Irradiated Gelatin Research Articles

Temperature-Dependent Changes in Gamma Irradiated Porcine Gelatin with Low Bloom (PGL) Value: an ESR Investigation

Gamma irradiation of Gelatin brings important changes in its chemical structure, making it suitable for different applications. The irradiated Gelatin may be subjected to different thermal treatments during these applications. Therefore, temperature-dependent changes in irradiated gelatins are a point of interest. Electron spin resonance (ESR) is vital for detecting free radical processes in irradiated polymers. As such, ESR spectra of temperature-dependent porcine Gelatin with low bloom are recorded, and they are analyzed by computer simulation techniques. Component spectra under different conditions are evaluated by the magnetic parameters employed to simulate the ESR spectra. The results indicate that the spectral shape at 300 K (RT) is stable up to 350 K, and signal intensity begins to decay beyond 350 K. The signal vanished around 355 K, designated as radical decay temperature. Bloch analysis is applied to evaluate activation energy associated with free radical decay, calculated around 35 KJ/mole.

Effect of gamma irradiation, annealing on spectroscopic and thermal properties of some biopolymers – Gelatin

Modification of chemical structure of gelatin is an important point of research due to its extensive applications in food and package industry. Various methods are prescribed in literature for this purpose. Among them the radiation method is very important due to its easiness and economy. The authors have used gamma irradiation for this purpose and studied the effect of gamma irradiation and annealing on spectroscopic and thermal properties of gelatins. For this purpose spectroscopic (Electron spin resonance (ESR) and Fourier transform infrared (FTIR)), thermal (differential scanning calorimetry) and scanning electron microscope are used. ESR spectra of irradiated gelatin have shown quartet structure at room temperature and the signal is annealed by heating the irradiated gelatin. FTIR spectra of gelatin are recorded under different conditions. After irradiation, change in intensity and shift in band position is observed, which are associated with the chemical changes brought out by radiation. Gamma irradiation brings changes in thermal and surface morphology of gelatin.

181 Establishment of Induced Pluripotent Stem Cells from Fishing Cat and Clouded Leopard Using Integration-Free Method for Wildlife Conservation

Fishing cat (Prionailurus viverrinus) and clouded leopard (Neofelis nebulosa) are wild felids, currently in vulnerable status according to the International Union for Conservation of Nature red list (2017). Several measures in assisted reproductive technology (e.g. AI, embryo transfer) have been used by the Zoological Park Organization of Thailand (ZPO) to increase their offspring in captivity. Recently, the generation of induced pluripotent stem cell (iPS cells) becomes popular and provides alternative way to preserve good genetics in the form of cell with diverse capacities. This great potential of iPS cells is unlimited self-renewal and pluripotency, similar to embryonic stem cells (ESC). Under the right cell culture conditions, pluripotent stem cells can differentiate into all cell types of the body. Here, we aimed to find the optimal condition to generate integration-free iPS cells from fishing cat and clouded leopard. At first, to obtain somatic cells for cellular reprogramming, adult dermal fibroblast cell lines from both species were established from belly skin tissues. Subsequently, several nucleofection programs of AmaxaTM 4D-nucleofectorTM (Lonza, Basel, Switzerland) were examined to introduce integration-free DNA vectors carrying reprogramming factors into the felid fibroblasts. The transfected cells were cultured under numerous conditions: (1) matrix/defined surface including irradiated mouse embryonic fibroblast, gelatin, vitronectin, and Geltrex® (Thermo Fisher Scientific, Waltham, MA, USA); (2) ESC/iPS cell medium including Essential 8TM (Thermo Fisher Scientific) DMEM containing KnockOutTM Serum Replacement (KOSR; Thermo Fisher Scientific) and/or fetal bovine serum (FBS); and (3) supplement including basic fibroblast growth factor (bFGF), leukemia inhibitory factor (LIF), l-ascorbic acid, nicotinamide, ALK5 inhibitor (A83-01) and RevitaCellTM (Thermo Fisher Scientific). We found that optimal nucleofection programs for human dermal fibroblast including FF-135 and EN-150 were able to transfer episomal vectors and excisable piggyBAC transposon carrying reprogramming factors into fishing cat and clouded leopard fibroblasts, respectively. The iPS-like colonies appeared around 26 to 30 days post-nucleofection. The culture of transfected cells on either Geltrex® or Vitronectin-coated surface supports the formation of iPS-like colonies with different derivation efficiency (0.01 and 0.005%, respectively). In addition, all colonies were formed under medium containing FBS, together with both bFGF and LIF supplements. Taken together, we have developed a platform to generate iPS cells from tissue collection to the establishment of iPS cell culture. This will further enable us to apply the technique to obtain iPS cells from other endangered and vulnerable felid species.

