Gelatin Concentration Research Articles

Bioprinted keratinocyte and stem cell laden constructs for skin tissue engineering

Treating large-scale skin wounds continues to be a significant therapeutic challenge. Oftentimes, insufficient autologous material is available to achieve full coverage. Since biofabrication offers the chance of reproducible and precise large-scale production, the aim was to develop a customized 3D bioprinted skin construct containing immortalized HaCaT keratinocytes and ADSC to test the principal feasibility of this approach. Keratinocytes in different hydrogels containing varying concentrations of alginate, fibrin, collagen, gelatin, gelatin methacryloyl (GelMA) and hyaluronic acid as well as on a prefabricated collagen-elastin-matrix were cultured for a period of seven days. The metabolic activity of cultured keratinocytes was then evaluated during the co-cultivation of HaCaT and ADSC in a transwell model. The metabolic activity in all groups increased over the test period. The hydrogels containing alginate/hyaluronic acid/gelatin (Alg/HA/Gel) and GelMA demonstrated a good printability and the highest diffusion rates. There was no significant difference in pore size when comparing all hydrogels with each other. On the basis of the performed printability and diffusion assays as well as on the SEM analysis and rheological measurements Alg/HA/Gel and GelMA were chosen as hydrogels for the bioprinted 3D model. Fibrin hydrogel was integrated into the biofabricated constructs due to its excellent metabolic activity in the transwell model. As a second step, hydrogel stability, cell survival and metabolic activity in bioprinted 3D models containing keratinocytes and ADSC were evaluated over a period of 14 days. On day 14 the metabolic activity as well as the live cell count within the bioprinted constructs of the cocultured groups was significantly higher compared with day 1. The biofabricated constructs made of GelMA showed a higher cell viability compared with those made of Alg/HA/Gel. Additionally, to evaluate the cell migration out of the constructs, the metabolic activity and viability of the cells on the well bottom, was examined. After 14 days, an average of 50% of the well bottom was covered by HaCaT, which were initially printed in coculture into the constructs. These findings indicate that constructs made of GelMA containing keratinocytes and ADSC may offer a promising therapeutic option in the treatment of large chronic wounds.

Complex coacervation of low methoxy pectin with three types of gelatins for the encapsulation of fish oil

Herein, the complex coacervation of low methoxy pectin (LMP) with three types of gelatins was explored to encapsulate fish oil. The fish oil@gelatin-LMP complex coacervates with good precipitation separation could be obtained at low gelatin concentrations (Fish gelatin, FG: 10–80 mg/mL; porcine skin gelatin, PSG: 10–40 mg/mL; bovine skin gelatin, BSG: 10–80 mg/mL), high gelatin: fish oil mass ratios (4:1–1:1), appropriate gelatin: LMP mass ratios (3:1–12:1 for FG and PSG, 6:1 for BSG), and appropriate pH (FG: 4.90–5.50; PSG: 4.80–5.40; BSG: 4.10–4.50). FG induced similar loading ability, lower encapsulation ability, and comparable peroxide values to the mammalian gelatins. FG induced higher or similar free fatty acid released percentages to mammalian gelatins in the in vitro gastrointestinal model at low gelatin concentrations (10–40 mg/mL). These results provided useful information to understand the protein-polysaccharide complex coacervation to encapsulate oil-based bioactive substances.

Tunable gelatin methacrylate polyethylene glycol diacrylate hydrogels for cell mechanosensing applications

Three-dimensional (3D) tissue-engineered scaffolds mimic the physiological environment of cells by providing essential structural support, biochemical cues, and the mechanical strength needed for cell adhesion, proliferation, migration, and differentiation. Hydrogels like polyethylene glycol diacrylate (PEGDA) are commonly used biomaterials for cell culture due to their affordability, tunable stiffness, and ability to efficiently transport nutrients and gases. However, PEGDA lacks cell adhesion sites essential for cell proliferation and migration and has limited degradability. Methacrylated gelatin (GelMA) produced from denatured bovine collagen, crosslinks under ultraviolet light (UV) resulting in a degradable hydrogel with cell adhesion sites. Here, we synthesized GelMA with variable degree of methacrylation and crosslinked it with PEGDA to produce cell scaffolds with independently tunable mechanical and biochemical properties by varying the ratios of the two polymers. We determined polymer ratios that resulted in scaffolds with different mechanical properties but the same gelatin concentrations (providing cell adhesion and degradation sites) as well as different gelatin concentrations but the same mechanical properties. With the developed scaffold library, we further used a design of experiments approach to probe the parameter space and perform detailed analysis on chemical composition-scaffold properties as well as scaffold properties-cell behavior correlations. Our findings showed that hydrogel properties such as modulus, swelling, pore size, and permeability, strongly depended on total polymer concentration and not on the GelMA fraction. GelMA significantly influenced cell spreading, while addition of any amount of PEGDA delayed cell spreading significantly. We suggest that such analysis will broaden the utility of the GelMA/PEGDA hydrogels, presenting a versatile platform for mechanosensing research in 3D environments.

