Thermo-Responsive Poly(N-Isopropylacrylamide)-Cellulose Nanocrystals Hybrid Hydrogels for Wound Dressing.

Katarzyna Zubik,Yinan Wang,Pratyawadee Singhsa,Ravin Narain,Hathaikarn Manuspiya

doi:10.3390/polym9040119

Katarzyna Zubik, Yinan Wang + Show 3 more

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https://doi.org/10.3390/polym9040119

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Journal: Polymers	Publication Date: Mar 24, 2017
Citations: 131	License type: CC BY 4.0

Affiliation: Petromat, Chulalongkorn University

Abstract

Thermo-responsive hydrogels containing poly(N-isopropylacrylamide) (PNIPAAm), reinforced both with covalent and non-covalent interactions with cellulose nanocrystals (CNC), were synthesized via free-radical polymerization in the absence of any additional cross-linkers. The properties of PNIPAAm-CNC hybrid hydrogels were dependent on the amounts of incorporated CNC. The thermal stability of the hydrogels decreased with increasing CNC content. The rheological measurement indicated that the elastic and viscous moduli of hydrogels increased with the higher amounts of CNC addition, representing stronger mechanical properties of the hydrogels. Moreover, the hydrogel injection also supported the hypothesis that CNC reinforced the hydrogels; the increased CNC content exhibited higher structural integrity upon injection. The PNIPAAm-CNC hybrid hydrogels exhibited clear thermo-responsive behavior; the volume phase transition temperature (VPTT) was in the range of 36 to 39 °C, which is close to normal human body temperature. For wound dressing purposes, metronidazole, an antibiotic and antiprotozoal often used for skin infections, was used as a target drug to study drug-loading and the release properties of the hydrogels. The hydrogels showed a good drug-loading capacity at room temperature and a burst drug release, which was followed by slow and sustained release at 37 °C. These results suggested that newly developed drugs containing injectable hydrogels are promising materials for wound dressing.

Highlights

Hydrogels are soft and viscoelastic polymeric materials that can retain large amounts of water or biological fluids in their three-dimensional network structure [1,2,3]
There are several approaches that have been employed in attempts to improve the mechanical properties of hydrogels, including double network (DN) hydrogels [13,14], click hydrogels [15], topological (TP) hydrogels [16], macromolecular microsphere composite (MMC) hydrogels [17], and nanocomposite gels [18,19,20,21,22]
PNIPAAm-cellulose nanocrystals (CNC) hybrid hydrogels were synthesized by free-radical polymerization

Summary

Introduction

Hydrogels are soft and viscoelastic polymeric materials that can retain large amounts of water or biological fluids in their three-dimensional network structure [1,2,3] These materials can be designed to undergo reversible volume phase transition in response to environmental changes or external stimuli [4,5]. Due to these unique properties, together with the ability to simulate many physical properties of living tissues and the potential to be biocompatible, hydrogels have been of great interest for various biomedical applications such as drug delivery systems, contact lenses, wound dressing, scaffolds for tissue engineering, and cell encapsulation [6,7,8,9]. The major issue associated with the use of these nanoparticles in vivo is their potential toxicity [24,31]

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