Search results for "Hydrogel"

Solvation of a probe molecule by fluid supercooled water in a hydrogel at 200 K

2008

By combining electron paramagnetic resonance (EPR) measurements on a nitroxide probe and differential scanning calorimetry (DSC), we demonstrate existence of liquid supercooled water in a silica hydrogel with high hydration level down to temperatures of at least 198 K. Besides the major fraction of liquid supercooled water, a minor fraction crystallizes at about 236 K during cooling and melts at 246 K during heating. The liquid domains are of sufficient size to solvate the nearly spherical paramagnetic probe molecule TEMPO with a diameter of about 6 angstrom. Analysis of EPR spectra provides the rotational correlation time of the probe that is further used to compare the viscosity of the su…

A Calorimetric and Viscosimetric Study for the Characterization of Pectin Hydrogels. Application in the field of Cultural Heritage

2009

Modulating carbohydrate-based hydrogels as viscoelastic lubricant substitute for articular cartilages

2017

Viscosupplementation is a therapeutic approach for osteoarthritis treatment, where the synovial fluid, the natural lubricant of the joints, is replaced by viscoelastic solutions with rheological properties comparable or better than the starting material. This study presents the development of an innovative platform for viscosupplementation, based on the optimization of polysaccharide-based colloidal hydrogel, aiming to reduce on-site enzyme degradation and enhance the possibility of hyaluronic acid substitution with alternative biomaterials. Catanionic vesicles are proposed as physical crosslinker that can guarantee the formation of a 'soft', tunable network, offering a dual-therapeutic app…

Morphogenetically active scaffold for osteochondral repair (Polyphosphate/alginate/N,O-carboxymethyl chitosan)

2016

Here we describe a novel bioinspired hydrogel material that can be hardened with calcium ions to yield a scaffold material with viscoelastic properties matching those of cartilage. This material consists of a negatively charged biopolymer triplet, composed of morphogenetically active natural inorganic polyphosphate (polyP), along with the likewise biocompatible natural polymers N,O-carboxymethyl chitosan (N,O-CMC) and alginate. The porosity of the hardened scaffold material obtained after calcium exposure can be adjusted by varying the pre-processing conditions. Various compression tests were applied to determine the local (nanoindentation) and bulk mechanical properties (tensile/compressio…

κ-Carrageenan and PVA blends as bioinks to 3D print scaffolds for cartilage reconstruction.

2022

3D printing of polymeric scaffolds and autologous stem cells is a promising tool for damaged facial cartilage reconstruction surgeries. To this end, suitable bioinks are needed to generate scaffolds with the required morphological and functional features. We formulated hydrogel bioinks using k-Carrageen (kC) and poly(vinyl alcohol) (PVA) in three different weight ratios. The kC gives the systems the ability to undergo rapid sol-to-gel transitions upon cooling from 60 °C and above to body temperature, while the PVA is used as rheology modifier and porogen. The latter is crosslinked after molding or printing by freeze-thaw cycling for 1 day (FT1) or 5 days (FT5). To select the most suitable f…

Biocompatible hydrogels based on hyaluronic acid cross-linked with a polyaspartamide derivative as delivery systems for epithelial limbal cells.

2011

The aim of this work was to evaluate the potential use of hydrogels based on hyaluronic acid (HA) chemically cross-linked with α,β-poly(N-2-hydroxyethyl) (2-aminoethylcarbamate)-D,L-aspartamide (PHEA-EDA) as substitutes for the amniotic membrane able to release limbal cells for corneal regeneration. Hydrogels, shaped as films, with three different molar ratios (X) between PHEA-EDA and HA (X = 0.5, 1.0 and 1.5) have been investigated. First, it has been evaluated their swelling ability, hydrolytic resistance in simulated physiological fluid and cell compatibility by using human dermal fibroblasts chosen as a model cell line. Then adhesion studies in comparison with collagen gel, have been pe…

Hyaluronic acid based nanohydrogels fabricated by microfluidics for the potential targeted release of Imatinib: Characterization and preliminary eval…

2019

Abstract Microfluidics is emerging as an innovative technique for the “on chip” fabrication of nanoparticles for drug delivery applications. Here, by using an amphiphilic derivative of hyaluronic acid as a starting macromolecule, nanohydrogels loaded with Imatinib were produced by the microfluidic procedure in order to develop an innovative therapeutic tool for the treatment of retinal neovascularization. Both cyRGDC functionalized and non-functionalized nanohydrogels were designed and fabricated by using the same technique. The targeting efficiency of the obtained nanosystems was studied in vitro on human retinal pigment epithelial cells (HRPEpiC) and human umbilical vein endothelial cells…

In-situ gelling xyloglucan formulations as 3D artificial niche for adipose stem cell spheroids.

2020

Abstract Three-dimensional spheroidal cell aggregates of adipose stem cells (SASCs) are a distinct upstream population of stem cells present in adipose tissue, with enhanced regeneration properties in vivo. The preservation of the 3D structure of the cells, from extraction to administration, can be a promising strategy to ensure optimal conditions for cell viability and maintenance of stemness potential. With this aim, an artificial niche was created by incorporating the spheroids into an injectable, in-situ gelling solution of partially degalactosylated xyloglucan (dXG) and an ad hoc formulated culture medium for the preservation of stem cell spheroid features. The evolution of the mechani…

Effect of bioglass on growth and biomineralization of SaOS-2 cells in hydrogel after 3D cell bioprinting.

2014

We investigated the effect of bioglass (bioactive glass) on growth and mineralization of bone-related SaOS-2 cells, encapsulated into a printable and biodegradable alginate/gelatine hydrogel. The hydrogel was supplemented either with polyphosphate (polyP), administered as polyP • Ca2+-complex, or silica, or as biosilica that had been enzymatically prepared from ortho-silicate by silicatein. These hydrogels, together with SaOS-2 cells, were bioprinted to computer-designed scaffolds. The results revealed that bioglass (nano)particles, with a size of 55 nm and a molar ratio of SiO2 : CaO : P2O5 of 55 : 40 : 5, did not affect the growth of the encapsulated cells. If silica, biosilica, or polyP …

Temperature and polymer crosslinking degree influence on drug transfer from alpha,beta-polyasparthydrazide hydrogel to model membranes. A calorimetri…

1998

Abstract A non-steroidal anti-inflammatory drug, diflunisal, has been chosen as drug model to be incorporated in α , β -polyasparthydrazide (PAHy) matrices to study the effect of polymer crosslinking degrees on the release processes from hydrogel ( X =0.4 and X =0.8) to a model membrane represented by unilamellar vesicles of dipalmitoylphosphatidylcholine. The technique employed to monitor these processes was differential scanning calorimetry that appears to be particularly suitable to follow the transfer kinetics of a drug from a controlled release system to void biomembrane model. The drug release from the two PAHy hydrogels differently crosslinked by glutaraldehyde to the lipidic model w…