Pure Gelatin Films Research Articles

Enhancing the properties of gelatin–chitosan bionanocomposite films by incorporation of silica nanoparticles

AbstractFunctional enhancement of biopolymer was attempted in this work for food packaging application. Incorporation of chitosan (0–9%) and silica (0–10%) nanoparticles (NP's) into gelatin film (Gel) has been tried and their effects on moisture content, tensile strength (TS), elongation at break (%E), wettability, water vapor permeability (WVP), and antimicrobial activities were studied. Morphology of nanoparticles was studied using scanning electron microscopy and transmission electron microscopy. Chitosan NP's showed agglomeration at higher concentration which leads to lower the mechanical as well as barrier properties of the film. However, silica NP's enhanced the properties of bionanocomposite film. TS was increased from 6.05 MPa of pure gelatin film to a maximum value of 38.91 MPa at CS NP's of 5.8% and Si NP's of 7%; however, %E decreased with addition of nanoparticles resulting in brittleness of film. WVP for pure gelatin film was 25.21 g mm/kPa m2 day, which reduced to 3.30 g mm/kPa m2 day after incorporation of 10% Si NP's. Antimicrobial activity was observed against E. coli and S. aureus. Incorporation of CS NP's improved the antimicrobial activity of gelatin film. Si NP's showed improvement in mechanical and barrier properties of Gel–CS films, however, had no effect on antimicrobial activities.Practical ApplicationResearchers community are more concerned of natural biopolymers to reduce the use of synthetic polymers, especially in food packaging. Gelatin is one of the natural biopolymer and have potential to be used as food packaging material. Problem with gelatin and many other biopolymer based film is their poor mechanical and barrier properties. Present study was framed to overcome these problems by incorporating silica and chitosan nanoparticles in gelatin film. The results observed would be useful to develop a biopolymer based nanocomposite film with improved mechanical, barrier and antimicrobial properties, which can be used for active food packaging.

A gelatin/PLA-b-PEG film of excellent gas barrier and mechanical properties

A polylactic acid-polyethylene glycol block copolymer (PLA-b-PEG) was used as an additive to prepare gelatin/PLA-b-PEG blend films for the first time. The PEG molecule block enhanced the compatibility of the PLA molecule block with gelatin, which greatly improved the excellent mechanical and gas barrier properties of the gelatin film. The film contained 5 wt% PLA-b-PEG possessed the highest tensile strength and the highest elastic modulus. When the PLA-b-PEG content further increased to 20 wt%, the tensile strength, elastic modulus and elongation at the break of the blend film were all higher than pure gelatin film, suggesting that the gelatin/PLA-b-PEG blend film was pliable and tough. The blend film possessed not only excellent oxygen barrier property, but also a much-improved water barrier property. The degradation rate of the blend film was elongated controllably by regulating the content of the PLA-b-PEG copolymer. The blend film showed great potential in the application of food packaging.

Impact of melting point of palm oil on mechanical and water barrier properties of gelatin-palm oil emulsion film

Abstract In order to explore the effects of oil's melting points on film performance, a gelatin emulsion film with different degrees (8°, 18°, 24°, 33° and 44°, referring to different melting points) of commercial palm oils were fabricated and its properties were investigated. A variety of size distribution (d4,3 and d3,2) of oil droplets in film-forming emulsion was observed, with 24° oil being the smallest and most regular. As expected, the addition of palm oil obviously decreased film strength but increased elongation, depending upon oil degree. Among them, more importantly, strength of the film containing 24° palm oil was close to that of the pure gelatin film, coexisting with a satisfied elongation value. Furthermore, reducing water vapor permeability was observed in all emulsion films, wherein film containing 24° oil was lowest. Increasing degrees of palm oil led to an increase in film's opacity and a variation of film color, as well as thermal stability. The aforementioned different effects were consistent with microstructure of the emulsion films, where the film with 24° oil droplets was smoother and compact. In conclusion, the melting point of palm oil had a remarkable influence on properties of the resulting emulsion film, mainly being attributed to the differences in size and related state of oil droplets in emulsion during film processing.

