Chitosan Hydrogels Crosslinked by Genipin and Reinforced with Cellulose Nanocrystals: Production and Characterization

Cristiane Pereira De Siqueira,Rodrigo Sousa Silva,Thaís Larissa Do Amaral Montanheiro,Dayane Batista Tada,Ana Paula Lemes,Andréia Aparecida Do Nascimento Pomari

doi:10.3390/jcs3030084

Cristiane Pereira De Siqueira, Rodrigo Sousa Silva + Show 4 more

Open Access

https://doi.org/10.3390/jcs3030084

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Abstract

In this work, chitosan hydrogels crosslinked with genipin and reinforced with cellulose nanocrystals (CNC) were developed and characterized with the aim of future biomedical applications. CNC was produced by acid hydrolysis and characterized by atomic force microscopy (AFM). Chitosan/CNC nanocomposite hydrogels were produced with different CNC concentrations (w/w): 0%, 2%, 4%, and 6%. The genipin was used as a crosslinking agent in a genipin/chitosan molar proportion of 1:8. The hydrogels were characterized by porosity measurements, scanning electron microscopy (SEM), swelling test, and mechanical compression test. No significant differences were observed concerning the porosity of the hydrogels; however, a trend of decreasing porosity was observed with increasing CNC content. The SEM images showed a better pore structure as the CNC concentration increased. A decrease in the swelling degree with increasing CNC content in the chitosan/CNC nanocomposite hydrogel was verified in the swelling tests. An increase in the CNC concentration in the chitosan/CNC nanocomposite hydrogel caused a gradual increase in the maximum stress and maximum strain as observed in the compression tests, showing a significant difference between chitosan/CNC 6 wt % and neat chitosan hydrogel.

Highlights

The development of new biomaterials has been an essential tool to improve the treatment of various diseases, traumas, and other medical problems of several complexity degrees
In this work, the effect of cellulose nanocrystals (CNC) introduction on chitosan hydrogels crosslinked with genipin was evaluated, aiming towards the development of a biocompatible, biodegradable, and low-toxicity material with satisfactory mechanical properties for future biomedical applications
An increase of about 36% was obtained for the sample produced with 6 wt % of CNC compared to neat chitosan hydrogel

Summary

Introduction

The development of new biomaterials has been an essential tool to improve the treatment of various diseases, traumas, and other medical problems of several complexity degrees. Among the possible crosslinking agents, genipin has been widely studied due to its natural origin, low cytotoxicity, and great biocompatibility compared to other conventional crosslinkers [14] It presents in its chemical structure two reactive sites through which occur its connection with a polymer matrix, forming the three-dimensional polymer network. The low mechanical properties of chitosan hydrogel crosslinked with genipin hamper its application in cases where it is subjected to stress such as traction, compression, shear, and torsion For this reason, the introduction of reinforcing nanofillers into chitosan matrixes has been evaluated both in the production of engineering materials and in the production of biomaterials [5,6,15]. In this work, the effect of CNC introduction on chitosan hydrogels crosslinked with genipin was evaluated, aiming towards the development of a biocompatible, biodegradable, and low-toxicity material with satisfactory mechanical properties for future biomedical applications

Materials and Methods

Porosity

Swelling Tests

Findings

Conclusions