Search results for "GELS"

PhD revisited : Poetry : Prima Vista. Reader-Response Research on Poetry in a Foreign Language Context

2019

SINTESI E PROPRIETÁ DI SALI ORGANICI POLICATIONICI UTILIZZATI COME MEZZI DI REAZIONE

Highly robust and selective system for water pollutants removal: How to transform a traditional photocatalyst into a highly robust and selective syst…

2019

Highly porous monolithic aerogels based on ZnO photocatalyst and syndiotactic polystyrene (s-PS) were obtained by supercritical CO2 treatment of ZnO/s-PS gels. The prepared aerogels were characterized and their photocatalytic activity was evaluated using phenol and toluene as water pollutant models. The s-PS nanoporous crystalline phase, able to absorb pollutant molecules, was proven to be necessary to ensure high photocatalytic efficiency as the aerogel acts not only as a support, but also as pollutant pre-concentrator. The reusability of ZnO/s-PS aerogels is also strong showing no decrease in photocatalytic activity after six consecutive degradation trials. Finally, the aerogel matrix pre…

Embryotoxic potential of persistent organic pollutants extracted from tissues of guillemots (Uria aalge) from the Baltic Sea and the Atlantic Ocean

2002

The Baltic Sea is a heavily polluted area. To assess the current contaminant pressure on the common guillemot (Uria aalge) living there, whole-body extracts of guillemots from the Baltic Sea were prepared and subdivided over six fractions, which differed in composition due to lipophilicity and polarity of the contaminants. The fractions were tested in the chicken embryo assay and compared to fractions of Atlantic guillemot extracts. Fertilized chicken eggs were injected with 0.03, 0.3, or 3 bird egg equivalents (BEQ) of the contaminants present in the fractions and then incubated for 19 d. Endpoints were selected to cover several mechanisms that may play a role in reproductive failures of f…

SPIONs embedded in polyamino acid nanogels to synergistically treat tumor microenvironment and breast cancer cells.

2018

Abstract The extremely complex tumor microenvironment (TME) in humans is the major responsible for the therapeutic failure in cancer nanomedicine. A new concept of disease-driven nanomedicine, henceforth named “Theranomics”, which attempts to target cancer cells and TME on the whole, represents an attractive alternative. Herein, a nanomedicine able to co-deliver doxorubicin and a tumor suppressive proteolytic protein such as collagenase-2 was developed. We successfully obtained superparamagnetic nanogels (SPIONs/Doco@Col) via the intermolecular azide-alkyne Huisgen cycloaddition. We demonstrated that a local ECM degradation and remodeling in solid tumors by means of collagenase-2 could enha…

Ciprofloxacin releasing gellan gum/polydopamine based hydrogels with near infrared activated photothermal properties.

2021

Abstract In this work, with the aim to obtain a wound dressing hydrogel, an amine derivative of gellan gum was crosslinked in the presence of 4arm-polyethylenglycole-vinylsulfone. Through this easy and reproducible chemical procedure, a hydrogel with advanced elastic properties and hydrolytic resistance under physiological conditions was obtained. The incorporation of different quantities of polydopamine in the gelling solutions allows to obtain different hydrogels with marked photothermal properties when irradiated with a laser in the near infrared at 810 nm. The organic nanoparticles, reacting with the amino groups of the polysaccharide derivative, contribute to increase the storage modul…

Leach-Proof Sol–Gel Microcapsules as Curing Agents for One-Pot Thermosetting Resins

2013

The sol-gel microencapsulation of free-radical initiator benzoyl peroxide in sol-gel methyl-modified silica microcapsules of core/shell geometry allows curing of acrylate-based polyurethane and polyester resin formulations sprayed from a pressurized can without the need to compartmentalize reactants from the initiator to cross-link. These results open the route to widespread application of sol-gel microcapsules to efficiently cure polymer and composite mixtures that are widely used as functional coatings, molding compounds, adhesives, and sealants.

Polygalacturonate hydrogels using Fe2+ as cross-linkers : impact of the local association mode on gelation mechanisms, control of the multiscale stru…

2018

This pHD thesis describes the design of polygalacturonate hydrogels (polyGal) cross-linked by the Fe2+ cations, and their experimental characterization from the molecular scales up to the macroscopic scales, by combining EXAFS spectroscopy, Small Angle Neutron Scattering (SANS) and rheological measurements. We designed a robust gelling protocol that allowed to obtain reproducible cylindrical gels with controlled concentration gradients from the lower side to the upper side of the gel. The ratio [Fe]/[Gal] has a constant value all along the gel, which demonstrate that the Fe2+ cations are associated with 4 galacturonate units. The comparison of EXAFS measurements and molecular dynamics simul…

Crosslinked α,β-Polyasparthydrazide Micromatrices for Controlled Release of Anticancer Drugs

1995

The preparation of new hydrogels by the reaction of α,β- polyasparthydrazide and glutaraldehyde is reported. A different crosslinking degree was obtained by varying the ratio crosslinking agent/polymer which influenced the swelling behavior of the gel. 5-Fluorouracil, was incorporated into the matrices during the crosslinking reaction and in vitro release studies were performed in simulated gastric juice (pH 1.1) and pH 7.4 buffer solution. The hydrogels prepared were chemically stable in the dissolution media. The observed data show the potential application of these new matrices for peroral administration of anticancer agents.

Biodegradable and pH-sensitive hydrogels for potential colon-specific drug delivery: Characterization and in vitro release studies

2008

A novel pH-sensitive and biodegradable composite hydrogel, based on a methacrylated and succinic derivative of dextran, named Dex-MA-SA, and a methacrylated and succinic derivative of alpha,beta-poly( N-2-hydroxyethyl)- DL-aspartamide (PHEA), named PHM-SA, was produced by photocross-linking. The goal was to obtain a colon-specific drug delivery system, exploiting both the pH-sensitive behavior and the colon-specific degradability. The hydrogel prepared with a suitable ratio between the polysaccharide and the polyaminoacid was characterized regarding its swelling behavior in gastrointestinal simulated conditions, chemical and enzymatic degradability, interaction with mucin, and cell compatib…