A Spectroscopic Study of Solid-Phase Chitosan/Cyclodextrin-Based Electrospun Fibers

Chen Xue,Lee D Wilson

doi:10.3390/fib7050048

Abstract

In this study, chitosan (chi)/hydroxypropyl-β-cyclodextrin (HPCD) 2:20 and 2:50 Chi:HPCD fibers were assembled via an electrospinning process that contained a mixture of chitosan and HPCD with trifluoroacetic acid (TFA) as a solvent. Complementary thermal analysis (thermal gravimetric analysis (TGA)/differential scanning calorimetry (DSC)) and spectroscopic methods (Raman/IR/NMR) were used to evaluate the structure and composition of the fiber assemblies. This study highlights the multifunctional role of TFA as a solvent, proton donor and electrostatically bound pendant group to chitosan, where the formation of a ternary complex occurs via supramolecular host–guest interactions. This work contributes further insight on the formation and stability of such ternary (chitosan + HPCD + solvent) electrospun fibers and their potential utility as “smart” fiber coatings for advanced applications.

Highlights

Chitosan is a copolymer containing β-(1-4)-linked N-acetyl-D-glucosamine and D-glucosamine monomer units derived from the deacetylation of chitin, where the degree of acetylation depends on the extent of hydrolysis [1,2,3,4,5,6,7]
It was noted that the Chi:hydroxypropyl β-cyclodextrin (HPCD) 2:50 fiber contained less nodule-shape elements and had a large fiber diameter when compared with the Chi:HPCD 2:20 fiber
Chi:HPCD 2:20 and 2:50 fiber were produced via electrospinning of a mixture of HPCD and chitosan using trifluoroacetic acid (TFA) as a solvent

Summary

Introduction

Chitosan is a copolymer containing β-(1-4)-linked N-acetyl-D-glucosamine and D-glucosamine monomer units derived from the deacetylation of chitin, where the degree of acetylation depends on the extent of hydrolysis [1,2,3,4,5,6,7]. The amino polysaccharide units of chitosan contribute to its biodegradability and biocompatibility, along with its unique physicochemical properties relevant to adsorption. According to the degree of ionization of glucosamine groups of chitosan, the antimicrobial and adsorption properties can be altered by variable pH levels [8,9,10,11]. To attain additional performance in these applications, research has focused on the design of different morphological forms of chitosan that include nanofibrous systems, owing to the high surface area of these biomaterials [2,3,4,14,16,17,18,19,20]. Burns et al reported the use of trifluoroacetic acid (TFA) and hydroxypropyl β-cyclodextrin (HPCD) as additives to assist in the electrospinning of chitosan nanofibers [31]. The potential of HPCD to form noncovalent host–guest complexes with various molecular species, in conjunction with the polyelectrolyte nature of chitosan, may further enhance the utility of such nanofibrous materials as advanced coating materials [31,32]

Methods

Results

Conclusion