Chitosan functionalization in water : a novel approach to develop a chitosan-allergen delivery system

Abstract

A water soluble chitosan derivative prepared by functionalizing chitosan with poly(ethylene glycol) monomethyl ether (mPEG) and cholic acid (CA) in a water-ethanol system for the use as allergen delivery system is proposed. The derivative is water soluble depending on the molecular weight of chitosan and mPEG and the ratios of chitosan:mPEG:CA. The structural analyses by Fourier transform infrared spectroscopy (FTIR) and 1H nuclear magnetic resonance spectroscopy (1H NMR) confirm the conjugation of mPEG and CA with substitution degree to be about 20-30%. The derivative performs nanospherical shape with size 40 nm whereas the incorporation of a model allergen, the house dust mite, by mixing the aqueous solutions of the derivative and the house dust mite initiates larger nanosphere size to be 200 nm as observed by transmission electron microscope (TME). A preliminary in vitro immune response test based on lymphocyte transformation shows that the lymphocytes cultured in CS-mPEG-CA incorporated with allergen have less proliferation than the one in allergen as observed from microscope.