Role of Chitosan on Some Physical Properties and the Urea Controlled Release of the Silk Fibroin/Gelatin Hydrogel

Abstract

Natural polymers are widely used as biodegradable matrices for the controlled release technology because they can improve the performance of the materials and make them environmentally friendly. In this work, the silk fibroin (SF)/gelatin hydrogel with chitosan (CS) was prepared by solvent casting aiming to reduce the rate of urea release from the hydrogels. Results from the Fourier transform infrared confirmed that no intermolecular interactions had taken place after the addition of CS into the SF/ gelatin. Furthermore, the increase of CS content in the SF/ gelatin blended hydrogels caused the decrease in their porosity that affected the increase in their crystallinity, degree of swelling, water solubility, and surface hydrophobicity. The rate of urea release from the hydrogels also depended on the content of CS of which its value of diffusion exponent characteristics (n) determined from the Korsmeyer-Peppas model for SF/gelatin/CS hydrogels were greater than 1.0. This indicated that the urea release from the SF/gelatin hydrogels with CS was a super case II transport type. Moreover, the urea release rate (k) of the SF/gelatin/CS hydrogels was lower than that of the SF/ gelatin hydrogel itself indicating an extension of the urea release from the SF/gelatin hydrogels by CS which could be utilized for controlled release applications.

A Theoretical Multifractal Model for Assessing Urea Release from Chitosan Based Formulations

“…In view of modeling the urea release characteristics, eight formulations based on chitosan, salicylaldehyde and urea (Table 1) were prepared applying the procedure of the in situ hydrogelation described in the Experimental section. It should be remarked that the in situ procedure allowed for efficient encapsulation of a large amount of fertilizer [29][30][31][32]. The formulations were firstly investigated by scanning electron microscopy (SEM) measurements to observe the influence of both the crosslinking density and urea content on their morphology.…”

Chitin/Chitosan: Versatile Ecological, Industrial, and Biomedical Applications

“…Controlled release of urea by a variety of chitosan-based composites was established. Urea dispersed with humic substances in chitosan (Araújo et al 2017), urea encapsulated in chitosan-acryamide (Siafu 2017), urea release from adduct of silk fibroingelatin-chitosan hydrogels (Rattanamanee et al 2015), urea smectite clay chitosan composite (Puspita et al 2017), and urea-kaolinite mixed with chitosan (Roshanravan et al 2015) were tested for controlled release of the fertilizer.…”

Optimization of metal–organic (citric acid) frameworks for controlled release of nutrients

“…For instance, chitosan is only soluble in diluted acid, making it difficult to prepare water-soluble chitosan derivatives; otherwise, chitosan is dissolved in organic solvents, which not only increases the costs, but also causes serious environmental concerns. [15][16][17] Starch exhibits a poor water resistance and lm-forming ability, and is easily degraded in soil. 18,19 Lignin has complex components, making its fabrication difficult.…”