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In this work, a new class of fourth-generation, zero ozone depletion potential, hydrofluoroolefin-based blowing agents were used to prepare phenolic foam. While hydrofluoroolefin blowing agents have been used previously to prepare polyurethane foams, few studies have been reported on their use in phenolic foams. We introduce an effective method for foam preparation using two low-boiling blowing agents, cis-1,1,1,4,4,4-hexafluoro-2-butene and trans-1,1,1,4,4,4-hexafluoro-2-butene, and their combinations with hexane. Traditionally, phenolic foams have been prepared using chlorofluorocarbons and hydrochlorofluorocarbons, which can have harmful effects on the environment due to their high ozone depletion potential or global warming potential. Conductor-like screening model for real solvents (COSMO-RS) modeling studies were performed to understand the effects of different blowing agent combinations on their boiling points. A series of phenolic foams were prepared by varying the concentration of the hydrofluoroolefin and the hydrofluoroolefin–hexane blowing agent combinations. The concentrations of the surfactant, Agnique CSO 30, and the toughening agent, polyethylene glycol, were also varied to yield a formulation with the optimal properties. The foams formulated with the hydrofluoroolefin–hexane mixture displayed a higher compressive strength and a lower thermal conductivity than those prepared with either hydrofluoroolefin or hexane alone. The cell microstructure of all the foams was examined using scanning electron microscopy. By introducing flexible chains into the resin matrix, PEG facilitates proper distribution of hydrofluoroolefin–hexane blowing agents and other reagents and thereby increases the mechanical strength of the foam. [ABSTRACT FROM AUTHOR]

Self assembled hybrid polyelectrolyte complex (PEC) nanoparticles are prepared from cationically modified gelatin and sodium alginate (Alg) by electrostatic complexation between the polymers. Cationised gelatin (CG) is prepared by the reaction of gelatin with ethylenediamine. Structural changes in gelatin, after modification with ethylenediamine are investigated by XRD and (1)H NMR spectroscopy. Hybrid polyelectrolyte nanoparticles, labeled CG/Alg, are prepared by simple mixing of CG and Alg. CG/Alg complex shows spherical morphology as confirmed by scanning electron microscopy. These polyelectrolyte complex nanoparticles can be used for the encapsulation and delivery of natural antioxidant curcumin to carcinoma cells. CG/Alg nanoparticles show curcumin encapsulation efficiency of 69% and exhibit sustained release of curcumin in vitro. Anticancer activity of curcumin loaded CG/Alg nanoparticles towards MCF-7 cells is disclosed by MTT assay. Intracellular uptake of the drug encapsulated nanoparticles is confirmed by fluorescent imaging., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Curcumin, a widely studied hydrophobic polyphenol with anticancer potential is loaded in gum arabic aldehyde-gelatin (GA Ald-Gel) nanogels to improve its bioavailability and therapeutic efficacy towards cancer cells. Physicochemical properties of the curcumin loaded GA Ald-Gel nanogels are investigated by different techniques including dynamic light scattering (DLS), NMR spectroscopy and scanning electron microscopy (SEM). These nanogels exhibit hydrodynamic diameter of 452±8nm with a zeta potential of -27mV. The nanogels possess an encapsulation efficiency of 65±3%. Potential of the nanogels for controlled release of curcumin is illustrated by in vitro drug release studies. Hemocompatibility and cytocompatibility of the drug loaded nanogels are evaluated. In vitro cytotoxicity of the bare and curcumin loaded nanogels are analyzed by MTT assay towards MCF-7 cells. The results manifest that curcumin loaded nanogels induce toxicity in MCF-7 cells. Confocal laser scanning microscopy (CLSM) studies indicate in vitro cellular uptake of the nanogels in MCF-7 cells. All these results prove the suitability of the curcumin loaded GA Ald-Gel nanogels for cancer therapy., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Galactosylated alginate-curcumin conjugate (LANH2-Alg Ald-Cur) is synthesized for targeted delivery of curcumin to hepatocytes exploiting asialoglycoprotein receptor (ASGPR) on hepatocytes. The synthetic procedure includes oxidation of alginate (Alg), modification of lactobionic acid (LA), grafting of targeting group (modified lactobinic acid, LANH2) and conjugation of curcumin to alginate. Alginate-curcumin conjugate (Alg-Cur) without targeting group is also prepared for the comparison of properties. LANH2-Alg Ald-Cur self assembles to micelle with diameter of 235 ± 5 nm and zeta potential of -29 mV in water. Cytotoxicity analysis demonstrates enhanced toxicity of LANH2-Alg Ald-Cur over Alg-Cur on HepG2 cells. Cellular uptake studies confirm that LANH2-Alg Ald-Cur can selectively recognize HepG2 cells and shows higher internalization than Alg-Cur conjugate. Results indicate that LANH2-Alg Ald-Cur conjugate micelles are suitable candidates for targeted delivery of curcumin to HepG2 cells., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Curcumin is conjugated to gum arabic, a highly water soluble polysaccharide to enhance the solubility and stability of curcumin. Conjugation of curcumin to gum arabic is confirmed by (1)H NMR, fluorescence and UV spectroscopy studies. The conjugate self assembles to spherical nano-micelles (270 ± 5 nm) spontaneously, when dispersed in aqueous medium. Spherical morphology of the self assembled conjugate is evidenced by field emission scanning electron microscopy and transmission electron microscopy. The self assembly of the amphiphilic conjugate into micelle in aqueous medium significantly enhances the solubility (900 fold of that of free curcumin) and stability of curcumin in physiological pH. The anticancer