Micropatterning of reagent-free, high energy crosslinked gelatin hydrogels for bioapplications.

Hydrogels are crosslinked polymeric gels of great interest in the field of tissue engineering, particularly as biocompatible cell or drug carriers. Reagent-free electron irradiated gelatin is simple to manufacture, inexpensive and biocompatible. Here, the potential to micropattern gelatin hydrogel surfaces during electron irradiation crosslinking was demonstrated as a promising microfabrication technique to produce thermally stable structures on highly relevant length scales for bioapplications. In the present work, grooves of 3.75 to 170 µm width and several hundred nanometers depth were transferred onto gelatin hydrogels during electron irradiation and characterized by 3D confocal microscopy after exposure to ambient and physiological conditions. The survival and influence of these microstructures on cellular growth was further characterized using NIH 3T3 fibroblasts. Topographical modifications produced surface structures on which the cultured fibroblasts attached and responded by adapting their morphologies. This developed technique allows for simple and effective structuring of gelatin and opens up new possibilities for irradiation crosslinked hydrogels in biomedical applications in which cell attachment and contact guidance are favored. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 320-330, 2018.

Cellular Response to Reagent-Free Electron-Irradiated Gelatin Hydrogels.

As a biomaterial, it is well established that gelatin exhibits low cytotoxicity and can promote cellular growth. However, to circumvent the potential toxicity of chemical crosslinkers, reagent-free crosslinking methods such as electron irradiation are highly desirable. While high energy irradiation has been shown to exhibit precise control over the degree of crosslinking, these hydrogels have not been thoroughly investigated for biocompatibility and degradability. Here, NIH 3T3 murine fibroblasts are seeded onto irradiated gelatin hydrogels to examine the hydrogel's influence on cellular viability and morphology. The average projected area of cells seeded onto the hydrogels increases with irradiation dose, which correlates with an increase in the hydrogel's shear modulus up to 10 kPa. Cells on these hydrogels are highly viable and exhibits normal cell cycles, particularly when compared to those grown on glutaraldehyde crosslinked gelatin hydrogels. However, proliferation is reduced on both types of crosslinked samples. To mimic the response of the hydrogels in physiological conditions, degradability is monitored in simulated body fluid to reveal strongly dose-dependent degradation times. Overall, given the low cytotoxicity, influence on cellular morphology and variability in degradation times of the electron irradiated gelatin hydrogels, there is significant potential for application in areas ranging from regenerative medicine to mechanobiology.

Electrical impedance response of gamma irradiated gelatin based solid polymer electrolytes analyzed using a generalized calculus formalism

The electrical impedance response of gelatin based solid polymer electrolyte to gamma irradiation is investigated by impedance spectroscopy. An analysis based on Poisson–Nernst–Plank model, incorporating fractional time derivatives is carried out. A detailed derivation for anomalous impedance function is given. The model involves boundary conditions with convolution of the fractional time derivative of ion density and adsorption desorption relaxation kinetics. A fractional diffusion–drift equation is used to solve the bulk behavior of the mobile charges in the electrolyte. The complex adsorption–desorption process at the electrode–electrolyte interface produces an anomalous effect in the system. The model gives a good fit for the observed impedance data for this biopolymer based solid electrolyte in a wide range of frequencies. We have compared different parameters based upon this model for both irradiated and unirradiated samples.