Antioxidant, Antibacterial, Water Binding Capacity and Mechanical Behavior of Gelatin-Ferula Oil Film as a Wound Dressing Material

Background: Development of biodegradable and biocompatible films based on protein polymer with strong antioxidant and antibacterial activities has gradually obtained extensive concern in the world. In this study, the improvement of gelatin film properties incorporated with Ferula assa-foetida essential oil (FAO) as a potential antioxidant/antibacterial wound dressing film was investigated. Materials and Methods: Gelatin films were prepared from gelatin solutions (10% w/v) containing different concentration of FAO. The effect of FAO addition on water solubility, water swelling, water vapor permeability, mechanical behavior, light barrier properties as well as antioxidant and antibacterial activities of the films were examined. Results: Water solubility, water swelling and water vapor permeability for pure gelatin films were 29 ± 1.6%, 396 ± 8%, 0.23 ± 0.018 g.mm/m2.h, respectively. Incorporation of FAO into gelatin films caused a significant decrease in swelling and increase in solubility and water vapor permeability. Tensile strength, elastic modulus and elongation at break for pure gelatin films were 4.2 ± 0.4 MPa, 5.8 ± 4.2 MPa, 128 ± 8 %, respectively. Incorporation of FAO into gelatin films caused a significant decrease in tensile strength and elastic modulus and increase in elongation at break of the films. Gelatin film showed UV-visible light absorbance ranging from 280 to 480 nm with maximum absorbance at 420 nm. Gelatin/FAO films also exhibited excellent antioxidant ad antimicrobial activities. Conclusions: Our results suggested that gelatin/FAO films could be used as active films due to their excellent antioxidant and antimicrobial features for different biomedical applications including wound-dressing materials.[GMJ.2015;4(2):103-14]

Development of a new family of food packaging bioplastics from cross‐linked gelatin based films

AbstractThe purpose of this work was to develop green bioplastic preparation process from gelatin by using solvent‐free approach with efficient use of resources. Film plasticizing was achieved by adding polyethylene glycol (Mw = 200 g.mol−1). Different cross linking agents – glutaraldehyde (GTA), N‐hydroxysuccinimide (NHS), Bis(succinimidyl)nona(ethylene glycol) (BS(PEG)9) and ferulic acid (FA) were tested to obtain water resistant films suitable for gas permeability characterization. Functional properties (mechanical and gas transfer properties) of gelatin‐based films were determined. Gelatin films cross‐linked with FA presented very good gas barrier properties (48 and 175 cm3.µm/m2.day.kPa respectively for O2 and CO2), compared to synthetic polymers, equivalent to polar polymer like nylon 6 or polyethylene terephthalate and better than non‐polar polymers like high density or low density polyethylene. Swelling ratio measurements in water displayed gelatin/FA films resisted to water without breaking during 4 h compared to 1.5 h for pure gelatin films. Films could support saturated water vapour environment at 20 °C during 15 days without breaking. Gelatin/PEG200 films presented very good permselectivity towards CO2 and O2 (14.5). This value was reduced to 8 when cross‐linked with FA, and to 4 after PEG200 addition, presenting still interesting level. All these results confirmed that gelatin is a promising biobased polymer to prepare food packaging films.

Development and Characterization of Biodegradable Composite Films Based on Gelatin Derived from Beef, Pork and Fish Sources.

The objectives of this study were to develop composite films using various gelatin sources with corn oil (CO) incorporation (55.18%) and to investigate the mechanical and physical properties of these films as potential packaging films. There were increases (p < 0.05) in the tensile strength (TS) and puncture strength (PS) of films when the concentration of gelatin increased. The mechanical properties of these films were also improved when compared with films produced without CO. Conversely, the water barrier properties of composite films decreased (p < 0.05) when the concentration of gelatin in composite films increased. Comparing with pure gelatin films, water and oxygen barrier properties of gelatin films decreased when manufactured with the inclusion of CO.

Preparation and characterization of porous scaffold composite films by blending chitosan and gelatin solutions for skin tissue engineering

AbstractBiodegradable polymers have significant potential in biotechnology and bioengineering. However, for some applications, they are limited by their inferior mechanical properties and unsatisfactory compatibility with cells and tissues. In the present investigation blends of chitosan and gelatin with various compositions were produced as candidate materials for biomedical applications. Fourier transform infrared spectral analysis showed good compatibility between these two biodegradable polymers. The composite films showed improved tensile properties, highly porous structure, antimicrobial activities, low water dissolution, low water uptake and high buffer uptake compared to pure chitosan or gelatin films. These enhanced properties could be explained by the introduction of free OH, NH2 and NHOCOCH3 groups of the amorphous chitosan in the blends and a network structure through electrostatic interactions between the ammonium ions (NH3+) of the chitosan and the carboxylate ions (COO−) of the gelatin. Scanning electron microscopy images of the blend composite films showed homogeneous and smooth surfaces which indicate good miscibility between gelatin and chitosan. The leafy morphologies of the scaffolds indicate a large and homogeneous porous structure, which would cause increased ion diffusion into the gel that could lead to an increase in stability in aqueous solution, buffer and temperature compared to the gelatin/chitosan system. In vivo testing was done in a Wistar rat (Rattus norvegicus) model and the healing efficiencies of the scaffolds containing various compositions of chitosan were measured. The healing efficiencies in Wistar rat of composites with gelatin to chitosan ratios of 10:3 and 10:4 were compared with that of a commercially available scaffold (Eco‐plast). It was observed that, after 5 days of application, the scaffold with a gelatin to chitosan ratio of 10:3 showed 100% healing in the Wistar rat; however, the commercial Eco‐plast showed only a little above 40% healing of the dissected rat wound. Copyright © 2012 Society of Chemical Industry

