the efficiency of bi-layered composite dressings for wound healing.

RESULTS

In view of comprehensive evaluation of appearance and in vitro antibacterial activity, medical spun-laced nonwoven coated with 3% of chitosan solution was chosen to be used as the optimized preparation conditions to produce the outer layer of composite dressing, which acted as a barrier against microorganisms and provided mechanical support. Furthermore, the results of wound closure and histopathological analysis indicated that EDC/NHS cross-linked collagen-based bi-layered composite dressing was superior to non-crosslinked and commercial products, which stimulated the wound healing process and accomplished deep second-degree scalded skin healing within a time span of 28 days.

CONCLUSION

The EDC/NHS cross-linked collagen-based bi-layered composite dressing had immense potential to be applied for an ideal wound dressing for more efficient and faster wound healing. Therefore, the findings provided the essential theoretical basis for great potential of collagen-based composite dressing used in wound healing applications.

Rapid Hemostatic Biomaterial from a Natural Bath Sponge Skeleton

Uncontrolled bleeding is the main cause of mortality from trauma. Collagen has been developed as an important hemostatic material due to its platelet affinity function. A bath sponge skeleton is rich in collagen, also known as spongin. To understand the hemostatic effect of spongin, spongin materials, SX, SFM and SR were prepared from the bath sponge Spongia officinalis, and hemostatic experiments were performed. The SX, SFM and SR were significantly better than the positive control, type I collagen, in shortening the whole blood clotting time in vitro and hemostasis upon rat tail amputation. In a hemostatic experiment of rabbit common carotid artery injury, the hemostatic time and 3 h survival rate of the SFM group were 3.00 ± 1.53 min and 100%, respectively, which are significantly better than those of the commercial hemostat CELOX-A (10.33 ± 1.37 min and 67%, respectively). Additionally, the SFM showed good coagulation effects in platelet-deficient blood and defibrinated blood, while also showing good biocompatibility. Through a variety of tests, we speculated that the hemostatic activity of the SFM is mainly caused by its hyperabsorbency, high affinity to platelets and high effective concentration. Overall, the SFM and spongin derivates could be potential hemostatic agents for uncontrolled bleeding and hemorrhagic diseases caused by deficiency or dysfunction of coagulation factors.

A novel gene recombinant collagen hemostatic sponge with excellent biocompatibility and hemostatic effect

Effect and biosafety are the most noteworthy aspect of the hemostatic materials for trauma treatment. In this work, we evaluated the biocompatibility and hemostatic effect of a novel recombinant collagen hemostatic sponge according to ISO 10993. In addition, the interaction between the recombinant collagen hemostatic sponge and blood cells was observed by scanning electron microscopy, moreover, the hemostatic effect was evaluated by blood clotting assay in vitro and liver hemorrhage models in vivo. As the results, the novel recombinant collagen hemostatic sponge enables to be biodegradable completely in vivo, without stimulation, sensitization, acute toxicity, hematolysis or obvious immune rejection. The procoagulant effect of recombinant hemostatic sponge in vitro is significantly more excellent than that of natural collagen sponge due to the more promotive capacity of blood cell adhesion. Meanwhile, the liver hemorrhage models showed that the hemostatic time of recombinant collagen sponge was 19.33 ± 4.64 s, which was significantly better than that of natural collagen sponge (hemostatic time 31.62 ± 5.63 s). Therefore, the novel recombinant collagen hemostatic sponge with satisfactory biocompatibility and significant hemostatic effect can be performed as a potential novel type of clinical hemostatic products for research and development.

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.

Influences of Molecular Weights on Physicochemical and Biological Properties of Collagen-Alginate Scaffolds

For tissue engineering applications, biodegradable scaffolds containing high molecular weights (MW) of collagen and sodium alginate have been developed and characterized. However, the properties of low MW collagen-based scaffolds have not been studied in previous research. This work examined the distinctive properties of low MW collagen-based scaffolds with alginate unmodified and modified by subcritical water. Besides, we developed a facile method to cross-link water-soluble scaffolds using glutaraldehyde in an aqueous ethanol solution. The prepared cross-linked scaffolds showed good structural properties with high porosity (~93%) and high cross-linking degree (50–60%). Compared with collagen (6000 Da)-based scaffolds, collagen (25,000 Da)-based scaffolds exhibited higher stability against collagenase degradation and lower weight loss in phosphate buffer pH 7.4. Collagen (25,000 Da)-based scaffolds with modified alginate tended to improve antioxidant capacity compared with scaffolds containing unmodified alginate. Interestingly, in vitro coagulant activity assay demonstrated that collagen (25,000 Da)-based scaffolds with modified alginate (C25-A63 and C25-A21) significantly reduced the clotting time of human plasma compared with scaffolds consisting of unmodified alginate. Although some further investigations need to be done, collagen (25,000 Da)-based scaffolds with modified alginate should be considered as a potential candidate for tissue engineering applications.

