PROMISING COMPOSITE MATERIALS BASED ON NANOSCALE APATITE WITH GELATIN AS A BINDING AGENT

Порошки наноразмерных гидроксиапатита и фторапатита синтезированы методом осаждения из растворов. В качестве связующего вещества использован пищевой желатин. Такая композиция имеет высокую адгезию на материалах различной природы и пористости. Получены также пористые пленки и гранулы с развитой удельной поверхностью. Рассмотрены их микроструктуры. Изучена возможность использования коллоидной суспензии и водной суспензии кристаллического апатита в сочетании с раствором желатина в качестве биоактивного материала, как для создания покрытий, так и получения гранул. Установлено, что использование порошка апатита совместно с желатином позволяет существенно сократить сроки формирования биоактивного покрытия и значительно повысить его адгезионную прочность. Сопоставлены получаемые гранулы апатита по размерам в зависимости от концентрации желатина в водном растворе. На разработанные биоактивные покрытия и гранулированный материал на основе наноразмерного апатита со связующим агентом поданы заявки на патент. Nanoscale hydroxyapatite and fluorapatite powders were synthesized by precipitation from solutions. Food gelatin is used as a binder. This composition has a high adhesion on materials of different nature and porosity. Porous films and granules with a developed specific surface area were also obtained. Their microstructures are considered. The possibility of using a colloidal suspension and an aqueous suspension of crystalline apatite in combination with a gelatin solution as a bioactive material, both for creating coatings and obtaining granules, has been studied. It is established that the use of apatite powder together with gelatin can significantly reduce the time of formation of a bioactive coating and significantly increase its adhesive strength. The obtained apatite granules are compared in size depending on the concentration of gelatin in an aqueous solution. Patent applications have been filed for the developed bioactive coatings and granular material based on nanoscale apatite with a binding agent.

Effect of a 3% gelatin solution on urinary KIM-1 levels in patients after thyroidectomy: a preliminary randomized controlled trial

Optimal fluid therapy significantly affects the maintenance of proper tissue perfusion and, consequently, kidney function. An adverse effect of colloids on kidney function is related to the incidence of postoperative kidney failure. The study aimed to assess the effect of a 3% gelatin solution on kidney function based on the urinary kidney injury molecule-1 (uKIM-1) level. This study used a parallel design and enrolled 64 adult patients with a mean age of 52.5 ± 13.1 years, all of whom underwent a thyroidectomy procedure under general anesthesia. Patients were randomly assigned to three comparison groups, each receiving a different dose of 3% gelatin solution during the thyroidectomy procedure. The patients from study groups A (n = 21) and B (n = 21) received a 3% gelatin solution at a dose of 30 ml/kg and 15 ml/kg body weight, respectively, during the first hour of the procedure. The patients from the control group C (n = 22) received an isotonic multi-electrolyte solution. Serum creatinine levels were determined, and urine samples were collected to determine levels of uKIM-1 before, 2 h, and 24 h after surgery. The patients’ demographic data, type and volume of fluid and hemodynamic status during the surgery were collected from relevant anesthesia protocols and were included in the study data. There were no statistically significant changes between groups in hemodynamic parameters such as systolic and diastolic blood pressure, heart rate, and oxygen saturation values. A statistically significant increase in uKIM-1 level was noted in patients receiving the 3% gelatin solution regardless of the dose. A statistically significant difference in uKIM-1 level was observed between groups A, B, and C measured 24 h after surgery, with the highest uKIM-1 level in group A. Measurement of uKIM-1 level could be an early and sensitive biomarker of kidney injury. Kidney toxicity of a 3% gelatin solution, evaluated based on the level of uKIM-1 in urine, correlates with transfused fluid volume. This study was retrospectively registered in the ISRCTN clinical trials registry (ISRCTN73266049, 08/04/2021: https://www.isrctn.com/ISRCTN73266049).

