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Synthesis and characterization of glutaraldehyde-based crosslinked gelatin as a local hemostat sponge in surgery: Anin vitrostudy
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In this study, preparation and characterization of soft crosslinked gelatin sponge for blood hemostasis application was considered. The effects of gelatin and crosslinker concentrations and altering freeze-drying temperature on sponges' density and structure, water absorption ability and biodegradation, cytotoxicity, mechanical properties and hemostatic effect were investigated. The density measurement indicated that the density of freeze-dried sponges increased when the freezing temperature was lowered. Scanning electron microscope and optical microscope images showed that gelatin sponges had uniform small pores (60 µm) after freezing at liquid nitrogen (−196 • C). Biodegradation study demonstrated that the crosslinked sponges containing 1% and 2% gelatin lost respectively nearly 40 to 70% of their weight during 24 h. Prepared sponges showed desired water absorption ability (30–40 times of own dry weight) improved by lowering glutaraldehyde concentration. Cell toxicity was not detected in any of the samples. Compression modulus of sponges decreased four times (160 to 40 kPa) as the gelatin content varied from 2 to 1% w/v. Hemostasis study confirmed that the hemolytic ability of sponges increased through raising gelatin content and porosity of sponge. We suggest using gelatin sponges containing 1% w/v gelatin, 0.5% w/v glutaraldehyde frozen in liquid nitrogen, as a potential substitution for local hemostat absorbable sponge.
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... Gelatin, derived from denatured collagen, has also been shown to act as a physical barrier to blood flow both by swelling and by bonding with the surface of a wound (Imani et al., 2013 (Hajosch et al., 2010). One of the drawbacks of gelatin is that it has been found to be a cause of mass lesions (Tomizawa, 2005 Similarly, microfibrillar collagen hemostats like Avitene are a subgroup of gelatinbased hemostats. ...
Hemorrhage is the leading cause of preventable death after a traumatic injury. Commercial hemostatic agents exist, but have various disadvantages including high cost, short shelf-lives, or secondary tissue damage. Polymer hydrogels provide a promising platform for the use of both biological and mechanical mechanisms to accelerate natural hemostasis and control hemorrhage. The goal of this work was to develop hydrogel particles composed of chitosan and alginate and loaded with zeolite in order to stop blood loss by targeting multiple hemostatic mechanisms. Several ii particle compositions were synthesized and then characterized through swelling studies, particle sizing, Scanning Electron Microscopy (SEM), and Fourier Transform Infrared Spectroscopy (FTIR). The in vitro interactions of the particles were evaluated through coagulation, degradation, platelet aggregation, and cytotoxicity studies. The results indicate that 4% alginate, 1% chitosan, 4% zeolite-loaded hydrogel beads can significantly reduce time to coagulation and increase platelet aggregation in vitro. Future research can look into the efficacy of these particles in vivo.
In this study, preparation and characterization of soft crosslinked gelatin sponge for blood hemostasis application was considered. The effects of gelatin and crosslinker concentrations and altering freeze-drying temperature on sponges' density and structure, water absorption ability and biodegradation, cytotoxicity, mechanical properties and hemostatic effect were investigated. The density measurement indicated that the density of freeze-dried sponges increased when the freezing temperature was lowered. Scanning electron microscope and optical microscope images showed that gelatin sponges had uniform small pores (60 μm) after freezing at liquid nitrogen (-196°C). Biodegradation study demonstrated that the crosslinked sponges containing 1% and 2% gelatin lost respectively nearly 40 to 70% of their weight during 24 h. Prepared sponges showed desired water absorption ability (30-40 times of own dry weight) improved by lowering glutaraldehyde concentration. Cell toxicity was not detected in any of the samples. Compression modulus of sponges decreased four times (160 to 40 kPa) as the gelatin content varied from 2 to 1% w/v. Hemostasis study confirmed that the hemolytic ability of sponges increased through raising gelatin content and porosity of sponge. We suggest using gelatin sponges containing 1% w/v gelatin, 0.5% w/v glutaraldehyde frozen in liquid nitrogen, as a potential substitution for local hemostat absorbable sponge.
