Blend Gel Research Articles

Establishment of a tumor neovascularization animal model with biomaterials in rabbit corneal pouch

AimsThe present animal model of tumor neovascularization most often used by researchers is zebrafish. For studies on human breast cancer cell neovascularization, a new animal model was established to enable a more convenient study of tumor neovascularization. Main methodsA sodium alginate-gelatin blend gel system was used to design the new animal model. The model was established using rabbit corneal pouch implantation. Then, the animal model was validated by human breast cancer cell lines MCF-7-Kindlin-2 and MCF-7-CMV. Key findingsThe experiment intuitively observed the relationship between tumor and neovascularization, and demonstrated the advantages of this animal model in the study of tumor neovascularization. SignificanceThe use of sodium alginate-gelatin blends to establish tumor neovascularization in a rabbit corneal pouch is a novel and ideal method for the study of neovascularization. It may be a better animal model for expanding the research in this area.

Aloe vera gel influence on the micellization behavior of copolymer Pluronic F127: A potential photosensitizer carrier for topical application

ABSTRACTThis work describes the influence of aloe vera gel on Pluronic F127 triblock copolymer (F127) micellization behavior. Aloe vera gel was obtained from aloe vera mucilage found in leaf pulp. F127 (20% w/w) gel and the aloe vera/F127 blend gel were obtained by using the cold method. Fourier transform infrared spectroscopy and X‐ray diffraction analyses of lyophilized samples did not show any important copolymer interaction between aloe vera gel and F127. However, in aqueous medium, the dynamic light scattering data showed that there was an important reduction in micelle size with increasing temperature of the aloe vera/F127 blend hydrogel. The differential scanning calorimetry results indicate that the aloe vera/F127 blend has a higher micellization temperature, affected by the lower dehydrating effect of the poly(propylene oxide) blocks during the micelle formation in comparison to F127 gel. The texture analyses (hardness and adhesiveness) showed that the addition of aloe vera gel did not change the Pluronic F127 gel texture properties. The photosensitizer zinc phthalocyanine (ZnPC) was incorporated into the aloe vera/F127 blend, and the results suggest that this formulation is suitable as a ZnPC delivery system for photodynamic therapy. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46191.

The gelation properties of tara gum blended with κ-carrageenan or xanthan

The gelation properties and structure characteristics of tara gum blended with κ-carrageenan or xanthan were respectively investigated by texture analysis, dynamic rheology and morphological observation. Results indicated that tara gum, a non-gelling polysaccharide, could form thermo-reversible gels in the case of mixture of κ-carrageenan or xanthan, the melting and gelling points were elevated with increasing mixture concentration. There was a synergistic interaction in the two blend systems, which was directly observed by scanning electron microscope or atomic force microscope. The maximum gel strength occurred when blend ratio and blending temperature of the two blends (tara gum-κ-carrageenan, tara gum-xanthan) were 2:8, 80 °C; 4:6, 60 °C respectively. Besides, appropriate amount of salt ions could significantly enhance the gel strength of tara gum-κ-carrageenan blend gel, which could be weakened by excess salt ions. While salt ions had no obvious enhancing effect in the gelation of tara gum-xanthan blend system. The understanding of gelation properties and gelling mechanism is beneficial for the diversified and value-added application of tara gum in food and chemical industries.

Stretchable Ionic-Liquid-Based Gel Polymer Electrolytes for Lithium-Ion Batteries

Stretchable cross-linked gel polymer electrolytes (C-GPEs) have been fabricated through electron-beam irradiation (EBI) of poly(vinylidene fluoride-co-hexafluoropropylene) [P(VDF-co-HFP)]/triallyl isocyanurate (TAIC) blend films followed by adsorption of the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIm][TFSI]). It was found that polymer films containing 5 wt % cross-linker exhibit an excellent IL uptake value of 3.0 when irradiated at 75 kGy. The prepared C-GPEs have a high ion conductivity of 1.4 mS/cm at room temperature compared with a value of 0.7 mS/cm for P(VDF-co-HFP)/IL (1/3, m/m) blend gel. Morphological measurements indicate interconnected nanoporous structures in the films that can provide effective channels for ion immigration. Moreover, the C-GPEs show a high tensile strength of 10.6 MPa and an excellent elasticity, with almost full strain recovery after 100% stretch. In a LiFePO4/C-GPE/Li half-cell, the C-GPEs exhibit high electrochemical stability. There...

