title: Injectable pectin hydrogels produced by internal gelation: pH dependence of gelling and rheological properties.
abstract: The production of injectable pectin hydrogels by internal gelation with calcium carbonate is proposed. The pH of pectin was increased with NaOH or NaHCO3 to reach physiological values. The determination of the equivalence point provided evidence that the pH can be more precisely modulated with NaHCO3 than with NaOH. Degradation and inability to gel was observed for pectin solutions with pH 5.35 or higher. Therefore, pectin solutions with pH values varying from 3.2 (native pH) to 3.8 were chosen to produce the gels. The increase of the pH for the crosslinked hydrogels, as well as the reduction of the gelling time and their thickening, was dependent upon the amount of calcium carbonate, as confirmed by rheology. Hydrogel extracts were not cytotoxic for L-929 fibroblasts. On the overall, the investigated formulations represent interesting injectable systems providing an adequate microenvironment for cell, drug or bioactive molecules delivery.
authors: FEUP - Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias s/n, 4200-465 Porto, Portugal; Laboratorio di Biomateriali, Dipartimento di Chimica, Materiali e Ingegneria Chimica 'G. Natta' and Unità di Ricerca Consorzio INSTM, Politecnico di Milano, Piazza L. da Vinci, 32, 20133 Milan, Italy.
authors: Helena R
authors: HR
authors: Moreira
authors: Laboratorio di Biomateriali, Dipartimento di Chimica, Materiali e Ingegneria Chimica 'G. Natta' and Unità di Ricerca Consorzio INSTM, Politecnico di Milano, Piazza L. da Vinci, 32, 20133 Milan, Italy. Electronic address: fabiola.munarin@polimi.it.
authors: Fabiola
authors: F
authors: Munarin
authors: Laboratorio di Biomateriali, Dipartimento di Chimica, Materiali e Ingegneria Chimica 'G. Natta' and Unità di Ricerca Consorzio INSTM, Politecnico di Milano, Piazza L. da Vinci, 32, 20133 Milan, Italy; Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy.
authors: Roberta
authors: R
authors: Gentilini
authors: Dept. of Molecular Medicine, Center for Tissue Engineering (C.I.T.), INSTM UdR of Pavia, University of Pavia, 27100 Pavia, Italy; Dept. of Occupational Medicine, Ergonomy and Disability, Lab. Nanothecnology, Salvatore Maugeri Foundation, IRCCS, 27100 Pavia, Italy.
authors: Livia
authors: L
authors: Visai
authors: FEUP - Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias s/n, 4200-465 Porto, Portugal; INEB - Instituto de Engenharia Biomedica,Universidade do Porto, Rua do Campo Alegre, 823, 4150-180 Porto, Portugal; Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Largo Prof. Abel Salazar, 2, 4099-003 Porto, Portugal.
authors: Pedro L
authors: PL
authors: Granja
authors: Laboratorio di Biomateriali, Dipartimento di Chimica, Materiali e Ingegneria Chimica 'G. Natta' and Unità di Ricerca Consorzio INSTM, Politecnico di Milano, Piazza L. da Vinci, 32, 20133 Milan, Italy.
authors: Maria Cristina
authors: MC
authors: Tanzi
authors: Laboratorio di Biomateriali, Dipartimento di Chimica, Materiali e Ingegneria Chimica 'G. Natta' and Unità di Ricerca Consorzio INSTM, Politecnico di Milano, Piazza L. da Vinci, 32, 20133 Milan, Italy.
authors: Paola
authors: P
authors: Petrini
mesh_terms: D005782:Gels / Q000138:chemical synthesis / Q000737:chemistry; D020100:Hydrogels / Q000138:chemical synthesis* / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D010368:Pectins / Q000138:chemical synthesis* / Q000737:chemistry; D012212:Rheology
chemical_list: D005782:Gels; D020100:Hydrogels; D010368:Pectins
keywords: Biomaterials; Internal gelation; Natural polymers; Pectin; Tissue engineering