Efficient transfer of human adipose‐derived stem cells by chitosan/gelatin blend films

Adipose-derived stem cells (ASCs) are a potential source of abundant mesenchymal stem cells and represent a promising cell-based therapy for tissue damage or degeneration conditions. Previous investigations have demonstrated enhanced therapeutic effects of ASCs in a three-dimensional spheroid culture formulation. In this study, we hypothesize that a composite membrane made of chitosan/gelatin (C/G) is beneficial to facilitate transfer of human ASCs in spheroids. Increasing chitosan content within the blends enhanced the mechanical properties of the sample, including tensile strength and elongation-at-break ratio. Although ASC spheroids developed shortly after seeding on pure chitosan films, increasing gelatin proportion in the C/G blends promoted cell adhesion onto the membranes. We also found that ASCs did not proliferate on chitosan films, but C/G blends of different ratios supported ASC proliferation in the first 4 days of culture. However, ASCs on all C/G blends started to detach from the films to form spheroids after day 4, while ASCs on pure gelatin films remained attached and continued to grow. Gradual gelatin release from the C/G blend films, leading to enriched chitosan content in the blends, probably encouraged ASC detachment and spheroid formation. We placed porous collagen matrix on ASC-seeded C/G blends to simulate the application of ASC-seeded C/G films onto injured tissue and found that a C/G film composed of 75% chitosan could facilitate significantly more cell transfer into the overlying collagen sponge. Therefore, a blend film containing 75% chitosan and 25% gelatin showed promising results to serve as a biomaterial for human ASC-based cell therapy.

Studies on the Thermo-Mechanical Properties of Gelatin Based Films Using 2-Hydroxyethyl Methacrylate by Gamma Radiation

Gelatin films were prepared by casting. Tensile strength (TS) and elongation at break (Eb) of the gelatin films were found to be 46 MPa and 3.5%, respectively. Effect of gamma radiation (Co-60) on the thermo-mechanical properties of the gelatin films was studied. 2-hydroxyethyl methacrylate (HEMA) was added to the gelatin during casting varying (10% - 30% by weight) and found to increase the TS significantly. Then the films were irradiated and found further increase of TS. Thermo-mechanical properties of HEMA blended gelatin films were compared with those of the pure gelatin films. The coefficient of thermal expansion of the gelatin/HEMA films were also measured using thermo mechanical analyzer and found opposite trend with comparison of glass point.

Study on the Blend Film Prepared by Chitosan and Gelatin

The viscosities of blend solution mixed with various concentration of chitosan and gelatin were investigated and the properties of the blend films prepared by gelatin and chitosan were studied by FT–IR, DSC and SEM in this paper. The results indicated that the viscosity of blend systems increased with the concentration increasing of chitosan, and that of mixed solution decreased with the concentration increasing of gelatin; there existed strong interactions between chitosan and gelatin molecular chains through hydrogen bond formation and chemical reaction; the surface of blend film had a relatively uniform and compact surface and the thermal stable of blend film was higher than pure gelatin film.

Photocuring of Gelatin Films with TMPTMA: Effect on Aging Properties

Gelatin films were prepared from granular gelatin by casting. Gelatin films were modified by photocuring with a trifunftional monomer Trimethylolpropane trimethacrylate (TMPTMA). Optimum condition for photocuring were established. Water aging of untreated and modified gelatin films was studied. Thermal aging of untreated and TMPTMA treated films were determined at different temperatures (50°C, 70°C and 100°C) for 60 min. pH aging of gelatin films were investigated in different pH solutions (3.2, 4.1, 4.8, 6.9, 9.2, 12.2) for 1min. Water aging, thermal aging and pH aging showed that the TMPTMA grafted gelatin films experienced less deterioration of mechanical properties than pure gelatin films.