Effects of transglutaminase cross-linking process on printability of gelatin microgel-gelatin solution composite bioink

Three-dimensional (3D) bioprinting has emerged as a powerful engineering approach for various tissue engineering applications, particularly for the development of 3D cellular structures with unique mechanical and/or biological properties. For the jammed gelatin microgel-gelatin solution composite bioink, comprising a discrete phase of microgels (enzymatically gelled gelatin microgels) and a cross-linkable continuous gelatin precursor solution-based phase containing transglutaminase (TG), its rheology properties and printability change gradually due to the TG enzyme-induced cross-linking process. The objective of this study is to establish a direct mapping between the printability of the gelatin microgel-gelatin solution based cross-linkable composite bioink and the TG concentration and cross-linking time, respectively. Due to the inclusion of TG in the composite bioink, the bioink starts cross-linking once prepared and is usually prepared right before a printing process. Herein, the bioink printability is evaluated based on the three metrics: injectability, feature formability, and process-induced cell injury. In this study, the rheology properties such as the storage modulus and viscosity have been first systematically investigated and predicted at different TG concentrations and times during the cross-linking process using the first-order cross-linking kinetics model. The storage modulus and viscosity have been satisfactorily modeled as exponential functions of the TG concentration and time with an experimentally calibrated cross-linking kinetic rate constant. Furthermore, the injectability, feature formability, and process-induced cell injury have been successfully correlated to the TG concentration and cross-linking time via the storage modulus, viscosity, and/or process-induced shear stress. By combing the good injectability, good feature formability, and satisfactory cell viability zones, a good printability zone (1.65, 0.61, and 0.31 hours for the composite bioinks with 1.00, 2.00, and 4.00% w/v TG, respectively) has been established during the printing of mouse fibroblast-based 2% gelatin B microgel-3% gelatin B solution composite bioink. This printability zone approach can be extended to the use of other cross-linkable bioinks for bioprinting applications.

Interaction between Gelatin and Nano-Silver Particle: Foundation for Nano-Silver in Antibacterial Leather

In order to explain the interaction between collagen and nano-silver, gelatin solution was blended with nano-silver particles (AgNPs) with particle size 26 mm, and then the mixture was interacted under different time, pH and temperature. The changes in the process were measured by UV-Vis, fluorescence spectroscopy, dynamic light scattering and FT-IR. The results showed that the main type of reaction between gelatin and AgNPs was electrostatic interaction and the interaction was diffusive encounters. The particle size and distribution of nano-silver would not be affected by gelatin, however, there was dynamic fluorescence quenching of gelatin after nano-silver particle induced. The longer time and lower pH were beneficial for the interaction process while the interaction balanced after 60 min and pH 3.0 resulted in the most drastic interaction. Moreover, nano-silver would not impair gelatin structure during the interaction process. In short, the results in this work might be a foundation and reference for applying nano-silver in antibacterial leather producing.

Morphometric traits of selected heart veins of standard and mutational colour variants of American mink (Neovison vison)

The aim of the study was to estimate the values of metric traits of selected mink heart veins of standard and mutation colour variants. The study was conducted on 342 hearts of seven-month-old males and 405 hearts of seven-month-old females. Mink colour, resulting from mutation or from crossbreeding mutational colour variants with each other. Metric traits of the coronary sinus, great cardiac vein, middle cardiac vein, posterior vein, and small cardiac vein were determined by photographic recording of the sub-epicardial picture of these vessels after filling them with a water-dilutable dye for acrylic paints together with a 30% food gelatin solution. In addition, the number of the veins forming the great cardiac vein and that of the posterior veins of the left ventricle were determined. Based on the measurement of the width and length of the mink hearts, the heart shape was determined. Differences were found between the traits of the mink heart vessels of standard and mutational colour variants, but they did not allow to formulate clearly the thesis about the effect of mutations on these traits.

Hemodynamic efficacy and safety of using modified gelatin solution and polyhydric alcohol solution for fluid resuscitation of patients with septic shock