Blood compatibility is dictated by the manner in which their surfaces interact with blood constituents like RBCs, WBCs, platelets and blood proteins. The aim of this study was to investigate the effect of surface free energy and the corresponding work of adhesion of biomaterial surfaces on such interactions. Hydroxyapatite and AW glass ceramics, whose properties and gradations in bio compatibility are well established, were chosen for analysis. Work of adhesion of erythrocytes and platelets on to these surfaces, in aqueous solutions, were determined from contact angles with three standard liquids. Glass was used as control in these experiments because of its well-documented properties. The work of adhesion was lower for AW glass ceramics (-36.1 mJ/m2 for erythrocytes and -47.4 mJ/m2 for platelets) and Hydroxyapatite (-44.9 mJ/m2 for erythrocytes and -41.9 mJ/m2 for platelets), suggesting that these would lead to a lesser extent of cell adhesion when exposed to blood. The corresponding values for Glass were 13.6 mJ/m2 for erythrocytes and 35.6 mJ/m2 for platelets, which suggests that maximum red cell and platelet adhesion would occur on glass. Spectrophotometry and platelet aggregometry were used to assess the damage caused to the RBC and platelet membranes following exposure of these cells to these biomaterials. Absorbance was measured at 540 nm to quantify the hemoglobin released in order to estimate the extent of red cell lysis. The absorbances of blood samples (following exposure to various biomaterials) were normalized with that of control blood. At a Sodium Chloride concentration of 0.18%, Hydroxyapatite exhibited a value of 1.1 on the normalized scale (similar to that of control) while AW glass ceramics exhibited a value of 1.8 (almost twice that of control). Glass exhibited the maximum value of absorbance (2.4) suggesting that exposure to glass has resulted in maximum lysis. Glass exposure also resulted in the maximum change in platelet aggregation. These results are in agreement with the results interpreted from the work of adhesion of erythrocytes and platelets on to these materials. The number of adhered platelets on the biomaterial surfaces following incubation in Platelet Rich Plasma was also studied using environmental Scanning Electron Microscopy. Glass surface exhibited the maximum number of adhered platelets. In summary, the surface free energy of biomaterials and the corresponding values of work of adhesion can be used as characterization parameters for predicting cell adhesion on to their surfaces and hence for establishing their blood compatibility.
Bioadhesives are used for tissue adhesion and hemostasis in surgery. A gelatin-resorcinol mixture crosslinked with formaldehyde (GRF glue) and/or glutaraldehyde (GRG) is used for this purpose. Although the bonding strength of the GRF glue to tissue is satisfactory, concerns about the cytotoxicity of formaldehyde are reported in the literature. It was suggested that the cytotoxicity problem of the GRF glue may be overcome by changing its crosslinking method. The study was therefore undertaken to assess the feasibility of using an epoxy compound (GRE glue), a water-soluble carbodiimide (GAC glue), or genipin (GG glue) to crosslink with a gelatin hydrogel as new bioadhesives. GRF glue and GRG glue were used as controls. The results of our cytotoxicity study suggested that the cellular compatibility of the GAC and GG glues was superior to the GRF, GRG, and GRE glues. The gelation time for the GG glue was relatively longer than the GRF and GRG glues, while no gelation time could be determined for the GAC glue. Additionally, it took approximately 17 h for the GRE glue to become adhesive. The GRF and GRG glues had the greatest bonding strengths to tissue among all test adhesives, while the bonding strengths of the GAC and GG glues were comparable. In contrast, there was almost no bonding strength to tissue for the GRE glue, However, the GRF and GRG glues were less flexible than the GAC and GG glues. Subsequent to the bonding strength measurement, each test adhesive was found to adhere firmly to the tissue surface and underwent cohesive failure during the bond breaking. In conclusion, the GRF and GRG glues may be used as tissue adhesives when their ability to bind tissue rapidly and tightly is required; the GAC and GG glues are preferable when the adhesive action must be accompanied with minimal cytotoxicity and stiffness; and the GRE glue is not suitable for bioadhesion in clinical applications. (C) 1999 John Wiley & Sons, Inc.
The problems linked to blood loss and blood-sparing techniques in spine surgery have been less studied than in other fields of orthopedics, such as joint-replacement procedures. Decreasing bleeding is not only important for keeping the patient's hemodynamic equilibrium but also for allowing a better view of the surgical field. In spine surgery the latter aspect is especially important because of the vicinity of major and highly fragile neurologic structures. The techniques and agents used for hemostasis and blood sparing in spinal procedures are mostly similar to those used elsewhere in surgery. Their use is modulated by the specific aspects of spinal approach and its relation to the contents of the spinal canal. Blood-sparing techniques can be divided into two categories based on their goals: either they are aimed at decreasing the bleeding itself, or they are aimed at decreasing the need for homologous transfusion. Various hemodynamic techniques, as well as systemic and local drugs and agents, can be used separately or in combination, and their use in the field of spine surgery is reported. The level of evidence for the efficacy of many of those methods in surgery as a whole is limited, and there is a lack of evidence for most of them in spine surgery. However, several blood-saving procedures and drugs, as well as promising new agents, appear to be efficient, although their efficacy has yet to be assessed by proper randomized controlled trials.