Preparation and Characterization of Gamma Radiation Cured Gelatin-PVA Bio-Blend

Gelatin-PVA blend films of different compositions (0%, 5%, 10%, 15% of PVA) were prepared by casting. The tensile strength (TS) and elongation at break (Eb) of the films were studied. The TS and Eb of pure gelatin films were found to be 32 MPa and 3.3% respectively. The films were irradiated under different gamma radiation dose (50 Krad, 100 Krad, 150 Krad, 250 Krad, 500 Krad). 5% PVA containing gelatin films irradiated under 100 Krad gamma radiation showed highest TS of 42 MPa and highest Eb of 4.2%. Thermal property of the films was studied by Thermomechanical analysis (TMA) and Thermogravimetric Analysis (TGA). The grafting of PVA onto gelatin is studied by IR. In order to study surface morphology SEM study was undertaken.

Effect of the addition of pumpkin oil cake to gelatin to produce biodegradable composite films

SummaryThis study was conducted to evaluate the possibility of pumpkin oil cake (PuOC) addition to gelatin in attempt to form biodegradable composite films. Different amounts of PuOC (40–95%) were added to gelatin and films with improved characteristics were made. The best tensile strength (TS) had the film made of 60% gelatin and 40% PuOC, with all used concentration of glycerol, compared to pure gelatin film, made in this work. Elongation to break (EB), increased with increase of PuOC % in films, and when 0.15 and 0.2 g glycerol g−1 protein were used, was two to three times higher then EB of 100% gelatin film, made under the same conditions. Swelling properties, as well as solubility, colour and antioxidant activity were investigated and results showed that film, with similar or improved properties could be produced, when PuOC was added to gelatin.

Gelatin/Poly(ethylene oxide) Blend Films with Compositional Gradient: Fabrication and Characterization

AbstractIn this study, novel protein/biodegradable polymer blend biomaterials‐gelatin/poly(ethylene oxide) blend films with compositional gradients were successfully fabricated by a dissolution/diffusion method. Two kinds of compositional gradient films, which were different in gradient structure, were prepared. The compositional gradient structure in the films was characterized by polarized optic microscopy, ATR‐FTIR, and trans‐FT‐IR mapping measurement. In addition, the mechanical properties of the gradient films were characterized with reference to their gradient structure. It is found that the compositional gradient films have better mechanical properties than the pure gelatin film. These protein/biodegradable polymer compositional gradient films have a potential for many biomedical applications.magnified image

Modulation of In Vitro Attachment, Proliferation and Osteogenic Differentiation of Rat Bone-Marrow-Derived Stem Cells Using Different Molecular Mass Chitosans and Their Blends with Gelatin

We systematically investigated the behaviors of rat bone-marrow-derived stem cells (MSCs) on films prepared from high-molecular-mass chitosan (CH), low-molecular-mass chitooligosaccharide (COS) and their blends with gelatin (G) at various weight blending ratios. On the first day after seeding, the spreading areas of MSCs attached on the blended G/CH and G/COS films were larger than those attached on pure gelatin and COS films. Round-shaped MSCs on pure CH film were observed. The number of proliferated MSCs was also dominant in the case of blended films, at some certain blending ratios which correlated to suitably positive charge of the blended films obtained from zeta potential measurement. Among pure materials, attachment and proliferation of MSCs on COS film were comparable to those on gelatin film while CH film was toxic. The difference in toxicity of CH and COS was also confirmed by Annexin V-FITC/PI apoptosis test. After a 7-day culture under osteogenic induction, the blended films were also found to be more preferable materials for in vitro osteogenic differentiation of MSCs, as confirmed by alkaline phosphatase (ALP) activities, calcium contents and Von Kossa staining. It was proved from this study that attachment, proliferation and osteogenic differentiation of MSCs strongly depended on molecular mass of CHs and the ratio of their blends with gelatin.

Structural and functional properties of soy protein isolate and cod gelatin blend films

The structure-function relationship of composite films obtained from soybean-protein isolate (SPI) and cod gelatin was studied. Films with different ratios of SPI:gelatin (0, 25, 50, 75, 100% [w/w]) and plasticized by a mixture of glycerol and sorbitol were prepared by casting. Regardless of the soybean-protein concentration, the thickness and water-vapor permeability of the composite films diminished significantly as compared to pure-gelatin films. The formulation containing 25% SPI: 75% cod-skin gelatin had the maximum force at the breaking point, which was 1.8-fold and 2.8-fold greater than those of 100% gelatin and 100% SPI films, respectively. Moreover, this formulation offered high percent-deformation values lower than those of gelatin but higher than all other films containing SPI-, and the same relatively low water-vapor permeability as the 100% SPI film. While all the films exhibited high water solubility, a slight reduction in film solubility and soluble protein was observed with increasing SPI concentration. Differential-scanning calorimetry analyses revealed that gelatin was completely denatured in all films, while soy proteins largely maintained their native conformation. Analysis by fourier-transform–infrared spectroscopy revealed that the presence of 25% SPI produced gelatin conformational changes, self-aggregation of gelatin chains, and intermolecular associations via CO bonds between gelatin and SPI proteins. All films were translucent in appearance, but the yellowish color increased with increasing proportions of the soybean proteins.

