Search results for "hyaluronic acid."

Interpenetrated 3D porous scaffolds of silk fibroin with an amino and octadecyl functionalized hyaluronic acid

2015

An ethylenediamine (EDA) and octadecylamine (-C18) hyaluronic acid (HA) derivative, named HA-EDA-C18, has been used for the production of interpenetrated composite biomaterials with silk fibroin. The peculiar ionic strength sensibility of this HA derivative allows the production of porous matrices without the need for chemical crosslinking. Scaffolds have been produced through a salt leaching procedure by exploiting the properties of silk fibroin and HA-EDA-C18 to physically crosslink when forced through a syringe loaded with NaCl. The porosity of the sponges, comprised between 70-80%, was dependent on the amount of each polymer and NaCl size distribution. Moreover, through FT-IR analysis, …

Injectable in situ forming hydrogels based on natural and synthetic polymers for potential application in cartilage repair

2015

In this work we prepared two new hyaluronic acid (HA) based in situ forming hydrogels for the potential treatment of articular cartilage damages. In particular the amino derivative of HA (HA-EDA) and its graft copolymer with α-elastin (HA-EDA-g-α-elastin) were crosslinked, in mild physiological conditions via Michael-type addition, with α,β-poly(N-2-hydroxyethyl)-dl-aspartamide (PHEA) derivatized with divinylsulfone (DV). The swelling and degradation profile of the obtained hydrogels as well as the metabolic activity of incorporated bovine articular chondrocytes were investigated. Histological analysis and scanning electron microscopy (SEM) were performed to analyze the morphology of cells …

In situ forming hydrogels of new amino hyaluronic acid/benzoyl-cysteine derivatives as potential scaffolds for cartilage regeneration

2012

A new chemical strategy is described to link ethylenediamino (EDA) groups to primary hydroxyl groups of hyaluronic acid (HA) and the obtained derivatives have been characterized by 1H-NMR and 13C-NMR analyses. Such HA–EDA derivatives have been exploited to control the functionalization degree in benzoyl-cysteine (BC) groups, chosen as moieties able to allow both self-assembling in aqueous media and an oxidative crosslinking. In particular, the kinetics of oxidation of thiol groups in HA–EDA–BC derivatives has been studied in Dulbecco's Phosphate Buffer Solution (DPBS) pH 7.4 by colorimetric assays and rheological measurements. Mechanical properties of chemical hydrogels obtained after oxida…

Mechanical Characterization of Polysaccharide/polyaminoacid Hydrogels as Potential Scaffolds for Tissue Regeneration

2011

The mechanical properties of hydrogel scaffolds based on hyaluronic acid (HA) that were chemically crosslinked with α,β-poly(N-2-hydroxyethyl)(2-aminoethylcarbamate)-D,L-aspartamide (PHEA-EDA) were investigated. Variation of these properties as a function of three different PHEA-EDA amounts used to crosslink HA has been related to the reaction efficiency evaluated using a colorimetric assay. Moreover, the amount of unreacted amino groups that was still present in the hydrogels was related to the attachment behavior of human dermal fibroblasts to the hydrogel surface. The mechanical data and biological results suggest the suitability of the investigated hydrogels as scaffolds for the regener…

Preparation and characterization of new hydrogels based on hyaluronic acid and α,β-polyaspartylhydrazide

2007

Abstract Hyaluronic acid (HA) has been crosslinked with α,β-polyaspartylhydrazide (PAHy). The crosslinking reaction has been performed in acidic medium in the presence of various amounts of N-ethyl-N′-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC). All obtained samples have been characterized by FT-IR analysis and swelling measurements in double distilled water that have confirmed the occurrence of a chemical linkage between two polymers and the affinity towards aqueous medium of HA–PAHy networks, respectively. In vitro degradation assays have been performed in simulated physiological conditions as well as in the presence of hyaluronidase. Experimental data evidenced that HA–PAHy …

“Click” on PLGA-PEG and hyaluronic acid: Gaining access to anti-leishmanial pentamidine bioconjugates

2017

Pentamidine (Pent), an antiparasitic drug used for the treatment of visceral leishmaniasis, has been modified with terminal azide groups and conjugated to two different polymer backbones (PLGA-PEG [PP] copolymer and hyaluronic acid [HA]) armed with alkyne end-groups. The conjugation has been performed by Copper Catalyzed Azido Alkyne Cycloaddition (CuAAC) using CuSO4 /sodium ascorbate as metal source. The novel PP-Pent and HA-Pent bioconjugates are proposed, respectively, as non-targeted and targeted drug delivery systems against Leishmania infections. Moreover, Pent has been encapsulated into PP nanoparticles by the oil-in-water emulsion method, with the aim to compare the biological activ…

Hyaluronic Acid-g-Copolymers: Synthesis, Properties, and Applications

2013

The aim of this chapter is to review hyaluronic acid (HA) graft copolymers focusing in the description of chemical strategies employed for their synthesis, characterization procedures, and applications in biomedical and pharmaceutical field. Usually biocompatible synthetic polymers and peptides with therapeutic activity are grafted to HA to modify in appropriate way the physicochemical properties of the starting polysaccharide for a specific purpose and at the same time to exploit its biological role, biocompatibility, and targeting ability toward cells with receptors for HA. The use of such HA graft copolymers in the production of nanocarriers or hydrogels for modified drug release and sca…

MULTIFUNCTIONAL HYALURONIC ACID DERIVATIVE FOR EASY SCAFFOLD PROCESSING AND BIOLOGICAL FUNCTIONALIZATION

2015

"Click" on PLGA-PEG and hyaluronic acid: gaining access to anti-leishmanial pentamidine bioconjugates

2018

Pentamidine (Pent), an antiparasitic drug used for the treatment of visceral leishmaniasis, has been modified with terminal azide groups and conjugated to two different polymer backbones (PLGA-PEG [PP] copolymer and hyaluronic acid [HA]) armed with alkyne end-groups. The conjugation has been performed by Copper Catalyzed Azido Alkyne Cycloaddition (CuAAC) using CuSO4/sodium ascorbate as metal source. The novel PP-Pent and HA-Pent bioconjugates are proposed, respectively, as non-targeted and targeted drug delivery systems against Leishmania infections. Moreover, Pent has been encapsulated into PP nanoparticles by the oil-in-water emulsion method, with the aim to compare the biological activi…

Inhibition of TSH/IGF-1 Receptor Crosstalk by Teprotumumab as a Treatment Modality of Thyroid Eye Disease

2021

Abstract Context We previously presented evidence that TSH receptor (TSHR)-stimulating autoantibodies (TSAbs) bind to and activate TSHRs but do not bind to IGF1 receptors (IGF1Rs). Nevertheless, we showed that IGF1Rs were involved in thyroid eye disease (TED) pathogenesis because TSAbs activated crosstalk between TSHR and IGF1R. Teprotumumab, originally generated to inhibit IGF1 binding to IGF1R, was recently approved for the treatment of TED (Tepezza). Objective To investigate the role of TSHR/IGF1R crosstalk in teprotumumab treatment of TED. Design We used orbital fibroblasts from patients with TED (TEDOFs) and measured stimulated hyaluronan (HA) secretion as a measure of orbital fibrobla…