Rheological Study of Genipin Cross-Linked Chitosan Hydrogels

Abstract

This paper reports the rheological behavior of chitosan solutions that have been cross-linked with different amounts of genipin, at body temperature and physiological pH. The effect of the cross-linker loading on the rheological properties of hydrogels has been evaluated. The oscillatory time sweep method was used to monitor the dynamic viscoelastic parameters during in situ (i.e., in the rheometer) gelation experiments, enabling the determination of the gelation time. The stress and frequency sweeps were employed to measure G' of the cured hydrogels. It was found that the solutions of chitosan cross-linked with genipin, under physiological conditions, could form relatively strong elastic gels when compared to those of pure chitosan. Moreover, the gelation time obtained from the crossover of G'' and G' was in excellent agreement with the value obtained from the Winter-Chambon criterion. A significant reduction on this parameter was achieved even at low genipin concentrations. This behavior suggests that these formulations are able to be produced in situ and thus constitute promising matrices for cells and bioactive molecule encapsulations.

Effect of the preparation method on the drug loading of alginate-chitosan microspheres

“…In particular, there was a notable increase of 15% in the encapsulation efficiency of lisinopril when genipin was used instead of CaCl 2 in the hydrogel preparation through the aqueous method. As previously reported [19], controlled release rates of indomethacin from ALG-CHI particles were achieved by increasing the genipin content in the hydrogel due to a higher crosslinking density. In fact, the genipin content can be manipulated in order to control the chitosan crosslink density [20].…”

“…Calcium chloride is frequently used as an ionic crosslinker in ALG-CHI systems [7][8][9]11] causing a reduction in the hydrogel porosity [17]. Among the covalent crosslinkers, there are some reports for chitosan nanoparticles crosslinked with glutaraldeyde [13,18] and genipin [19,20]. Genipin is a natural covalent crosslinker that presents very low toxicity in comparison with conventional crosslinkers and can present promising results in the reinforcement of ALG-CHI based microspheres [20].…”

Enhanced dermal delivery of diflucortolone valerate using lecithin/chitosan nanoparticles: in-vitro and in-vivo evaluations

“…The storage (elastic) modulus (G′) and loss (viscous) modulus (G′) were measured for gel formulations. 31,32 The storage modulus as a function of frequency for chitosan hydrogels of varying nanoparticle concentrations are presented in Figure 5. Altering the concentration of nanoparticles dramatically changed the viscoelastic properties of the gel.…”

Influence du polyéthylène oxyde (PEO) de différentes masses moléculaires sur les propriétés rhéologiques des suspensions d’argile

“…Des résultats viscoélastiques identiques ont été obtenus par plusieurs auteurs (Clasen et Kulicke, 2001 ;Habas et al, 2008 ;Moura et al, 2007 ;Niedzwiedz et al, 2008 ;Coussot et Gossiord, 2001). On peut comprendre aisément l'origine d'un tel comportement rhéologique en remarquant que les chaînes macromoléculaires adjacentes forment des boucles d'enchevêtrement topologiques les unes avec les autres : pour les « faibles » fréquences.…”