Evaluation of Sensory Attributes of Soft Candy Using Taro Leaf Extract as Influenced by Variations of Gelatin and Glucose Syrup

Although taro is widely grown in Indonesia, it is one of the underutilized crops which is a good source of nutrition. one part of taro that is rarely utilized is the leaves. The objective of this research is to determine the effect of glucose syrup and gelatin concentrations on the organoleptic properties (preference for color, taste, and texture) of soft candy made from taro leaf extract. The method used in this research is experimental which is arranged in a Completely Randomized Factorial Design (CRD) with two factors, which are The concentrations of are (25%, 35%, 45%) and the concentrations of gelatin are (20%, 25%, 30%). Each treatment being repeated three times. The obtained data were analyzed using ANOVA (analysis of variance), and Duncan’s test was conducted if significant differences were obtained. The results shows that soft candy with 35% glucose syrup and 25% gelatin had the highest preference for color. The formulation with 35% glucose syrup and 30% gelatin was most preferred for aroma. The formulation with 45% glucose syrup and 30% gelatin received the highest scores for texture (3.90±0.308) and flavor (3.95±0.63). This research demonstrates that optimizing glucose syrup and gelatin concentrations in soft candies made from underutilized taro leaf extract can significantly enhance specific sensory attributes like texture and flavor. This study can contribute in providing valuable insights for future product development and highlighting the potential of taro leaves as a valuable food ingredient.

Potato flour‐based film: Effect of gelatine on the rheological, thermal, mechanical and barrier properties

SummaryPotato flour/gelatine films in different ratios (6:0, 5:1, 4:1, 3:1, 2:1 and 1:1) were prepared and their properties were examined in this study. Potato flour film‐forming dispersion without gelatine showed the highest particle size and apparent viscosity. As the gelatine concentration increased, the composite films became smoother and more transparent. Gelatine incorporated with potato flour films reduced the retrogradation enthalpy and glass transition temperature, leading to the low tensile strength and high elongation at break. Although water content and water solubility index increased with the higher gelatine concentration, water vapour permeability of composite films decreased from 14.59 × 10−13 gm−1s−1Pa−1 to 5.83 × 10−13 gm−1s−1Pa−1. In addition, it was noted that water contact angle increased from 24.50° to 102.33° as gelatine concentration increased from 0% (6:0) to 50% (1:1). According to these findings, potato flour film with the presence of gelatine showed the better moisture barrier properties.

Improving the stability of spray-dried probiotic acerola juice: A study on hydrocolloids' efficacy and process variables

This study explores the optimization of spray drying conditions for fermented acerola juice powder, focusing on nutrient retention and probiotic viability. Acerola, a fruit high in vitamin C and phenolics, was fermented under varying conditions to support the growth of Lactobacillus gasseri. The fermentation of acerola juice was conducted at pH levels of 3.2(in natura), 5.0, and 7.0 to promote optimal bacterial growth. Spray drying was then performed at inlet temperatures of 120°C, 140°C, and 160°C, using varying concentrations of maltodextrin and gelatin as encapsulants. The powders were analyzed for vitamin C, phenolic content, and Lactobacillus gasseri cell concentration. Optimal bacterial growth occurred at pH 7.0. The spray drying process showed that lower temperatures (120°C) favored higher vitamin C (up to 6.2 mg/g) and phenolic retention (up to 59.9 mg/g), while higher temperatures (160°C) enhanced probiotic survival (up to 8.3 × 108 CFU/g). Hydrocolloids like maltodextrin and gelatin were crucial in enhancing nutrient and probiotic stability, showcasing their importance in optimizing spray-dried functional food formulations. Tailoring fermentation and spray drying conditions is crucial in producing functional fruit powders with high nutritional and probiotic value.