Formulation and In Vitro Release Kinetics of Mucoadhesive Blend Gels Containing Matrine for Buccal Administration.

Enterovirus 71 (EV71) is a pathogenic factor of severe hand, foot, and mouth disease (HFMD). No vaccine or specific treatment is currently available for EV71 infection. Hence, we developed a buccal mucoadhesive gel containing matrine to protect against HFMD. Mucoadhesive gels were prepared by Carbopol 974P and were combined with Carbopol 971P, sodium carboxymethyl cellulose (CMC-Na), or hydroxypropylmethy cellulose (HPMC K100M). The formulations were characterized in terms of tensile testing and continuous flow techniques for mucoadhesion. The rheological studies and in vitro drug release characteristics were also investigated. The results showed that combinations of two polymers significantly improved mucoadhesion, especially Carbopol 974P blended with HPMC. Carbopol 974P to HPMC blend ratios of 1:1 and 2:1 induced better mucoadhesion in the tensile test and continuous flow method, respectively. The most sustained release was obtained at a Carbopol 974P to HPMC ratio of 2.5:1. A predominantly non-Fickian diffusion release mechanism was obtained. The gel containing 2.5% Carbopol 974P combined with 1% HPMC showed good mucoadhesion properties and sustained drug release.

κ-Carrageenan/locust bean gum as hard capsule gelling agents

A novel gelling agent, comprising blended κ-carrageenan (κ-C), a seaweed polysaccharide and locust bean gum (LBG), was used to prepare hard capsules. The distinct synergism between κ-C and LBG were verified by the textural profile analysis (TPA), FTIR and rheological measurement. Afterwards, films and hard capsules were prepared with the optimized LBG/κ-C blend gel. And the mechanical properties and morphology of films and hard capsules were analyzed by tensile testing and SEM, respectively. The results showed that the LBG/κ-C at 1:3 ratio could serve as an excellent gelling agent, which endowed hard capsule with the promoted mechanical properties, homogenous and smooth surface morphology. This work suggests that a novel blended LBG/κ-C gelling agent successfully prepared for hard capsules with improving physicochemical properties.

Presence of NaI in PEO/PVdF-HFP blend based gel polymer electrolytes for fabrication of dye-sensitized solar cells

Poly(vinylidene fluoride-co-hexafluoro propylene) copolymer (PVdF-HFP) and polyethylene oxide (PEO) blend gel polymer electrolytes (GPEs) containing ethylene carbonate (EC) and propylene carbonate (PC) as solvent with different concentrations of sodium iodide (NaI) salt are prepared. Effect of sodium iodide (NaI) on the gel polymer electrolyte system is investigated by using electrochemical impedance spectroscopy (EIS), temperature-dependence ionic conductivity, X-ray diffraction (XRD) and FTIR studies. The highest ionic conductivity value for the gel polymer electrolytes are 6.38mScm−1 in the presence of 100wt% of sodium iodide (NaI) salt with respect to weight of PEO/PVdF-HFP polymer blend. The temperature-dependent ionic conductivity study indicates that the gel polymer electrolyte system follows the Arrhenius model. Dye-sensitized solar cells (DSSCs) are fabricated using gel polymer electrolytes and tested under Sun simulator. The highest energy conversion efficiency value of 5.67% is obtained after the addition of 100wt% of sodium iodide (NaI) salt.

Self-assembly and drying assisted microstructural domain formation in poly(vinyl alcohol) and hyaluronic acid gels

Aqueous solutions of hydrophilic polymers and charged polysaccharides are known to have variety of microstructures. In this work, we show microstructures formed on the surface of poly vinyl alcohol (PVA) and hyaluronic acid (HA) blend gels. At specific hyaluronic acid composition in the blend, when PVA is crosslinked to form gels, both these polymers phase separate. This crosslinking reaction induced phase separation was examined by varying the moisture contents in the hydrogels. We also examine the precursor PVAHA blend solutions to highlight the origins of self-assembled structures. The evolution of microstructure domains leads to the formation of different shapes, such as sphere like particles to rod like assemblies on the surface. Such phase separation can be used to synthesize particles of different shapes and sizes.

