Chitin-Glucan Complex Hydrogels: Optimization of Gel Formation and Demonstration of Drug Loading and Release Ability.

Diana Araújo,Thomas Rodrigues,Filomena Freitas,Vítor D Alves

doi:10.3390/polym14040785

Diana Araújo, Thomas Rodrigues + Show 2 more

Open Access

https://doi.org/10.3390/polym14040785

Copy DOI

Journal: Polymers	Publication Date: Feb 17, 2022
Citations: 12	License type: CC BY 4.0

Affiliation: Universidade Nova de Lisboa, University of Lisbon

Abstract

Chitin-glucan complex (CGC) hydrogels were fabricated through a freeze–thaw procedure for biopolymer dissolution in NaOH 5 mol/L, followed by a dialysis step to promote gelation. Compared to a previously reported methodology that included four freeze–thaw cycles, reducing the number of cycles to one had no significant impact on the hydrogels’ formation, as well as reducing the total freezing time from 48 to 18 h. The optimized CGC hydrogels exhibited a high and nearly spontaneous swelling ratio (2528 ± 68%) and a water retention capacity of 55 ± 3%, after 2 h incubation in water, at 37 °C. Upon loading with caffeine as a model drug, an enhancement of the mechanical and rheological properties of the hydrogels was achieved. In particular, the compressive modulus was improved from 23.0 ± 0.89 to 120.0 ± 61.64 kPa and the storage modulus increased from 149.9 ± 9.8 to 315.0 ± 76.7 kPa. Although the release profile of caffeine was similar in PBS and NaCl 0.9% solutions, the release rate was influenced by the solutions’ pH and ionic strength, being faster in the NaCl solution. These results highlight the potential of CGC based hydrogels as promising structures to be used as drug delivery devices in biomedical applications.

Highlights

Hydrogels are three-dimensional network structures fabricated from synthetic or natural polymers capable of absorbing large amounts of water [1–3]
The hydrogels prepared by freezing during 48 h using 0, 1, 2, or 3 freeze–thaw cycles were identified as Na50, Na51, Na52, and Na53 hydrogels, respectively, while the hydrogel prepared by 1 freezing cycle of 18 h was coded as Na51 * hydrogel (Table 1)
The freeze–thaw procedure followed by dialysis, recently reported by Araújo et al [22], was used to dissolve Chitin-glucan complex (CGC) in NaOH 5 mol/L and prepare CGC hydrogels, which exhibited a dense and stiff gel structure

Summary

Introduction

Hydrogels are three-dimensional network structures fabricated from synthetic or natural polymers capable of absorbing large amounts of water [1–3]. Biopolymer hydrogels have attracted increasing interest due to their biocompatibility, biodegradability, environmentally friendly features, and tissue-mimicking consistency These valuable characteristics make them suitable materials for utilization in a wide range of applications from food and agriculture [4] to cosmetics [5] and biomedicine [6]. Chemical hydrogels are mostly connected through a covalently cross-linked network, in which the addition of crosslinking agents promotes the reaction between the functional groups of the polymer chains [7,8]. Those chemical agents are often toxic compounds, and their presence may have adverse effects, such as undesirable reactions with bioactive substances or affect the hydrogels’ biocompatibility [9]. Physically crosslinked hydrogels, especially biopolymer-based ones, are promising materials for use in the biomedical field due to the use of mild conditions during their fabrication, and the absence of organic solvents and toxic crosslinking agents [10,11]

Methods

Results

Conclusion