Physically Crosslinked Poly(methacrylic acid)/Gelatin Hydrogels with Excellent Fatigue Resistance and Shape Memory Properties.

Hydrogels endure various dynamic stresses, demanding robust mechanical properties. Despite significant advancements, matching hydrogels' strength to biological tissues and plastics is often challenging without applying potentially harmful crosslinkers. Using hydrogen bonds as sacrificial bonds offers a promising strategy to produce tough, versatile hydrogels for biomedical and industrial applications. Poly(methacrylic acid) (PMA)/gelatin hydrogels were synthesized by thermally induced free-radical polymerization and crosslinked only by physical bonds, without adding any chemical crosslinker. The addition of gelatin increased the formation of hydrophobic domains in the structure of the hydrogels, which acted as permanent crosslinking points. The increase in PMA and gelatin contents generally led to a lower equilibrium water content (WC), higher thermal stability and better mechanical properties. The values of tensile strength and toughness reached up to 1.44 ± 0.17 MPa and 4.91 ± 0.51 MJ m-3, respectively, while the compressive modulus and strength reached up to 0.75 ± 0.06 MPa and 24.81 ± 5.85 MPa, respectively, with the WC being higher than 50 wt.%. The obtained values for compressive mechanical properties are comparable with super-strong hydrogels reported in the literature. In addition, hydrogels exhibited excellent fatigue resistance and biocompatibility, as well as great shape memory properties, which make them prominent candidates for a wide range of biomedical applications.

Extraction and physicochemical characterization of native and broiler chicken feet gelatin.

Poultry processing generates a large amount of industrial waste, which is rich in collagen content. This waste can be utilized for the extraction of valuable components such as gelatin, which can be used as an alternative to mammalian gelatin (porcine and bovine). Gelatins were analyzed for their yield, proximate analysis, pH, color, viscosity, bloom strength, and texture profile analysis. The yield of broiler chicken feet gelatin (BCFG) was slightly higher (7.93%) as compared to native chicken feet gelatin (NCFG) (7.06%). The protein content was 85.92% and 82.53% for BCFG and NCFG. Both gelatin had moisture content in the standard range (< 15) as given by Gelatin Manufacturers of Europe (GME). Both gelatins showed higher bloom strength (326 g for NCFG and 203 g for BCFG) at 6.67% gelatin concentration, classified as high bloom. Fourier-transform infrared (FTIR) analysis showed amide I, amide A, amide B at 1636 cm-1, 3302 cm-1, 2945 cm-1 for NCFG and 1738 cm-1, 3292 cm-1, 2920 cm-1 for BCFG. At 6.67% gelatin concentration, hardness and cohesiveness values were also higher than commercial gelatin previously studied. The pH values for NCFG were 5.43 and BCFG was 5.31. Both NCFG and BCFG viscosities (4.43 and 3.85 cP) were in the optimum range of commercial gelatins (2-7 cP). Hence, the present study concluded that both NCFG and BCFG have a huge potential to replace commercial mammalian gelatins (porcine and bovine) in the food industries. However further studies should be done to optimize the extraction process. © 2024 Society of Chemical Industry.

Formation, characterization of gelatine from the scales of Labeo rohita and its comparison with bovine bone gelatine

The study isolated gelatin from Labeo rohita scales and characterized it using Fourier transform infrared spectroscopy (FTIR), X-Ray diffraction (XRD), and scanning electron microscopy (SEM). The resulting gelatine and commercial bovine bone gelatin were found to have crystalline structures, with both being porous and spherical. L. rohita scales yielded 5.45 % of gelatin. The moisture content varied between 11.12 % and 9.02 % for the gelatin, while the ash content varied between 2.17 % and 2.36 %. The protein content was 82.78 % in the fish scales gelatin, while the commercial bovine bone gelatin had 94.27 %. The fat content of gelatin isolated from scales of L. rohita was 1.21 %, whereas fat in commercial bovine bone gelatin was 1.19 %. The fiber contents of gelatin isolated from fish scales was 0.44 % while fiber content of commercial bovine bone gelatin was 0.65 %. The study confirms the high-quality gelatin-bearing characteristics of fish scales, suggesting that it can be produced for various purposes and potentially increase the economic value of fish. The isolated gelatin from fish by-products could also be a valuable resource.