Gamma-Irradiated Gelatin-Based Films Modified by HEMA for Medical Application

The present article describes the synthesis and characterization of bi-component polymer systems based on gelatin films incorporated with 2-hydroxyethyl methacrylate (HEMA) monomer, developed for medical application. Gelatin films were prepared by the addition of HEMA of different concentrations (0–30 wt.%) and irradiated with various radiation doses (0–5 kGy). Tensile strength and tear strength of the irradiated gelatin films were found to increase with increasing HEMA up to 20 wt.% as well as radiation doses (1 kGy) as optimized. The maximum tensile and tear strengths of irradiated gelatin films with HEMA were found to be 79.1 MPa and 83.2 N/mm, respectively, at the optimum conditions, and these values were about double that of a reference film prepared without additives. In addition, morphological analysis was done by scanning electron microscopy (SEM) and showed how HEMA cemented and was covered with gelatin in the blend. Thermomechanical analysis was carried out to investigate the shifting of glass transition temperature (Tg) towards higher temperature due to HEMA addition, and the effect of this film was tested on the human body in order to determine whether it can be applied for medical purposes.

Physico-chemical characteristics of gamma-irradiated gelatin.

This article reports the effects of gamma irradiation (dose ranges 0.1–10 kGy from 60Co source) on the characteristics of solid gelatin and the physico-mechanical, microstructural and bioactive properties of the scaffold prepared from irradiated gelatin solution. FTIR, intrinsic viscosity, bloom strength, thermal properties, SEM, tensile properties, water uptake ability and antimicrobial activities of non-irradiated and irradiated solid gelatin and its scaffolds were investigated. The detailed experimental results for the solid gelatin demonstrated that 1 kGy γ-irradiated samples showed higher intrinsic viscosity, enhanced thermal stability and bloom strength than other irradiated samples. Furthermore, the scaffold thus prepared from irradiated and non-irradiated gelatin also revealed that 1 kGy samples showed the highest tensile strength and modulus with good water resistivity than other irradiated and non-irradiated samples. In addition to the physico-mechanical properties, 1 kGy scaffolds have also exhibited the highest resistivity towards microbial growth that can have potentiality as scaffold in biomedical sector. The enhanced functional and bioactive properties at low irradiation doses (1 kGy) may occurred due to an initial breaking of hydrogen bonds of polypeptide chains in gelatin molecules that indicated by the shift of amide A, I and II peaks to higher wave numbers in FTIR. This enhancement resulted probably due to the domination of crosslinking over degradation at 1 kGy. It was also observed that 1 kGy γ-radiation-induced crosslinking has lowered the hydrophilicity by decreasing water uptake and mean pore diameter of the interconnected porous structures of gelatin.

Effect of Gamma Irradiation on Mechanical and Thermal Properties of Fish Gelatin Film Isolated from <i>Lates Calcarifer</i> Scales

The objective of this research was to investigate the effect of gamma irradiation on mechanical and thermal properties of fish gelatin films prepared from scales of Lates calcarifer. The films were irradiated by gamma rays at varied doses (0-50 kGy). The mechanical and thermal properties of irradiated gelatin films were measured by using colorimeter, Universal Testing Machine, Differential Scanning Calorimetry (DSC), and Fourier Transform Infrared (FTIR) spectrophotometer. The results showed that increasing of irradiation dose up to 50 kGy, the color of irradiated film did not change significantly (p < 0.05). The tensile strength of irradiated film was increased with no differences among dose variation but there was no change on elongation at break value (p < 0.05). The DSC spectra of irradiated gelatin films showed that irradiation did not affect melting temperature (Tm). In contrast, the glass transition temperature (Tg) of irradiated film has slight tendency to increase with increasing of radiation doses. In general, the FTIR spectra confirmed that gamma irradiation up to 50 kGy affected the mechanical properties of gelatin films.

