Synthesis, fabrication, and biocompatibility of hexanoyl chitosan

Abstract

Hexanoyl chitosan (H- chitosan) was synthesized via a heterogeneous acylation reaction between chitosan powder and caproyl chloride. Successful substitution of hexanoyl side chains onto chitosan was confirmed by means of Fourier-transformed infrared spectrometry (FT-IR) and proton-nuclear magnetic resonance spectrometry (¹H-NMR). An elemental analysis result indicated the degree of substitution of hexanoyl groups per glucosamine unit of chitosan. Further biocompatibility evaluations of H- chitosan film comprised the cytotoxicity testing, and the attachment, proliferation, and spreading of L929 cells cultured on the surface of H- chitosan film were determined in vitro. Moreover, a H- chitosan non-woven mat composed of submicrofibers was successfully fabricated by electrospinning technique. The size and morphology of the as-spun fibers was dependent on several variables including solution concentration, applied electric potential, and salt addition as revealed by scanning electron microscope (SEM) images. The possible use of the electrospun mat as a tissue scaffold or a wound dressing material was further assessed in vitro. Non-toxicity of the electrospun mat was revealed by indirect cytotoxicity test with L929 cells. The electrospun mat was evaluated in terms of attachment and proliferation of human keratinocytes (HaCaT) and human foreskin fibroblasts (HFF) that were seeded and cultured on the scafflolds at different time points. In addition, the interactions of the cells cultured on the fibrous scafflolds with each other and with the surrounding fibers were investigated through SEM images.