β-galactosidase immobilization on ceramic ultrafiltration membrane for simultaneous lactose hydrolysis and protein separation

Protein and lactose of cheese whey can be separated using ultrafiltration membranes and lactose can be hydrolyzed by β-galactosidase. This study investigated the integration of ultrafiltration and enzymatic hydrolysis for simultaneous protein concentration and lactose hydrolysis. β-galactosidase was immobilized on ceramic membrane via surface activation with gelatin and subsequent enzyme cross-linking with glutaraldehyde. Membrane geometries, buffer types, gelatin and enzyme concentrations were optimized. The optimal results yielded a 63 % enzyme immobilization efficiency and a 93 % lactose hydrolysis rate by using disc membrane, sodium acetate buffer (pH 4.8), sodium phosphate buffer (pH 7.5), 0.1 g/L gelatin concentration, and 5.0 g/L enzyme concentration. The optimized enzymatic membrane was evaluated with synthetic and real whey. In synthetic whey, 85 % lactose hydrolysis and 89 % protein rejection were achieved. While in real whey, 72 % lactose hydrolysis and 83 % protein recovery were obtained. This approach offers a single-step, efficient, and scalable method for whey valorization with potential for industrial applications.

The use of fluid-phase 3D printing to pattern alginate-gelatin hydrogel properties to guide cell growth and behaviour in vitro

Three-dimensional (3D) (bio)printing technology has boosted the advancement of the biomedical field. However, tissue engineering is an evolving field and (bio)printing biomimetic constructions for tissue formation is still a challenge. As a new methodology to facilitate the construction of more complex structures, we suggest the use of the fluid-phase 3D printing to pattern the scaffold’s properties. The methodology consists of an exchangeable fluid-phase printing medium in which the constructions are fabricated and patterned during the printing process. Using the fluid-phase methodology, the biological and mechanical properties can be tailored promoting cell behaviour guidance and compartmentalization. In this study, we first assessed different formulations of alginate/gelatin to create a stable substrate capable to promote massive cell colonization in vitro over time. Overall, formulations with lower gelatin content and 2-(N-morpholino)ethanesulfonic acid (MES) buffer as a solvent showed better stability under cell culture conditions and enhanced U2OS cell growth. Next, the fluid-phase showed better printing fidelity and resolution in comparison to air printing as it diminished the collapsing and the spread of the hydrogel strand. In sequence, the fluid-phase methodology was used to create functionalized alginate-gelatin-arginylglycylaspartic acid peptide (RGD) hydrogels via carbodiimides chemistry. The alginate-gelatin-RGD hydrogels showed an increase of 2.97-fold in cell growth and more spread substrate colonization in comparison to alginate-gelatin hydrogel. Moreover, the fluid-phase methodology was used to add RGD molecules to pre-determined parts of the alginate-gelatin substrate during the printing process promoting U2OS cell compartmentalization. In addition, different substrate stiffnesses were also created via fluid-phase by crosslinking the hydrogel with different concentrations of CaCl2 during the printing process. As a result, the U2OS cells were also compartmentalized on the stiffer parts of the printings. Finally, our results showed that by combining stiffer hydrogel with RGD increasing concentrations we can create a synergetic effect and boost cell metabolism by up to 3.17-fold. This work presents an idea of a new printing process for tailoring multiple parameters in hydrogel substrates by using fluid-phase to generate more faithful replication of the in vivo environment.

Gelatin and Collagen from Sheepskin.