Preparation and characterization of polyethylene oxide (PEO)/gelatin blend for biomedical application: Effect of gamma radiation

Abstractpolyethylene oxide (PEO)/gelatin blend membranes of four different compositions (w/w) (5/95, 10/90, 20/80, and 30/70) were prepared by solution casting. The films were irradiated by gamma radiation at a total dose of 250 krad (dose rate of 321 krad/h). The X‐ray diffractograms demonstrate both the PEO and radiation influences on the blend thus enhancing crystallinity of gelatin. X‐ray diffractograms of irradiated blend films containing 30% PEO showed highest integrated intensity. The DTA and TGA study showed that the irradiated blend films are more thermally stable than the non‐irradiated films. TMA study showed that the incorporation of PEO into gelatin increased melting point of the blend films. The melting point for irradiated gelatin film changes from 52.9°C to 75.6°C and the glass point changes from 60.3°C to 90.6°C. The phase separation and compatibility of the PEO/gelatin blend films were studied by scanning electron microscopy (SEM). The experimental results showed that the blend films exhibit higher thermal stability and improved mechanical properties in dry state, which suggests the occurrence of interaction detected by XRD and DTA among gelatin, PEO, and water molecules in the films. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Radiation-Induced Cross-Linking of Gelatin by Using γ-Rays: Insoluble Gelatin Hydrogel Formation

Abstract Gelatin hydrogels with various concentrations were cross-linked by the irradiation with 60Co γ-rays, and we investigated the radiation-induced cross-linking of gelatin hydrogels by estimating the physical properties of irradiated hydrogels. In case of the 1, 5, and 10% (w/v) gelatin solutions, the specific water content of the irradiated hydrogels, the index showing the extent of cross-linking depended on the absorbed dose, and that of the irradiated gelatin hydrogels with the lower concentration decreased drastically. The breaking strength correlated to the absorbed dose, irrespective of the initial gelatin concentration. More than 8 kGy irradiation induced insolubility due to the cross-linking of the gelatin hydrogels. Besides, γ-ray irradiation to gelatin with free amino acids revealed that amino acids, which have side chains of hydrocarbon groups that are more than two carbon atoms, obstructed the cross-linking of gelatin hydrogels. It is thought that the hydrocarbon groups, such as an alkyl or a phenyl group of the side chains, are the cross-linking sites of gelatin hydrogels.

Observation of Dynamic Absorption Properties of Wet Gelatin around λ=6.05 µm Using a Mid-Infrared Free Electron Laser

It is essential for soft tissue cutting to precisely predict the effects of laser irradiation before treatment. The purpose of the present study was to investigate the dynamic absorption coefficients of wet gelatin around λ=6.05 µm (tuned to the OH bending and amide-I bands) during laser irradiation. Wet gelatin was irradiated by a tunable mid-infrared free electron laser within the wavelength range of 5.6–6.7 µm. The incident fluence was fixed at 3.6±0.3 J/cm2. Structural changes of the irradiated gelatin were observed with an optical microscope. At λ=6.05 µm, the wet gelatin was efficiently removed due to vaporization of water, and the absorption coefficient during irradiation increased slightly by 30–40% of magnitude from that before irradiation. Thus, we showed the possibility that 6.05-µm-light can predictably remove soft tissue without unexpected effects. A laser system with λ=6.05 µm is expected to be a novel cutaneous laser.