Fabricating poly(vinyl alcohol)/gelatin composite sponges with high absorbency and water-triggered expansion for noncompressible hemorrhage and wound healing

Composite sponges obtained from PVA and gelatin were synthesized by thiol–ene chemistry and used for controlling noncompressible hemorrhage.

Biocompatibility, hemostatic properties, and wound healing evaluation of tilapia skin collagen sponges

Dialyzed tilapia skin collagen sponge (DTSCS) and self-assembled tilapia skin collagen sponge (STSCS) were prepared by freeze-drying. The raw components used in the fabrication of DTSCS and STSCS were separated and purified from tilapia fish skin. It is anticipated that these collagen sponges could be developed into medical dressings for hemostasis and wound healing. The aim of the present research was to explore the possibility of DTSCS and STSCS as medical dressings and compare their differences by scanning electron microscopy (SEM), water absorption measurement, differential scanning calorimetry (DSC), measurement of porosity, cytotoxicity, hemolysis, in vivo biocompatibility, and evaluation of hemostatic performance and wound healing. The results indicate that DTSCS and STSCS are suitable materials for use in medical applications with a loose and porous structure, high water absorption, high porosity, and high thermal stability. The materials also displayed good biocompatibility, including excellent blood compatibility, a lack of cytotoxicity, with no apparent rejection following implantation. STSCS exhibited rapid hemostasis and promoted healing, with slightly greater efficacy than DTSCS. The hemostatic properties and promotion of healing in DTSCS was similar to that of commercial bovine collagen sponge. Therefore, DTSCS and STSCS both represented excellent potential candidate materials for use as hemostatic agents and wound dressings.

Preparation of self-assembled collagen fibrillar gel from tilapia skin and its formation in presence of acidic polysaccharides

Fibrillar gel of pepsin-solubilized collagen from tilapia skin was prepared by self-assembly in neutral phosphate buffer at 28 °C. Then effects of acidic polysaccharides, such as sodium alginate (SA), chondroitin sulfate (CS), and hyaluronic acid (HA), on the formation and properties of self-assembled fibrillar gel were investigated. SA and CS prolonged gelling time, whereas HA had no obvious effect. SA made fibril network denser, while CS and HA induced the presence of larger ordered structures. All the acidic polysaccharides broadened the D-periodicity of fibrils. SA and HA increased the maximum mechanical strength of gel to 39.64 and 34.49 kN/m², respectively, significantly higher than that of pure collagen gel (14.53 kN/m²), while that only 17.20 kN/m² after CS introduced. HA had no evident effect on enzymatic resistance, while SA and CS decreased. Therefore, tilapia skin collagen with HA has a higher potential as a biomaterial than that with CS or SA.

Research status and development potential of composite hemostatic materials

Through the discussion of the coagulation mechanism of compositehemostatic materials, the future development potential of hemostatic materials is proposed.

Comprehensive assessment of Nile tilapia skin collagen sponges as hemostatic dressings

Nile tilapia skin collagen sponge was fabricated by lyophilization and cross-linked with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide in the presence of N-hydroxysuccinimide (EDC/NHS). The physicochemical properties were examined. The EDC/NHS cross-linked collagen sponge presented an enhanced water absorption capacity. In addition, biocompatibility and hemostatic efficiency were evaluated by acute systemic toxicity assay, dermal irritation test, intradermal reaction test, sensitization test, cytotoxicity, blood clotting assay in vitro, and liver and femoral artery hemorrhage models in vivo. Results showed that the produced collagen sponges before and after EDC/NHS cross-linking had excellent biocompatibility. Furthermore, EDC/NHS cross-linking promoted fibroblast cells viability and proliferation reflected by the MTT reduction assay. Meanwhile, EDC/NHS cross-linked collagen sponge exhibited the best blood clotting ability and hemostatic efficiency in rat femoral artery hemorrhage model in comparison with non-crosslinked and commercial collagen sponges. Our results demonstrated that the fabricated collagen sponges could be used as perfect hemostatic dressings.

Degradable and Bioadhesive Alginate-Based Composites: An Effective Hemostatic Agent

The perfect hemostatic material should be capable of rapidly controlling substantial hemorrhaging from visceral organs, veins, and arteries. Ideally, it should be biodegradable, biocompatible, easily applied, and inexpensive. Herein, taking advantages of sodium alginate (SA), carboxymethyl chitosan (CMC), and collagen, a degradable powdery hemostatic composite (SACC) was synthesized using emulsification and cross-linking technology. The morphology and structure of SACC were determined using Fourier transform infrared spectroscopy and scanning electron microscopy (SEM). This hemostatic material exhibited a typical generic sphere shape with narrow size distribution, rough surface, and satisfactory water absorption. Using in vitro bleeding and in vivo bleeding models (rat liver injury model and rat tail amputation model), it was shown that SACC had superior hemostatic actions compared to CMC and SA. Excellent cytocompatibility was proven during cytotoxicity tests and SEM observations. Histomorphological evaluation during the wound healing process proved the superior biocompatibility of SACC in a rat liver injury model. Biodegradability of SACC was demonstrated by immunofluorescence techniques both in vitro and in vivo. In summary, we have demonstrated the enormous potential of SACC, which has excellent hemostatic activity, biodegradability, and biocompatibility properties for use in clinical hemostasis applications.