Conductivity studies of poly(ethylene oxide)(PEO)/poly(vinyl alcohol) (PVA) blend gel polymer electrolytes for dye-sensitized solar cells

Poly(ethylene oxide)(PEO)–poly(vinyl alcohol) (PVA) blend-based gel polymer electrolytes (GPEs) have been prepared by blending equal weights of PEO and PVA in ethylene carbonate (EC), dimethyl sulfoxide (DMSO), tetrabutylammonium iodide (TBAI), and iodine crystals (I2). The conductivity, diffusion coefficient, number density, and ion mobility of the electrolytes have been calculated from the impedance data obtained from electrochemical impedance spectroscopy (EIS) measurements. The GPE with the composition of 7.02 wt%, PVA, 7.02 wt% PEO, 30.11 wt% ethylene carbonate (EC), 30.11 wt% DMSO, 24.08 wt% TBAI and 1.66 wt% I2 exhibits the highest conductivity of 5.5 mS cm−1 at room temperature. Dye-sensitized solar cells (DSSCs) with configuration fluorine tin oxide (FTO)/titanium dioxide/N3-dye/GPE/platinum/FTO have been fabricated and tested under the white light of intensity 100 mW cm−2. The DSSC containing the highest conducting GPE exhibits the highest power conversion efficiency, η of 5.36 %.

Influence of sugarcane dietary fiber on water states and microstructure of myofibrillar protein gels

The effects of different size particles and contents of sugarcane dietary fiber(SDF) on water state, water holding capacity(WHC), gel strength and microstructure of myofibrillar protein gels was studied. It was found that gel strengths were improved with the increase in SDF particle size and content, and the value of water holding capacity (WHC) reached a maximum with the addition of 80-mesh SDF at 2%. Discrete exponential fitting analysis and multi-exponential function analysis of the T2 relaxation time revealed that three categories of water, each having different mobility states in the gels, had different effects on the blended gel systems. Also, the intrinsic T21 relaxation time of immobile water in gels containing SDF was shorter than that in pure gels. Pronounced differences in myofibrillar gel network structures were observed during heating at 80 °C for 20 min. The fractal dimension which was determined by the box count method and the pore density (diameter < 0.1 μm or < 1 μm) further demonstrated that the homogeneity and compactness of gels increased with higher SDF content. However, the formation of numerous SDF cavities, whose particle size and number was enormously affected by the particle size and ratio of SDF added, is likely to have been responsible for the decrease in WHC and the extension of the intrinsic T21 relaxation times of immobilized water.

Studies on Swelling and Absorption Properties of theγ– Irradiated Polyvinyl Alcohol (PVA)/Kappa-Carrageenan Blend Hydrogels

A series of hydrogels were prepared from an aqueous mixture of Poly vinyl alcohol (PVA) and Kappa-carrageenan (KC) and irradiated the mixture at 25 kGy radiation dose with γ-radiation from 60Co γ source at room temperature (25°C). The effects of KC on the properties, such as gel fraction, swelling ratio (e.g., in distilled water, in NaCl solution with different concentration, buffer solution with different pH), water absorption, water desorption, moisture absorption and uptake of metal ion from aqueous solution of the prepared hydrogels were investigated. Incorporation of KC into the PVA obviously influences the properties of hydrogels. It is found that the gel fraction of the prepared hydrogel decreased but swelling ratio increased with increase in concentration of Kappa-carrageenan. Swelling properties in NaCl decreased with increased concentration of NaCl in aqueous solution. Swelling of the blend gel in buffer increased with the increase in pH. Water absorption properties showed that maximum absorption occurred within 24 hrs and then increasing trend of water absorption was insignificant. Water desorption is very fast upto 48 hrs and then attained a plateau value. The maximum moisture absorption occurred within 48 hrs and then the absorption was insignificant. Kappa-carragenan influences to uptake of metal (Cu+2) by PVA / KC blend hydrogel with time.

