10 documents found, page 1 of 1
Fluorescent Bioactive Corrole Grafted-Chitosan Films
Barata, Joana F. B.; Pinto, Ricardo J. B.; Vaz Serra, Vanda I. R. C.; Silvestre, Armando J. D.; Trindade, Tito; Neves, Maria Graca P. M. S.Transparent corrole grafted-chitosan films were prepared by chemical modification of chitosan with a corrole macrocycle, namely, 5,10,15-tris(pentafluorophenyl)corrole (TPFC), followed by solvent casting. The obtained films were characterized in terms of absorption spectra (UV-vis), FLIM (fluorescence lifetime imaging microscopy), structure (FTIR, XPS), thermal stability (TGA), thermomechanical properties (DMA)...
Bioactive transparent films based on polysaccharides and cholinium carboxylate ...
Tome, Liliana C.; Silva, Nuno H. C. S.; Soares, Hugo R.; Coroadinha, Ana S.; Sadocco, Patrizia; Marrucho, Isabel M.; Freire, Carmen S. R.Novel antibacterial and biocompatible transparent films based on chitosan or pullulan and two bioactive ionic liquids (ILs), cholinium hexanoate and cholinium citrate, were prepared. These ILs were selected based on their MIC values against several microbial strains, film-forming ability when blended with the polysaccharides and biocompatibility against designated human cell lines. The films were obtained throu...
Antimicrobial pullulan derivative prepared by grafting with 3-aminopropyltrimet...
Fernandes, Susana C. M.; Sadocco, Patrizia; Causio, Jessica; Silvestre, Armando J. D.; Mondragon, Inaki; Freire, Carmen S. R.In the present work, we propose a simple and straightforward procedure to prepare antibacterial transparent pullulan films by functionalization of pullulan powder with 3-aminopropyltrimethoxysilane. The introduction of active aminopropyl groups into the pullulan polymeric backbone imparts antimicrobial activity against Gram-positive (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli). In addit...
The role of nanocellulose fibers, starch and chitosan on multipolysaccharide ba...
Tome, Liliana C.; Fernandes, Susana C. M.; Perez, Denilson Silva; Sadocco, Patrizia; Silvestre, Armando J. D.; Pascoal Neto, Carlos; Marrucho, Isabel M.Thin nanocomposite films of thermoplastic starch, chitosan and cellulose nanofibers (bacterial cellulose or nanofibrillated cellulose) were prepared for the first time by solvent casting of water based suspensions of the three polysaccharides. The role of the different bioploymers on the final properties (thermal stability, transparency, mechanical performance and antimicrobial activity) of the films was relate...
Antibacterial Activity of Nanocomposites of Copper and Cellulose
Pinto, Ricardo J. B.; Daina, Sara; Sadocco, Patrizia; Neto, Carlos Pascoal; Trindade, TitoThe design of cheap and safe antibacterial materials for widespread use has been a challenge in materials science. The use of copper nanostructures combined with abundant biopolymers such as cellulose offers a potential approach to achieve such materials though this has been less investigated as compared to other composites. Here, nanocomposites comprising copper nanofillers in cellulose matrices have been prep...
Bioinspired Antimicrobial and Biocompatible Bacterial Cellulose Membranes Obtai...
Fernandes, Susana C. M.; Sadocco, Patrizia; Aonso-Varona, Ana; Palomares, Teodoro; Eceiza, Arantxa; Silvestre, Armando J. D.; Mondragon, InakiThere has been a great deal of interest in the use of nanostructured bacterial cellulose membranes for biomedical applications, including tissue implants, wound healing, and drug delivery. However, as bacterial cellulose does not intrinsically present antimicrobial properties, in the present study, antimicrobial bacterial cellulose membranes were obtained by chemical grafting of aminoalkyl groups onto the surfa...
Antibacterial paper based on composite coatings of nanofibrillated cellulose an...
Martins, Natercia C. T.; Freire, Carmen S. R.; Neto, Carlos Pascoal; Silvestre, Armando J. D.; Causio, Jessica; Baldi, Giovanni; Sadocco, PatriziaNew composites of nanofibrillated cellulose (NFC) and ZnO nanoparticles (NP) have been prepared by electrostatic assembly in aqueous medium and using polyelectrolytes as macromolecular linkers. Selected NFC/ZnO systems were employed as fillers in starch based coating formulations for Eucalyptus globulus-based paper sheets. Using this method, antibacterial paper with low content of ZnO (<0.03%) and slight improv...
Electrostatic assembly of Ag nanoparticles onto nanofibrillated cellulose for a...
Martins, Natércia C. T.; Freire, Carmen S. R.; Pinto, Ricardo J. B.; Fernandes, Susana C. M.; Neto, Carlos Pascoal; Silvestre, Armando J. D.Nanofibrillated cellulose offers new technological solutions for the development of paper products. Here, composites of nanofibrillated cellulose (NFC) and Ag nanoparticles (NP) were prepared for the first time via the electrostatic assembly of Ag NP (aqueous colloids) onto NFC. Distinct polyelectrolytes have been investigated as macromolecular linkers in order to evaluate their effects on the building-up of Ag...
Preparation and characterization of novel biodegradable composites based on acy...
Fernandes, Tânia F.; Trovatti, Eliane; Freire, Carmen S.R.; Silvestre, Armando J.D.; Neto, Carlos Pascoal; Gandini, Alessandro; Sadocco, PatriziaThe preparation and characterization of biodegradable composite materials with improved properties based on poly(ethylene sebacate) (PES) and acylated cellulose fibers is reported. These biocomposites showed improved mechanical properties, as evidenced by the increase in both elastic and Young moduli and in the tensile strength, and also showed low water sensitivity and a high biodegradability rate. These novel ...
Antibacterial activity of nanocomposites of silver and bacterial or vegetable c...
Pinto, Ricardo J. B.; Marques, Paula A. A. P.; Pascoal Neto, Carlos; Trindade, Tito; Daina, Sara; Sadocco, PatriziaCellulose/Ag nanocomposites were prepared using two distinct methodologies and two cellulose substrates: vegetable and bacterial cellulose. These nanocomposites were characterized in terms of their morphology and chemical composition. Detailed studies on the antibacterial activity of these materials were carried out for Bacillus subtilis, Staphylococcus aureus and Klebsiella pneumoniae. Silver nanoparticles pre...