Evaluation of biocompatibility and immunogenicity of micro/nanofiber materials based on tilapia skin collagen

Type I collagen, used as a raw material, plays a pivotal role in the development of medical devices and tissue engineering. Due to the risk of zoonotic transmission and religious constraints for mammalian collagen, fish collagen gains increased attention and is widely seen as an alternative. In this study, two collagen micro/nanofiber materials, self-assembled collagen nanofiber and electrospun collagen nanofiber, were prepared by tilapia skin collagen and their biocompatibility and immunogenicity was thoroughly investigated. The result revealed that the state of tilapia skin collagen in self-assembled collagen nanofiber and electrospun collagen nanofiber was different. The circular dichroism spectrum indicated that collagen in self-assembled collagen nanofiber retained the triple helical structure of the native collagen, while collagen in electrospun collagen nanofiber was denatured into gelatin. Nevertheless, the evaluation according to ISO10993, including tests of cytotoxicity, hemolysis, skin sensitization, acute systemic toxicity, mouse immunization and lymphocyte proliferation, demonstrated good biocompatibility and low immunogenicity for both self-assembled and electrospun collagen nanofiber materials. Overall, the present study highlighted that type I collagen from tilapia skin would be a promising biomaterial for the development of regenerate medical products.

Fabrication and characterization of Chinese giant salamander skin composite collagen sponge as a high-strength rapid hemostatic material

Chinese giant salamander (CGS) has high medicinal value and long history of clinical use in ancient China. In this study, CGS skin (CGSS) collagen was extracted and purified to prepare collagen sponge by freeze-drying. TEMPO oxidized microfibrillated cellulose (TEMPO-MFC) and genipin were adopted to improve the mechanical properties of collagen sponge. The hygroscopicity, porosity, mechanical properties, hemostatic performance, morphology, and biodegradability of the resultant sponges were investigated in detail. The results indicated that CGSS collagen was type I collagen with intact triple-helical structure, and the prepared sponge had porous structure and excellent hemostatic performance with procoagulant ratio of 53.28%. However, the CGSS collagen sponge showed low tensile strength (TS) of 98.80 KPa, compression strength (CS) of 1.48 KPa, and elongation at break (E) of 4.72%. Incorporating 2.5% TEMPO-MFC into the native CGSS collagen sponge resulted in an increase of 188.26% in TS to 284.80 KPa, 166.89% in CS to 3.95 KPa, and 73.52% in E to 8.19%. The improvements were attributed to the physical filling of TEMPO-MFC in cavity and cavity wall of collagen sponge and the stable chemical linkage between carboxyl of TEMPO-MFC and amino group of collagen which effectively improved the toughening of sponge and formed good interface bonding, respectively. Subsequent 0.3% genipin treatment further improved the TS to 605.00 KPa and the CS to 8.66 KPa as a result of crosslinking reaction. Moreover, the composite reinforcing also improved the anti-degradation ability and procoagulant ratio of collagen sponge. All results suggested that the TEMPO-MFC toughened and genipin crosslinked CGSS composite collagen sponge is a promising rapid hemostatic material with high-strength and can be applicated in biomedical field.

Physical properties and antioxidant activity of gelatin-sodium alginate edible films with tea polyphenols

Active edible films were prepared by incorporating tea polyphenols (TP) into gelatin and sodium alginate. The effects of 0.4%-2.0% TP (w/w, TP/gelatin) on physical, antioxidant, and morphological properties of gelatin-sodium alginate films were evaluated. Tensile strength (Ts), contact angle (CA), and cross-linking degree showed an enhanced trend as TP concentration in the film increased, whereas elongation at break (EAB) and water vapor permeability (WVP) possessed a decline trend. The light transmittance of the film was decreased by the incorporation of TP. Antioxidant capacity was improved by increasing TP content in the films. For DPPH and ABTS radical, the films with 2.0% TP possessed the highest values of 90.62 ± 2.48% and 53.36 ± 1.06 Trolox (mg Trolox equivalent/g film), respectively. Fourier transform infrared spectroscopy analyses (FTIR) indicated the interactions existed between gelatin‑sodium alginate and TP. Smooth and continuous surface and dense internal structure of the films with TP were observed by scanning electron microscopy (SEM). Thus, incorporating TP into gelatin and sodium alginate film solution was an effective method in order to improve physical properties and antioxidant activity of the films. Gelatin-sodium alginate films with TP could be used as an edible film for food packaging applications.