Gelatin hydrogels cross-linked by γ-ray irradiation: materials for absorption and release of dye

Gelatin hydrogels cross-linked by γ-ray irradiation using 60Co as γ-ray source were prepared. As a model of controlled release of low-molecular-weight compounds, absorption and release of methylene blue, a water-soluble cationic dye, was investigated. Irradiated gelatin hydrogels did not redissolve at temperatures over 40°C, while unirradiated gels were thermoplastic and reversibly changed the stage between gel and sol. Measurement of both the wet weight after swelling in distilled water and dry weight after freeze-drying showed that the higher-dose irradiation gave stiffer and more compact gels with the lower specific water content, irrespective of the absorbed dose rate. The time-course of absorption and release of methylene blue in aqueous solution was measured. Since absorption of dye into gelatin gels was much affected by liquid phase pH, amount of absorption was higher in pH above an IEP of gelatins. Moreover, the absorption and release of methylene blue with Type-B gelatin were higher than with Type-A gelatin, respectively. Therefore, absorption and release of the dye depend on the electrostatic interaction between the dye molecule and gelatin.

Reagent-free crosslinking of aqueous gelatin: manufacture and characteristics of gelatin gels irradiated with gamma-ray and electron beam

In order to obtain a gelatin hydrogel crosslinked by a reagent-free method, gamma-ray and electron beam radiation was applied to porcine, bovine and fish gelatin gels and the products were characterized by measuring the gel fraction, the swelling ratio and the enzymatic degradability. On increasing the radiation dose, the gel fraction increased and both the swelling ratio and the enzymatic degradability decreased. The transition temperature from gel to sol of the hydrogel containing more than 5% mammal gelatins increased up to more than 90°C when gamma-ray or electron beam were irradiated by more than 10 kGy. The results show that the degree of crosslinking of irradiated gelatin hydrogels increases with increasing irradiation dose and with decreasing concentration. It is suggested that the radiation crosslinking occurs around the physical crosslinking point or multiple helix structure of gelatin gel.

Ultra-violet Absorption of Thermally Irradiated Gelatin

AbstractThe effect of thermally irradiated gelatin at various pH's on the ultra-violet absorption at 257nm, the molecular weight and the amount of thermally coagulated material has been studied.Decrease in pH of thermal irradiation leads to molecular weight decreases and ultra-violet absorption increases. The ultra-violet absorption correlates with the molecular weight of the thermally irradiated gelatin. At pH 3-4, however, irradiation leads to a very high ultra-violet absorption which is outside the regression line. The level of thermally coagulated material also increased in this pH range. It would seem that the ultra-violet absorption increase at pH 3-4 is related to the thermal coagulation reaction.

Hardening Reactivity of Ultrasonic Irradiated Gelatin

Hardening Reactivity of Ultrasonic Irradiated Gelatin

Influence of Gamma Radiation on the Gel Rigidity Index and Binding Capability of Gelatin

AbstractChanges in the rigidity indices of gelatin gel before and after gamma irradiation were characterized by dynamic mechanical testing, and the significance of these changes on the strength of granules was evaluated. Results illustrate the difficulty of obtaining reproducible values for gels containing <20% gelatin. However, rigidity indices for gels with a gelatin content of 20% and higher are consistent and may provide a useful controlling factor for preparation of gelatins of more precise specifications. The data indicate that rigidity degradation kinetics of several concentrations of gelatin gel at different radiation doses are complex, showing both increasing and decreasing rates. These findings strongly suggest that doses of <2.0 Mrad of gamma radiation should be used in order to obtain gelatins of acceptable quality for pharmaceutical applications. The crushing strength of granules of lactose powder granulated with irradiated gelatin reveals that the binding capability of such gelatin is significantly reduced. The results obtained for various size fractions and granule hardnesses containing different binder concentrations also suggest that particle size influences the granule strength to a lesser extent than does binder concentration and its consistency.

Comparison of Gamma-Radiation Effects on Solid ATP-Creatine Phosphotransferase and Gelatin

Recent studies (1-4) have shown that differences in radiosensitivity of various amino acid residues within proteins irradiated by y-rays in the dry state are small and that there is no selective breakage of sulfur-sulfur bonds or other covalent structures. In irradiated gelatin and in other fibrous proteins (and also in polyamino acids) the main polypeptide chain is broken, but such degradative action is not apparent with globular proteins. This investigation was undertaken to further substantiate the differences in the properties of these two types of proteins after exposure to y-rays in the dry state.