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Human hepatocytes in three-dimensional culture on Innovative biopolymeric scaffolds as a useful system for in vitro toxicology tests
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HUMAN HEPATOCY
TES IN THREE-
DIMENSIONAL CULTURE ON INNOVATIVE
BIOPOLYMERIC SCAFFOLDS
AS AN USEFUL SYSTEM
FOR
IN VITRO
TOXICOLOGY TESTS
Stampella A. (a), Massimi M. (b), Barbetta A.
(c), Rizzitelli G. (c), Dentini M. (c), Conti
Devirgiliis L. (a)
(a) Department of Biology and Biotechnology Charles Darwin, Sapienza University of
Rome, Rome, Italy
(b) Department of Basic and Applied Biology, University of L’Aquila, L’Aquila, Italy
(c) Department of Chemistry, Sapienza University of Rome, Rome, Italy
Many innovative biomaterials have recently be developed as scaffolds to replace
physiological matrix components and their im
provement has led to significant advances in
culture techniques in terms of cell survival, quantitative expansion, maintenance of
differentiated phenotype and specific cell functions. A key point in achieving these goals
has been to maintain a three-dimensional culture and the typical cyto-architecture of the
tissue by improving the extracellular matrix geometry and by promoting cell-cell contacts
and reciprocal adhesions. These bio-artificial
systems represent a real hope as functional
substitutes for damaged organs and tissues and have provoked a great interest in the field of
regenerative medicine. Concerning hepatocyte cultures, since the liver is the main organ
involved in detoxification processes and in the defence of organisms against harmful
molecules, in addition to their biomedical applications, these systems can be utilized as
invaluable tool for toxicology tests for analyzing the effects on metabolism of new drugs,
or for screening potentially toxic substances. The aim of our research was to identify the
most suitable biomaterial for the technological applications with hepatocytes. Since the
possibility to improve the performance of thes
e systems depends strongly on the methods
used to create the scaffolds, here we analyzed
porous matrices made of gelatin or blends of
gelatin and glycosaminoglycans, obtained with different methods for the culture of the C3A
cell line, considered a
good model of human hepatocytes. Scaffolds were obtained using
either a concentrated emulsi
on-templating technique known as High Internal Phase
Emulsion (HIPE) or a gas foaming technique; the latter method uses an inert gas instead of
the internal liquid phase toluene, avoiding the use of organic solvent and allowing the
creation of scaffolds with la
rger pores and interconnections. Cell viability was analysed
using MTS and LDH assays; ultrastructural morphology and three-dimensional cell
organization into the scaffold were assessed by SEM; albumin and urea secretion, as the
main metabolic markers of hepatocyte functions, were monitored using, respectively, an
ELISA kit and a colorimetric assay. Finally
Cytochrome P450-3A4 activity was quantified
by a luminescent method. Values of activity of this important enzyme of the detoxification
system, obtained in the absence or in the pr
esence of specific inducing molecules, were
compared between the different culture conditions
Aqueous solution properties of bacterial poly-gamma-D-glutamate
No full textA preliminary physico-chemical characterization of a bacterial poly-γ-glutamate sample (96% D-glutamic acid content), γ-D-PGA, in dilute aqueous solutions has been carried out by means of potentiometric, viscosimetric, infrared and chiroptical spectroscopic experiments. The biopolymer exhibits properties strikingly dependent on a number of parameters, mainly: polymer concentration, pH, ionic strength, and nature of added salt. In dilute solutions (polymer concentration around 0.1% w/V) and for pH > 7, γ-D-PGA chains assume elongated, stiff conformations while upon protonation (pH < 3) globular states would prevail. Addition of divalent counterions (Ca(II)) also leads to compact γ-D-PGA conformations
CIRCULAR-DICHROISM EVIDENCE FOR A STEREOSPECIFIC COMPLEXATION REACTION IN COPPER(II) CHELATES OF POLY-ALPHA-AMINO-ACID LIGANDS
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Stabilità Conformazionale in Mezzo Acquoso Diluito del Polisaccaride Succinoglicano e dei Suoi Semplici Derivati
No full textOn the pH-induced conformational transition of the exocellular polysaccharide from Rhizobium trifolii strain TA-1
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