Gelatin and collagen were used to produce the scaffold for fibroblast cell culture. The properties of scaffolds obtained from type A and type B gelatin were compared to scaffold obtained from collagen, which is widely used in skin substitute. Porous scaffolds were prepared by freeze drying and dehydrothermal (DHT) crosslinking method. DHT treatment time was performed at 24 and 48 h and the degree of crosslinking was determined by 2,4,6-trinitrobenzene sulphonic acid (TNBS). The morphology of scaffolds was investigated by scanning electron microscopy (SEM). The compressive modulus and swelling ratio of the scaffolds were reported. To confirm the applicability of the scaffolds as a skin substitute, in vitro cell adhesion and cell proliferation tests were employed in this study. The gelatin scaffolds showed comparable properties, especially cell proliferation, to those of collagen scaffolds but the rapid degradation rate of gelatin was the limiting factor of using gelatin in wound healing. However, gelatin scaffolds could be modified to reduce the degradation rate and used substitute collagen scaffold to reduce the cost of materials for scaffold fabrication.
Chemical and mechanical experiments are reported to elucidate the macroscopic effects of crosslinker length and composition on the thermomechanical response of acrylate‐based SMPs. To this end, EGA‐based formulations underwent a battery of basic tests which revealed that by increasing crosslinker chain length, polymer T g can be decreased but there will be increases in compliance, step recoverability, and damping in a glassy state. Addition of methacrylate groups can cause increases in swelling, T g , storage modulus in shorter chains, and greater damping at a rubbery state. All tested polymers exhibited mild hydrophilicity. PEGDA formulations exhibited good recoverability and could be an option for vascular applications.
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The water sorption behaviour of several cross-linked gelatin-based systems were investigated and compared. The systems were
gelatin, gelatin/ethyleneglycol, gelatin/polyoxypropylenediamine, and gelatin/polyethylene oxide. For all the systems, an
increased water gain was obtained by raising the concentration of the second component, while the swelling was reduced by
an increase of the cross-linking density.
Gelatins extracted from the skins containing fine scales of two species of bigeye snapper, Priacanthus tayenus (GT) and Priacanthus macracanthus (GM), were characterised. Both gelatins had the protein as the major component with high content of imino acids (proline & hydroxyproline) (186.29–187.42 mg/g). GT and GM contained calcium at levels of 6.53 and 2.92 g/kg, respectively. Both gelatins contained α1 and α2 chains as the predominant components and some degradation peptides. The absorption bands of both gelatins in Fourier transform infrared (FTIR) spectra were mainly situated in the amide band region (amide I and amide II). GT and GM had a relative solubility greater than 90% in the wide pH ranges (1–10). The bloom strength of GM (254.10 g) was higher than that of GT (227.73 g) (P < 0.05), but was slightly lower than that of commercial bovine gelatin (293.22 g) (P < 0.05). Finer gel structure with smaller strands and voids was observed in GM gel, in comparison with that observed in GT counterpart.
The aim of this study, is synthesis of an absorbable hemostat gelatin sponge crosslinked with 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC). The effects of various gelatin contents and crosslinking agent concentrations, freezing temperature on the mechanical properties, rate of biodegradation in 24 h, hemolytic ability and cell viability of sponges were investigated. The results of scanning electron microscopy (SEM) showed that freezing temperature had a significant effect on the structure and density of sponges. SEM views of the sponges demonstrated that they have pores with mean diameters of 180–280 μm. Fourier transform infrared (FTIR) spectra indicated that there is no residual of the crosslinking agent in the structure of final gelatin sponges because of C–N bonds (urea derivatives) absence. The sample with 1% gelatin and 0.05% EDC freezed at −25 °C (before freeze-drying) showed more than 0.37 cm−1 UV absorption of hemoglobin or blood clotting in half an hour. The compression modulus of the same sample was more than 150 kPa and percentage of degradation was about 28% in 24 h.
Gelatin-hyaluronate sponge with and without antibiotic and epidermal growth factor (EGF) were prepared and compared. Four types of sponges were applied on the full-thickness dorsal skin defect of Wistar rat. The effects of antibiotic and EGF in gelatin-hyaluronate sponge on wound healing were investigated by light microscopy and image analyzer at postoperative days of 5, 12 and 21. An immunohistochemical technique, employing PC10, a monoclonal antibody against proliferating cell nuclear antigen (PCNA) was applied to wounded tissue sections. The number of PC10-positive cells was very high for the sponge with EGF at postoperative day 5, then gradually decreased with time. Also we found that antibiotics restrained the cell proliferation during the migratory phase. The sponge with both antibiotic and EGF showed good wound healing performances on the whole for a healing period. The epithelium was regenerated fast with EGF-impregnated sponges at day 5, but each sample had nearly the same length of regenerated epithelium at day 12.