activity of the conjugate micelles is found to be higher in human hepatocellular carcinoma (HepG2) cells than in human breast carcinoma (MCF-7) cells. The conjugate exhibits enhanced accumulation and toxicity in HepG2 cells due to the targeting efficiency of the galactose groups present in gum arabic., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Galactosylated pullulan-curcumin conjugate (LANH2-Pu Ald-Cur SA) is developed for target specific delivery of curcumin to hepatocarcinoma cells by five step synthetic strategy, which includes oxidation of pullulan (Pu Ald), introduction of amino group to the targeting ligand (LANH2), grafting of the LANH2 to Pu Ald, modification of curcumin (Cur SA) and conjugation of Cur SA to pullulan. Nongalactosylated pullulan-curcumin conjugate (Pu-Cur SA) is also prepared to compare the enhancement in cytotoxicity offered by the targeting group. Both LANH2-Pu Ald-Cur SA and Pu-Cur SA conjugates could self assemble to micelle in water with hydrodynamic diameters of 355±9nm and 363±10nm, respectively. Both conjugates show spherical morphology and enhance stability of curcumin in physiological pH. Compared to Pu-Cur SA, LANH2-Pu Ald-Cur SA exhibits higher toxicity and internalization towards HepG2 cells. This indicates the enhanced uptake of LANH2-Pu Ald-Cur SA conjugate via ASGPR (asialoglycoprotein receptor) mediated endocytosis into HepG2 cells., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Gelatin-gum arabic aldehyde nanogels designed by a nanoreactor concept using inverse miniemulsion technique were reported. Stable separate miniemulsions were prepared from gelatin (Gel) and gum arabic aldehyde (GAA). These emulsions were intermixed under sonication to obtain cross-linked nanogels. During fusion, cross-linking occurred between aldehyde groups of GAA and amino groups of gelatin. The concentration of the surfactant and weight fraction of water in the inverse miniemulsion was optimised so as to yield nanogels with controlled particle size. Properties of the nanogels were studied by FT-IR spectroscopy, particle size analysis and XRD. Surface morphology of the nanogels was established by Scanning Electron Microscopy (SEM). SEM and particle size analysis confirmed that nanogels possess spherical morphology with an average diameter of 151 ± 6 nm. Hemolysis property of the nanogels was examined and the results indicated that the nanogels were hemocompatible. The in vitro cytotoxicity of the nanogels towards MCF-7 cells was evaluated by MTT assay and the nanogels showed nontoxic behaviour towards the cells. All these studies confirm that these nanogels are potential candidates in applications such as drug and gene delivery., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Nanogels were developed from alginic aldehyde and gelatin by an inverse miniemulsion technique. Stable inverse miniemulsions were prepared by sonication of noncontinuous aqueous phase (mixture of alginic aldehyde and gelatin) in a continuous organic phase (Span 20 dissolved in cyclohexane). Cross-linking occurred between alginic aldehyde (AA) and gelatin (gel) in the presence of borax by Schiff's base reaction during the formation of inverse miniemulsion. The effects of surfactant (Span 20) concentration, volume of the aqueous phase and AA/gel weight ratio on the size of the alginic aldehyde-gelatin (AA-gel) nanoparticles were studied. Nanogels were characterized by DLS, FT-IR spectroscopy, TGA, SEM and TEM. DLS, TEM and SEM studies demonstrated nanosize and spherical morphology of the nanogels. Hemocompatibility and in vitro cytocompatibility analyses of the nanogels proved their nontoxicity. The results indicated the potential of the present nanogel system as a candidate for drug- and gene-delivery applications., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Development of liver support systems has become one of the most investigated areas for the last 50 years because of the shortage of donor organs for orthotopic liver transplantations. Bioartificial liver (BAL) device is one of the alternatives for liver failure which provides a curing method and support patients to recover from certain liver failure diseases. The biological compartment of BAL is called the bioreactor where functionally active hepatocytes are maintained to support the liver specific functions. We have developed a packed bed bioreactor with a cytocompatible, polysaccharide-protein hybrid scaffold. The scaffold prepared from gelatin and gum Arabic acts as a packed bed matrix for hepatocyte culture. Quantitative evaluation of the hepatocytes cultured using packed bed bioreactor demonstrated that cells maintained liver specific functions like albumin and urea synthesis for seven days. These results indicated that the system can be scaled up to form the biological component of a bioartificial liver., (Copyright © 2014 Elsevier B.V. All rights reserved.)

The present work deals with development of modified gum arabic cross-linked gelatin scaffold for cell culture. A new biocompatible scaffold was developed by cross-linking gelatin (Gel) with gum arabic, a polysaccharide. Gum arabic was subjected to periodate oxidation to obtain gum arabic aldehyde (GAA). GAA was reacted with gelatin under appropriate pH to prepare the cross-linked hydrogel. Cross-linking occurred due to Schiff's base reaction between aldehyde groups of oxidized gum arabic and amino groups of gelatin. The scaffold prepared from the hydrogel was characterized by swelling properties, degree of cross-linking, in vitro degradation and scanning electron microscopy (SEM). Cytocompatibility evaluation using L-929 and HepG2 cells confirmed non-cytotoxic and non-adherent nature of the scaffold. These properties are essential for generating multicellular spheroids and hence the scaffold is proposed to be a suitable candidate for spheroid cell culture., (Copyright © 2014 Elsevier B.V. All rights reserved.)