Abattoirs dispose of sheepskins as solid waste due to low price and poor demand for sheepskin leather. In principle, as an alternative to being disposed of in landfill, sheepskins can serve as a source of the protein collagen or the hydrolysis product, gelatin. In this research, sheepskins collected from abattoirs were used as a source of collagen. Three extraction methods were compared: acid extraction, acid with enzymes, and alkali extraction. The extracted material was characterized using scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR), small angle X-ray scattering (SAXS), and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The collagen and gelatin extraction yield ranged from 3.1% to 4.8% with the product purity determined by hydroxyproline, ranging from 7.8% for the alkali process to 59% and 68% for the acid and acid-enzyme processes. SDS PAGE showed that the acid process produced fragments with molecular weights in the range 100 to >250 kDa, while acid-enzyme resulted in smaller fragments, below 30 kDa. The FTIR region of the amide I band at 1800-1550 cm-1, which was used as an indicator of the collagen and gelatin content, showed that the gelatin dominated in the acid extracts, and the alkaline extract contained a large portion of keratin. SAXS was found to be a sensitive method for showing the presence of intact collagen fibrils in materials from all of the extraction methods, albeit at low concentrations. Herein, sheepskin is shown to be a useful source for collagen-gelatin material of varying molecular weights.

A new synthesis method of flexible microcapsules applied for electrophoresis display

This study prepared a new type of electrophoretic display microcapsule with flexibility and strength, namely gum arabic/gelatin/urea-formaldehyde resin microcapsule, based on polysaccharides as the reaction starting point, combined with proteins and resins. The composition, morphology and thermal stability of the microcapsules were tested by Fourier transform infrared spectroscopy, stereo fluorescence microscopy, scanning electron microscopy and thermogravimetric analysis. It was found that the morphology and stability of the new microcapsules prepared by the method are better than those prepared by the traditional complex coacervation method or the in-situ polymerization method. At the same time, it showed that the rotational speed was between 1000 rpm and 1200 rpm, the concentrations of gum arabic and gelatin were 3 wt%, the reaction pH between 3 and 3.5, the reaction duration is between 150 min and 180 min, the ammonium chloride was 20 wt%, and resorcinol was 6 wt%, the reaction between the urea-formaldehyde prepolymer and the electro-neutralizer formed by gelatin and gum arabic was sufficient, the microcapsule wall structure was uniform and consistent, with a dense resin based structure on the outer layer and a flexible blend structure inside.

Development of a bacterial cellulose-gelatin composite as a suitable scaffold for cardiac tissue engineering.

Cardiac tissue engineering is suggested as a promising approach to overcome problems associated with impaired myocardium. This is the first study to investigate the use of BC and gelatin for cardiomyocyte adhesion and growth. Bacterial cellulose (BC) membranes were produced by Komagataeibacter xylinus and coated or mixed with gelatin to make gelatin-coated BC (BCG) or gelatin-mixed BC (mBCG) scaffolds, respectively. BC based-scaffolds were characterized via SEM, FTIR, XRD, and AFM. Neonatal rat-ventricular cardiomyocytes (nr-vCMCs) were cultured on the scaffolds to check the capability of the composites for cardiomyocyte attachment, growth and expansion. The average nanofibrils diameter in all scaffolds was suitable (~ 30-65nm) for nr-vCMCs culture. Pore diameter (≥ 10µm), surface roughness (~ 182nm), elastic modulus (0.075 ± 0.015MPa) in mBCG were in accordance with cardiomyocyte requirements, so that mBCG could better support attachment of nr-vCMCs with high concentration of gelatin, and appropriate surface roughness. Also, it could better support growth and expansion of nr-vCMCs due to submicron scale of nanofibrils and proper elasticity (~ 0.075MPa). The viability of nr-vCMCs on BC and BCG scaffolds was very low even at day 2 of culture (~ ≤ 40%), but, mBCG could promote a metabolic active state of nr-vCMCs until day 7 (~ ≥ 50%). According to our results, mBCG scaffold was the most suitable composite for cardiomyocyte culture, regarding its physicochemical and cell characteristics. It is suggested that improvement in mBCG stability and cell attachment features may provide a convenient scaffold for cardiac tissue engineering.

Multiple factors influencing high-purity indium electrolytic refining

The effects of various contaminants in the electrolytic refinement of indium were investigated using a glow discharge mass spectrometer (GDMS). The effects of several factors such as the indium ion (In3+) concentration, the sodium chloride (NaCl) concentration, the current density, the gelatin concentration, the pH, and the electrode distance, were examined. Significant variations in impurity levels concerning gelatin concentration were observed. Both the gelatin and In3+ concentration were moderately positively correlated with the Pb content. The Sb concentration was associated positively with the NaCl concentration, while the Ti concentration had an adverse correlation with the NaCl concentration. The Bi element content was positively linked to the electrode distance. As the current density increased, Cu, Pb, and Bi impurities initially rose and then eventually declined. Notably, a critical current density of 45 A·m−2 was identified in this behavior.