Objective ‒ to compare the hemodynamic effects and safety of the infusion of succinylated gelatin solution, sorbitol-containing solution, and 0.9 % normal saline (0.9 % sodium chloride), analyze their effect on the treatment of septic shock and mortality.Materials and methods. A prospective randomized clinical trial that included 94 adult patients with an active surgical infection and septic shock was conducted. There were 34 (36.2 %) male and 60 (63.8 %) female patients aged between 19 and 96 years, mean age was (66.51 ± 17.06) years. An appropriate solution in a volume of 500 ml was used for resuscitation, then hemodynamic and other clinical and laboratory parameters were monitored.Results. There was no significant difference in mean arterial pressure (MAP) between the 3 groups until the 40th minute (p>0.05). At the 45th minute MAP in the NS group differed only from MAP in the Gel group (p=0.007). At the 50th minute MAP in the NS group did not differ from the baseline (p=0.139). From the 50th minute to 2 hours, MAP in the Gel and Sorb groups was higher than in the NS group in all measurements (p<0.05). There was no statistically significant difference in heart rate (HR) in any measurement (p>0.05). Cardiac output (CO) did not differ up to the 30th minute (p>0.05), at the 35th minute, CO differed only between Gel and NS groups (p=0.019), from the 40th minute to 2 hour CO in Gel and Sorb groups were significantly higher than in NS group in all measurements (p<0.05). Oxygen delivery (DO2) also did not differ up to the 30th minute (p>0.05), from the 35th minute to the 45th minute a significant difference was found only between Gel and NS groups (p<0.05), from the 50th minute to 2 hour DO2 in Gel and Sorb group was significantly higher than in NS group in all measurements (p<0.05). After infusion of the gelatin-containing solution and sorbitol-containing solution, the acid-base balance of the blood improved significantly. The dose of gelatin-containing and sorbitol-containing solutions applied in this study was safe for the renal function of the patients with septic shock. However, it is possible that a decrease in blood fibrinogen concentrations may be associated with the use of a gelatin-containing solution. Significant improvement in the Glasgow Coma Scale scores was observed only in patients in the group receiving the sorbitol-containing solution. The difference in 28-day mortality between the groups was not statistically significant (p=0.993).Conclusions. In our observations, when using these three types of solution in patients with septic shock, hemodynamic effects up to the 40th minute did not differ between groups. From the 40th minute to 2 hour, the volemic effect of 4 % succinylated gelatin solution and balanced polyionic solution with 6 % sorbitol was significantly better, compared to the 0.9 % sodium chloride solution. The volume of solutions used in these three groups did not affect renal function in patients with septic shock. The amount of balanced polyionic solution used with 6 % sorbitol and 0.9 % sodium chloride solution did not affect blood coagulation function. But the use of 4 % succinyl gelatin solution reduced the concentration of fibrinogen in the blood. After infusion of the gelatin-containing solution with buffer formulations and sorbitol-containing solution with buffer formulations, the acid-base status of the blood was significantly improved compared to 0.9 % sodium chloride solution. Infusion of the gelatin-containing solution and 0.9 % sodium chloride solution did not affect the Glasgow coma score in patients. After infusion of the sorbitol-containing solution, patients’ consciousness was improved by this scale. The 28-day mortality did not differ significantly between groups.

Effect of pH and water irradiation with the electromagnetic field on the gelation of gelatin solutions

The rate of gelation was determined from the curve slope of the dependence of the gelatin solution relative viscosity on time at different pH. It was found that slow gelation of 2 % gelatin solution occurs at T = 293 K, and the degree of fluidity significantly depends on рН. The most stable jellies are formed at the isoelectric point (рН = 4.7). There are significant differences in the physical state of jellies prepared on irradiated water and control samples. Prepared on unirradiated water jellies are more mobile and retain fluidity at T = 293 K regardless of рН. There is a partial or full melting of the jellies with the increase in temperature at 297 K; however solid state remains for irradiated systems at pH = 4 and 4.7. It was shown that the viscosity of the ir-radiated solution and the rate of its increase are higher in comparison with the control samples at all pH val-ues except рН = 2. The observed phenomenon can be caused by the weakening of the hydration of polymer macromolecules in the activated water, which facilitates their association and the formation of a structured system.

A Comparison of Two Gelatin Consolidants for the Preservation of Thermally Altered Skeletal Remains

A recent study (Topoleski & Christensen 2019) found that applying a food-grade gelatin solution to thermally altered skeletal remains resulted in significantly better structural preservation (reduced fragmentation) during recovery and transport compared to untreated controls. Here we expand upon this research and test whether a technical-grade gelatin would result in even better skeletal evidence preservation. Results show that bones treated with both the food-grade and technical-grade gelatins were better preserved (i.e., had less fragmentation) than untreated controls. Application of the technical-grade gelatin, however, did not result in significantly better preservation than the food-grade gelatin, and is less accessible, more expensive, and more difficult to prepare. Food-grade gelatin is therefore recommended, but other types of gelatins can be equally effective.