Abstract 4535: Graphene/Pectin-NaCl based gel-biosensor for tracing skin cancer and delivery of anticancer drug paclitaxel

Abstract Graphene(GO)/Pectin/NaCl gel-patch was prepared and evaluated for its bio-sensing. Physical and chemical analyses were carried out to focus the properties of new bio-sensing gel. Afterwards paclitaxel was loaded in the graphene based gel and drug delivery was carried out for dermal delivery, using a biomembrane, a fish swim-bladder in vitro. Kinetic studies were evaluated for feasibility as dermal delivery. Getting information from the kinetic parameters, paclitaxel was delivered to the melanoma cell lines from the gel and cell apoptosis was performed by trypan blue staining. FTIR studies were performed to evaluate the IR-signal transmission between the GO/Pectin/NaCl blend gel and Pectin/NaCl gel. And the same signal was evaluated from that of paclitaxel loaded GO/Pectin/NaCl treated melanoma cells and normal endothelial cells. All our data suggests that GO/Pectin/NaCl blend gel might be a future diagnostic as well as curable anticancer carrier for local cancer therapy. Note: This abstract was not presented at the meeting. Citation Format: Sharif M. Shaheen, Daniel Gromadzki, Amor Abdelkader, Stanislav Rangelov. Graphene/Pectin-NaCl based gel-biosensor for tracing skin cancer and delivery of anticancer drug paclitaxel. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4535. doi:10.1158/1538-7445.AM2015-4535

Improvement of ionic conductivity and performance of quasi-solid-state dye sensitized solar cell using PEO/PMMA gel electrolyte

Polymer blend gel electrolytes based on polyethylene oxide (PEO) and poly(methyl methacrylate) (PMMA) as host polymers with various weight ratios, LiI/I2 as redox couple in electrolyte and 4-tert-butyl pyridine as additive were prepared by solution method. The introduction of PMMA in the PEO gel electrolyte reduced the degree of crystallinity of PEO, which was confirmed by differential scanning calorimetry (DSC). Complexation and ionic conductivity as a function of temperature were investigated with Fourier transform infrared and ionic conductometry, respectively. A good correlation was found between the degree of crystallinity and ionic conductivity. The reduction in crystallinity, governed by blending ratio, led to improvement of ionic conductivity. The best ionic conductivity was attained in PEO/PMMA blend with 10/90w/w composition. The performance of a quasi-solid-state dye sensitized solar cell using the optimized polymer gel electrolyte was investigated. The optimized system of high ionic conductivity of 7mScm−1, with fill factor of 0.59, short-circuit density of 11.11mAcm−2, open-circuit voltage of 0.75V and the conversion efficiency of 4.9% under air mass 1.5 irradiation (100mWcm−2) was obtained. The long-term stability of the dye-sensitized solar cell (DSSC) during 600h was improved by using PEO/PMMA gel electrolyte relative to a liquid type electrolyte.

Effect of tapioca starch addition on rheological, thermal, and gelling properties of rice starch

The rheological, thermal, and gelling properties of blends of rice starch (RS) with tapioca starch (TS) at different RS/TS ratios (10/0, 9/1, 8/2, 7/3, 6/4, and 5/5) were examined. Steady and dynamic shear rheological tests indicated that the consistency index (K) and yield stress (σoc) of the RS–TS blends increased with an increase in the mixing ratio of TS while the dynamic moduli (G′ and G″) values decreased. Tan δ (ratio of G″/G′) values of all the blends were higher than that of RS, indicating that there is a more pronounced synergistic effect on the viscous properties of RS in the presence of TS. DSC studies found that the transition temperatures and enthalpies of gelatinization of the blends appeared to be greatly influenced by the addition of TS. The blend gels showed higher gel strength and also better freeze–thaw stability with a significant decrease in syneresis (%) in higher ratios of TS. In general, these results suggest that in the RS–TS blend systems, the addition of TS modified the rheological, thermal, and gelling properties of RS, and that these modifications were dependent on the mixing ratio of TS as well as the physical properties of the two component starches.

