Investigation of the swelling behavior of crosslinked hyaluronic acid films and hydrogels produced using homogeneous reactions

Abstract

Hyaluronic acid (HA) has been crosslinked in solution with glutaraldehyde (GTA), 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC), poly(ethylene glycol) diglycidylether (EX 810), and divinyl sulfone (DVS) to form hydrogels. Flory-Rehner calculations were used to determine molecular weight between crosslinks (M c ), the crosslink density (V e ), and mesh size (e) of crosslinked hydrogels after 24-h swelling in distilled water. Generally, lower molecular weight films gave rise to decreased molecular weights between crosslinks as well as increased effective crosslink densities and decreased mesh size. The effects of pH and salt concentration were evaluated. Use of lower molecular weight HA gave rise to decreased molecular weights between crosslinks as well as increased effective crosslink densities and decreased mesh size. Water diffusion coefficients were measured for DVS and GTA hydrogels and were found to be 1.4 3 10 210 and 1.8 3 10 210 m 2 s 21 . Autocrosslinked and HA polyethyleneimine gels were also produced but had very limited stabilities compared with the covalently crosslinked materials.

Coating typologies and constrained swelling of hyaluronic acid gels within scaffold pores

“…The purpose of the present work was to address the problems faced to produce the coating typologies just described, and to characterize their physicochemical state in the scaffold-coating construct. More specifically, answers were sought to questions such as: what is the adequate procedure to uniformly introduce an aqueous gel into a hydrophobic structure; what is the influence of solution concentration and of adsorption time on the type of coating obtained; how does the swelling capacity of the gel change as a consequence both of its typology (in the sense discussed above) and of its being constrained by the scaffold's elasticity; how does the system's porosity change with coating, how does porosity change when the gel swells inside the pores; and, finally, to what extent can the adsorbed HA be crosslinked in order to broaden its potential applications [12,[24][25][26][27][28], i.e., to prevent its rapid dissolution, to regulate its chemical stability, swelling, degradation and consequently its drugs release properties.…”

Chemically Modified Natural Polysaccharides to Form Gels

“…Vinyl sulfone can also react with alcohols at high pH. This reaction has been done with hyaluronic acid to form hydrogels (Collins and Birkinshaw 2008). This vinyl-sulfone-linked hyaluronic acid has been investigated for drug delivery as well as for use as biocompatible coatings and tissue scaffolds.…”

“…In this case, the amine serves as the nucleophile. Additionally, alcohol units can be used as the nucleophile in reactions, for example, between poly(ethylene glycol) diglycidyl ether and hyaluronic acid (Collins and Birkinshaw 2008). In general, the amine group is a much more suitable nucleophile for this and other reactions.…”

A Microfluidic Platform to design crosslinked Hyaluronic Acid Nanoparticles (cHANPs) for enhanced MRI

“…In the literature studies, the chemical reaction between HA and DVS is performed at high pH values (0.2 M NaOH, 0.1 M NaCl, pH > 13)596061. In our microfluidic system, a study on the reagents was conducted to create, at the nozzle section, sulfonyl bis-ethyl linkages between the hydroxyl groups of the polymer chains forming nanoparticles (Fig.…”