Dual Properties of the Deacetylated Sites in Chitosan for Molecular Immobilization and Biofunctional Effects

Abstract

Polypropylene nonwoven fabric was surface-activated by high-density oxygen microwave plasma, followed by graft copolymerization with acrylic acid (AAc) and then coupling with chitosan molecules. The pAAc-grafted surface containing C=O in carboxylic acid exhibited a hydrophilic character capable of promoting water absorbency. A larger portion of minimum 85% deacetylated sites in chitosan molecules was then coupled with the grafted pAAc (around 149 microg.cm(-2)) by forming amide bonds at their interface. The covalently bonded chitosan was weighted around 44 microg.cm(-2). The smaller portion of the deacetylated sites demonstrated a distinctive structure as polycations, i.e., NH(3)(+), on the immobilized chitosan. The respective structures following sequential reactions were identified using Fourier transform infrared-attenuated total reflection and X-ray photoelectron spectroscopy with peaks deconvolution. The NH(3)(+) sites on the immobilized chitosan exhibited biofunctional in anticoagulation and in antibacterial property. Blood cells agglutination or agglomeration upon the chitosan-immobilized surface, in particular for red blood cells and platelets, resulted from hydrophilic effect derived from the grafted pAAc and the chitosan itself, and ionic attractions between polycations and blood cells. In addition, the agglutinated cells retained their original morphologies. It is therefore very promising to apply this durable chitosan-immobilized surface for making an antibacterial support, at the same time, for retaining blood cell affinity.

Chitosan immobilization to the polypropylene nonwoven after activation in atmospheric – pressure nitrogen plasma

“…Absorption bands at 1650 cm -1 and 1554 cm -1 indicate the amides I (C=O in O=C-NH) and amides II (-NH in O=C-NH), respectively. In pure chitosan amide I were determined at 1653 cm -1 and amide II at 1595 cm -1 [6]. The shifting of amide II (-NH in O=C-NH) toward right may be due to the formation of new amide bonds between amine groups of chitosan and carboxylic group on the plasma activated surfaces, which has been supported by the results of XPS analysis.…”

“…In the first step, the hydrophobic polypropylene surface is functionalized mostly by grafting with carboxylic acids, preferably acrylic acids, and in the second step the chitosan molecules are coupled with carboxylic groups by forming amide covalent bonds at their interface [5,6]. Liao [6] studied the dual properties of amino groups in chitosan for molecular immobilization and bio functional effects. They activated polypropylene nonwoven fabric by high density oxygen microwave plasma, followed by graft copolymerization with acrylic acid and then coupling with chitosan molecules.…”

“…Liao continued in his investigation of polypropylene surface grafting with chitosan and some new additional results are summarized in [6]. In this study he used the same grafting procedure as it was described in his previous paper.…”

The Effect of Different Solvents for Chitosan Solubilization on The Crystal Growth of in situ Prepared Hydroxyapatite

“…The peak at high binding energy in the range of 288.3 to 289.4 eV are related to the carboxylic acid groups of AA and Ac acids which showed larger area in the case of acetic acid, probably due to the strong association between the protonated amine groups of CS and the ionized carboxylate of acrylic acid. Finally, new small spectral component at low binding energy 282.5 eV is assigned to some carbon with a differential charging effect (C*) observed in only acetic acid samples, this phenomenon is frequently observed in the ceramics [19,25].…”

Development of an Amperometric Hydrogen Peroxide Biosensor based on the Immobilization of Horseradish Peroxidase onto Nickel Ferrite Nanoparticle-Chitosan Composite

“…Much effort has been made to improve the performance of chitosan for application as biosensors. These adjustments include its structural modification, change in molecular factors, as well as the incorporation of metal oxide nanoparticles in the chitosan network structure [24,25].…”