Effect of cryogenic freezing on textural properties and microstructure of rice flour/tapioca starch blend gel

Texture of rice flour (RF) gel was improved by blending with tapioca starch (TS). Fresh RF gel (40% w/w) fractured prematurely, while the RF/TS blend gel with equal weight ratio of RF and TS did not rupture under compression. Moreover, the blend gel showed the promising textural properties with the maximum hardness, and high cohesiveness and springiness. Thus, effects of cryogenic freezing and storage time on texture and microstructure of this blend gel were studied. Upon freezing and storage at −20°C up to 3months, the gel frozen via cryogenic freezing retained its integrity when compressed as a homogeneous distribution of small ice-rich domains was achieved. The slow-rate chest freezing, however, caused the gel fracture easily due to inhomogeneous microstructure with the presence of larger ice-rich domains. The results suggested that textural stability of the frozen RF/TS blend gel could be maintained with the use of cryogenic freezing due to the delay of phase separation.

Effects of corn fiber gum (CFG) on the pasting and thermal behaviors of maize starch

Corn fiber gum (CFG) was a novel arabinoxylan hydrocolloid and recent researches showed its considerable potential in food processing. In this study, the interactions of maize starch and CFG were studied. Maize starch/CFG blend gels were prepared from maize starch suspension mixing with 0.1%, 0.25%, 0.5%, 1.0% (w/w) CFG. The pasting and thermal properties, rheological properties, microstructure, leached amylose and swelling power characteristics were evaluated. Compared with the reference, CFG addition lowered peak viscosity and breakdown of the composite system, but increased final viscosity in RVA measurement. The swelling power and the amount of leached amylose of maize starch gels were reduced as the addition concentration of CFG increased. The thermal characteristics of maize starch/CFG mixtures varied insignificantly as determined in DSC heating process. Rheological parameters, such as storage modulus (G’) and loss modulus (G”), of the maize starches were observed to increase when CFG was present, supporting the hypothesis that the interaction between CFG and amylose could happen in the composite system. Confocal laser scanning microscopy (CLSM) confirmed changes in gels microstructure as starch components tended to be inhibited from leaching out of the granules when CFG was added, and the morphology of starch granule was more compact when CFG was added.

Pre-crosslinked polymeric collagen in 3-D models of mechanically stiff tissues: Blended collagen polymer hydrogels for rapid layer fabrication

Currently one factor hindering the development of collagen hydrogel constructs for tissue engineering is the mismatch between initial cellularity and mechanical strength. The main advantage of collagen hydrogel tissue constructs is their ability to support interstitially seeded cells. However, cells are sensitive to their environment, in particular, substrate stiffness, which cannot easily be replicated within hydrogels without cytotoxic cross-linking treatment. In this study, pre-crosslinked polymeric collagen fibrils are introduced as a starting material, thereby avoiding artificial cross-linking. Shear aggregation of this material in solution results in fibril alignment, but cell addition is only possible when polymeric collagen is blended with its monomeric counterparts to slow the aggregation of collagen fibrils. The hydrogel can then be brought to physiological collagen density by plastic compression. Interstitially seeded fibroblasts were supported for 14days. Although compression of blended gels resulted in some cell death due to increased rate of fluid expulsion, not normally seen in conventional collagen hydrogels, the surviving cell population recovers during subsequent culture. Importantly, the compression process can be controlled and customized to limit cell damage. This is the first report of native polymeric collagen used in a tissue engineering context, for the rapid production of a stiff collagen-cell constructs.