A LB film morphological study with reference to biopolymer–surfactant interaction taking gelatin–CTAB system as a model

The interaction of gelatin with cetyltrimethylammonium bromide (CTAB) studied at pH 9 and an ionic strength of 0.005, produces an interfacial surface active gelatin-CTAB (monomer) complex (GS(n)(I)), a surface inactive gelatin-CTAB (micelle) complex in bulk (GS(m)(B)), followed by coacervation, and its solubilization in micellar solution of CTAB. We have herein attempted to probe the interfacial morphological changes of gelatin and its CTAB complexes, and not the bulk properties like coacervation and/or micellar solubilization. The morphologies of pure gelatin and CTAB films and that of gelatin-CTAB interacted complex at the interface have been investigated using LB, SEM, AFM and ellipsometric techniques. The stability of the gelatin monolayer at varied concentrations with and without CTAB has been examined. The SEM images of stabilized films of gelatin and gelatin-CTAB complex have witnessed compact smooth as well as rough surfaces with formation of distinct domains. Drastic morphological change in the film before the critical aggregational concentration of CTAB (T(2)) has been in line with an initial abrupt decrease in surface tension. This has been corroborated by AFM measurements, which along with morphology demonstration has provided information on the diameter of the ensembles formed and roughness of the LB films constituted of pure components and their complexes. Thickness of the film was at its maximum in the domain region, as corroborated by ellipsometric technique. Such an elaborate interfacial monolayer and film morphology study of biopolymer-amphiphile system has been rarely documented in literature.

Swelling and electroresponsive characteristics of gelatin immobilized onto multi-walled carbon nanotubes

We prepared multi-walled carbon nanotube (MWNT)/gelatin composites by dispersion of MWNT through ultrasonication in an aqueous medium with anionic surfactant sodium dodecyl sulfate (SDS). The swelling behavior and the bending mechanism of the composite and pure gelatin films were studied in order to clarify the potential use of MWNT in the gelatin actuator. The response of the composite and pure hydrogel to the applied electrical field in the NaCl aqueous solution was investigated. Both the composite and pure hydrogel showed a two-stage bending phenomenon, an early bending towards the anode and a later bending towards the cathode. We investigated the mechanism of this bending phenomenon based on osmotic pressure difference at the inter-phase between the hydrogel film and salt solution. The swelling behavior of the composite was studied by immersion of the vacuum-dried samples into a 0.1 M NaCl aqueous solution at room temperature. The incorporation of MWNT gradually decreased the swelling of the hydrogel and exerted no effect on the swelling mechanism, which followed the second order kinetic. Both the bound and unbound water contents (measured from DSC) decreased with the addition of MWNT. This phenomenon might be due to the hydrophobic effect of the MWNT and increase in crosslinking density between the MWNTs and gelatin by increasing the MWNT concentration.

Absorption of Water by Thin, Ionic Films of Gelatin

This paper discusses absorption of water by thin, dry films of gelatin. Experiments using a wet-stamping technique were performed to characterize water uptake in terms of (i) equilibrium profiles of the water density inside the gel and (ii) the kinetics of water absorption. It was found that, in contrast to pure gelatin films, which absorb water approximately uniformly, films of gelatin doped with ionic additives have exponentially decaying equilibrium water profiles. The process of water absorption by both doped and undoped gels was described by a theoretical model based on the minimization of grand potential functional. The results of this model are in agreement with the experiment.

Characterization of gelatin-surfactant interaction by thickness measurements of foam films

The influence of ionic surfactants (sodium-dodecylsulfate and cetyltrimethylammonium-bromide) on the thickness of gelatin foam films was investigated. The thickness of pure gelatin films was found to be 80 to < 100 nm. Maximum thicknesses are obtained within the range of the isoelectrical point. Foam films stabilized by gelatin-surfactant complexes are found to form common black films with a thickness of 8 to 12 nm. When the surfactant concentration exceeds the binding capacity of the gelatin the common black films turn into Newton-black films with a thickness comparable to that of a pure surfactant solution.