Effect of gelatin concentration and freezing temperature on porous scaffolds for cultured meat

Cultured meat is an emerging green alternative for livestock and poultry meat, and obtained from cell cultured in laboratories or factories. Three-dimensional (3D) scaffolds are widely used in cultured meat production by simulating extracellular matrix to support cell culture in vitro. Currently, the scaffolds used for the fabrication of cultured meat lack the research on porous structures, which limit cell growth and differentiation and simulation of distinct textural characteristics of traditional meat. Therefore, this study investigated the efficacy of food-grade scaffolds prepared with different gelatin concentrations and freezing temperatures to support cell attachment and growth. The result showed 6% gelatin scaffolds prepared at −80 °C or liquid nitrogen demonstrated suitable porous structures and promoted the proliferation and differentiation of muscle stem cells (MSCs) to improve the expression of genes and proteins (myogenin and myosin) related to myogenic progression. The scaffolds also created 3D-engineered cultured meat tissues that closely mimic the mechanical properties of traditional meat. This study provides the theoretical baseline for developing porous scaffolds for efficient cultured meat production in the meat substitute industry.

Development of multi-cross-linking, rapid curing, and easy cleaning, edible hydrogels for meat preservation

The design and development of a food preservation coating material with rapid curing and stable performance to shorten the coating process time and reduce quality changes caused by temperature fluctuations in cold chain is highly desirable in fresh meat preservation applications. In this study, a series of multi-cross-linked edible hydrogels were designed based on gelatin and k-carrageenan through the self-assembly triple-helix of gelatin and the potassium ion-mediated k-carrageenan double-helix structure. The tannic acid with phenolic hydroxyl groups was employed to enable the dynamic bond cross-linking between two polymers, endowing the composite hydrogel with rapid curing ability at low-temperature and a uniform molecular network structure. The hydrogel with a concentration of gelatin was 16% (GCBG-16) achieved the optimal combination properties, including 73.41% of elongation at break, 71.59 kJ/m2 of toughness, 27.73% of swelling ratio, and 50.73% of DPPH· scavenging rate. The hydrogels could be rapidly washed within 30 min at 40 °C by water, as well as possessing a certain self-healing and anti-freezing capabilities. The hydrogel GCBG-16 had a great capacity for protecting meat with a E value of 50.4 and 17.53 N of shear force even placed in a 37 °C environment, which showed no significant difference (p > 0.05) compared to the initial value. Furthermore, the fresh meats with coating showed delayed central temperature increase speed after leaving from the cold chain and placed in a 37 °C environment. The research results demonstrated that the proposed hydrogel has great potential in preserving fresh meat, which can serve as a matrix material combined with other active additives for extending the shelf life of meat products.

Fabrication and evaluation of gelatin cryogels for curcumin controlled release via transdermal iontophoresis

Transdermal drug delivery system delivers a drug through skin to the desired cells. Its use is limited due to the poor drug diffusion through the outer skin layer. The aim of this work was to fabricate and characterize the gelatin cryogel matrices for the targeted transdermal curcumin delivery via iontophoresis for the breast cancer treatment. The gelatin cryogels were fabricated at various concentrations under the freeze-drying method. FTIR, SEM, STA, and BET were utilized to characterize the gelatin cryogels and curcumin loaded gelatin cryogels. The curcumin release behavior was investigated under the effects of gelatin concentrations, electric fields, pig skin permeation, and pHs. The gelatin cryogel matrices possessed the interconnected pore sizes between 56.61 μm and 129.67 μm, in which the pore size increased with increasing gelatin concentration. The curcumin percentage released from the 1.5%v/v PSG cryogel was 89.7 %, relatively higher than the 0.8%v/v PSG cryogels. Under the effect of electric fields of 3V and 6V, the curcumin release percentages from the 1.5%v/v PSG cryogel were increased to reach 94.7 % and 96.0 %, respectively. For the release-permeation of curcumin through the pig skin, the curcumin release percentages from the 1.5%v/v PSG cryogel under the electric fields of 0V, 3V, and 6V became lower at 38.45 %, 46.33 %, and 72.33 %, respectively, as the pig skin was the obstacle in the curcumin diffusion. Slightly higher release rates and amounts of curcumin from the 1.5%v/v PSG cryogel were observed at the of pH 5.5 relative to the pH of 7.4, and at the electric field of 6V relative to 0V. The effect of applied electric field was shown to shorten the delivery time from the PSG cryogel. The 1.5%v/v PSG cryogel under applied electric field 6V was shown here as a potential biobased matrix to be used in the curcumin transdermal delivery via iontophoresis for cancer treatment.