Gel polymer electrolyte-based on PVDF/fluorinated amphiphilic copolymer blends for high performance lithium-ion batteries

This paper describes the preparation and properties of PVDF/P(hexafluorobutyl methacrylate-co-poly(ethyleneglycol)methacrylate)(P(HFBMA-co-PEGMA)) blend gel polymer electrolyte (GPE) for high-performance lithium-ion batteries. The fluorinated amphiphilic copolymer, P(HFBMA-co-PEGMA), was synthesized by simple radical polymerization and then blended into poly(vinylidene fluoride) (PVDF) matrix via immersion phase inversion process. The composition, morphologies, liquid electrolyte uptake of the blend membranes and electrochemical properties of the corresponding GPEs were systematically investigated. It is found that the introduction of P(HFBMA-co-PEGMA) results in a slight increase in porosity, a reduction in crystallinity and better affinity with liquid electrolyte, which consequently lead to a substantial increase in liquid electrolyte uptake and ion conductivity. For the membrane with P(HFBMA-co-PEGMA)/PVDF mass ratio in 1.7/10, the liquid electrolyte uptake and ionic conductivity reach to 387% and 3.19 mS cm−1, respectively. In addition, the resulting GPE is electrochemically stable up to about 4.5 V (vs. Li+/Li).

Galactosylated reversible hydrogels as scaffold for HepG2 spheroid generation

Various galactosylated scaffolds have been developed for hepatocyte culture because galactose ligands help maintain cell viability, facilitate the formation of multicellular spheroids and help maintain a high level of liver-specific functions. However, it is difficult to harvest the cell spheroids generated inside the three-dimensional scaffolds for their further biological analysis and applications. Here we developed a new galactosylated hydrogel scaffold which solidifies in situ upon heating to physiological temperature, but liquefies again upon cooling back to room temperature. The new scaffold is composed of poly(N-isopropylacrylamide) (PNIPAM) microgel and poly(ethylene glycol) (PEG). Because of the thermosensitivity of PNIPAM microgel, the mixed dispersions gel upon heating and liquefy upon cooling. PEG was added to reduce the shrinkage of the gels. Part of the PNIPAM microgel was replaced with a galactosylated one to provide a series of blend gels with various galactose ligand contents. HepG2 cells, a human hepatocarcinoma cell line, were encapsulated in the in situ-formed gels. As expected, the cell viability increases with increasing content of galactose ligands. In addition, compact multicellular spheroids were obtained in gels containing galactose ligands, while loose spheroids formed in gel without galactose ligands. The cells cultured in galactose-containing gels also exhibit a higher level of liver-specific functions, in terms of both albumin secretion and urea synthesis, than those cultured in gel without these ligands. The new galactosylated scaffold not only promotes the formation of hepatocyte spheroids, but also allows for their harvest. By cooling back to room temperature to liquefy the gel, the hepatocyte spheroids can be facilely harvested from the scaffold. The reversible galactosylated scaffold developed here may be used for large scale fabrication of hepatocyte spheroids.

Graphene oxide sheet–polyaniline nanohybrids for enhanced photovoltaic performance of dye‐sensitized solar cells

ABSTRACTIn this study, photovoltaic (PV) properties of dye‐sensitized solar cells (DSSCs) incorporated with graphene oxide nanosheet‐polyaniline (GOS‐PANI) nanohybrid/poly(ethylene oxide) (PEO) blend gel electrolytes were investigated. Chemical structure and composition of GOS‐PANI nanohybrids were characterized by Raman spectroscopy and X‐ray photoelectron spectroscopy. The images of transmission electron microscopy revealed that PANI nanorods were anchored to the single‐layered GOS for the GOS‐PANI nanohybrids. Ionic conductivities of the GOS‐PANI/PEO–based gel electrolytes were measured using a conductivity meter. The electrochemical catalytic activities of the GOS‐PANI nanohybrids were determined through cyclic voltammetry. These GOS‐PANI nanohybrids were served as the extended electron transfer materials and catalyst for the electrochemical reduction of I3−. Due to the enhancement of the ionic conductivity and electrochemical catalytic activity of the gel electrolyte, better PV performance was observed for the DSSCs based on the GOS‐PANI containing electrolytes as compared to the pristine PEO electrolyte‐based DSSC sample. Moreover, PV performances of the GOS‐PANI/PEO–based DSSCs were closely related to the PANI content of GOS‐PANI nanohybrids. The highest photo‐energy conversion efficiency (5.63%) was obtained for an optimized GOS‐PANI/PEO (5:95, w/w) blend gel electrolyte‐based DSSC sample. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 321–332