GELATIN AND VEGF INCORPORATION IN PVA-TYRAMINE HYDROGELS AS A STRATEGY TO ENHANCE VASCULAR INFILTRATION AND TREAT AVASCULAR NECROSIS

INTRODUCTIONStimulation of angiogenesis via the delivery of growth factors (GFs) like vascular endothelial growth factor (VEGF) is a promising strategy for the treatment of avascular necrosis (AVN). Tyraminated poly-vinyl-alcohol hydrogels (PVA-Tyr), which have the ability to covalently incorporate GFs, were proposed as a platform for the controlled delivery of therapeutic levels VEGF to the necrotic areas[1]. Nevertheless, PVA hydrophilicity and bioinertness limits its integration with the host tissues. The aim of this study was to investigated the effectiveness of incorporating gelatin, an FDA-approved, non-immunogeneic biomaterial with biological recognition sites, as a strategy to facilitate blood vessels invasion of PVA-Tyr hydrogels and to restore the vascular supply to necrotic tissues.METHODSProgressively higher gelatin concentrations (0.01–5wt%) were incorporated in the PVA-Tyr network. Hydrogel physico-chemical properties and endothelial cell attachment were evaluated. Afterwards, the capability of the released VEGF and gelatin to promote vascularization was evaluated via chorioallantoic membrane (CAM) assay. VEGF-loaded PVA-Tyr hydrogels with or without gelatin (n=7) were implanted in a subcutaneous mouse model for 3 weeks. Vascularization (CD31+ cells) and cell infiltration (H&amp;E) were evaluated. Finally, AVN was induced in 6 weeks old male piglets as previously described [2]. A transphyseal hole (3mm) was drilled and PVA-Tyr hydrogels with 1% gelatin were delivered in the defects. Piglets were euthanized after 4 weeks and microCT analysis was performed.RESULTSThe incorporation of 1% gelatin significantly enhanced cell attachment without compromising hydrogels physical properties, degradation time, VEGF retention and release. Thus, this gelatin concentration was selected for further analysis. Additionally, the covalent incorporation of VEGF or gelatin to the PVA-Tyr network does not hamper their bioactivity, as both still promoted neo-angiogenesis in a CAM assay. Following subcutaneous implantation, the presence of gelatin did not increase the cellular infiltration in the PVA-Tyr hydrogels. Nevertheless, higher vascular infiltration was observed in the groups where either gelatin or VEGF were included. Additionally, preliminary microCT results indicated that the delivery of PVA-Tyr hydrogels containing 1% gelatin in an AVN model was effective in preventing the necrosis-associated resorption of the bone.DISCUSSION &amp; CONCLUSIONSThese results indicated that the presence of either gelatin or VEGF was sufficient to promote vascular infiltration. Additionally, preliminary results suggested the suitability of the developed hydrogels to treat AVN.

Tilapia head gelatins to stabilize fish oil emulsions and the effect of extraction methods

The preparation and use of gelatins from fish by-products have attracted much attention in the field of food science. Herein, four types of tilapia head gelatins were extracted and characterized: hot water-pretreated gelatin (HWG), acetic acid-pretreated gelatin (AAG), sodium hydroxide-pretreated gelatin (SHG), and pepsin enzyme-pretreated gelatin (PEG). The gel strength values followed the order: PEG (74 ± 1 Bloom) > AAG (66 ± 1) > HWG (59 ± 1) > SHG (34 ± 1). The foaming properties, fish oil emulsion viscosity, emulsion activity, and emulsion stabilization ability followed this order: PEG > HWG ≥ AAG > SHG. The effect mechanisms of extraction methods and gelatin concentrations on the emulsion stability involved the interfacial tension, emulsion viscosity, and fat-binding capacity. This work provided important knowledge for analyzing the relations between the structure and function of gelatin. It also provided a high-value application method of fish wastes.