Preparation And Characterization Of Chitosan Derivatives Bio-materials With Iodine

The combination of chitosan(CTS) and iodine not only has the good biocompatibility of chitosan, but also has an efficient sterilization of iodine. The CTS and iodine molecules are combined with intermolecular forces, and the CS had only small adsorbing ability of iodine from the studies, the CTS-iodine adducts obtained is instability. Therefore, how to enhance the adsorbing ability of iodine is the key points to obtained stable CTS-iodine adducts.In this paper, the CTS was modified by positioning grafted the functional groups on the-NH2 position of CTS through the method of ―amino protection-graft-deprotection‖, like thiosemicarbazide, benzyl isothiocyanate(BI), propionyloxy, which containing oxygen, sulfur, and benzene ring, this functional groups could increase the adsorption capacity of iodine molecules relying on the lone pair of electrons electrostatic interaction of oxygen and sulfur, and the dispersion force of benzene ring. And the hydroxypropyl was also positioning grafted on the-OH position of CTS to increase its hydrophilic, the CTS derivatives of 2-N- benzoyl thiourea hydroxypropyl chitosan-6-O-(BTH-HPCTS), 2-Nthiosemicarbazide hydroxypropyl chitosan-6-O-(ATU-HPCTS) and 2-N- propionic acid-6-O- hydroxypropyl chitosan(HP-PCTS) were prepared. Finally, the different modified CTS derivatives were made into the corresponding CTS derivatives film and sponge with iodine, and the physical & chemical properties, the release properties of iodine and the antibacterial properties were investigated. The main contents are as follows:(1)The CTS derivatives of BTH-HPCTS, ATU-HPCTS and HP-PCTS were prepared by grafting different molar ratios of thiosemicarbazide, benzyl isothiocyanate, propionic acid group, and then been hydroxylation. The CTS derivatives were characterized by infrared(IR), ultraviolet(UV), X-ray diffraction(XRD) and solubility test, the results showed that: the CTS derivatives all appeared the characteristic absorption peak of-CH3 at 2970 cm-1, indicated the successful grafting of hydroxypropyl, and the characteristic absorption peaks occurring at 1637 cm-1, 1263 cm-1, 1600 cm-1, respectively, validated the thiosemicarbazide, benzyl isothiocyanates and propionic acid groups were grafted successfully. At the same time, the results of powder XRD and UV reflectance consistent with the conclusion.(2)The CTS derivatives gel films were prepared by CTS derivatives mixed with the polyvinylpyrrolidone(PVP), gelatin as a thickener, and the BTH-HPCTS, ATU-HPCTS and HP-PCTS films with iodine were obtained with CTS derivatives gel films added iodine in ethanol. By contrast the IR, XRD, scanning electron microscopy(SEM), thermal stability analysis(TG) results of CTS derivatives gel films and CTS derivatives gel films with iodine, all the results indicated the iodine have a certain impact on the molecular structure, crystallinity and space structures of the CTS derivatives, the UV results showed that the derivatives has a good absorption of between 200 and 600 nm. The iodine content, iodine released results confirmed the polymer has a good adsorption of iodine after the CTS grafted the thiosemicarbazide, benzyl isothiocyanate and propionic acid, and also have the effect of slow controlled release of iodine, there was still no downward trend at 120 min, the antimicrobial study demonstrated that the inhibition zone diameter of CTS derivatives film with iodine against Staphylococcus aureus and Escherichia coli were all more than 15 mm, are highly sensitive, with a good antibacterial effect.(3)The CTS derivatives sponge were prepared by CTS derivatives with polyvinyl alcohol cross-linked by glutaraldehyde, foamed and cured, plasticized with sulfuric acid, with 2-acrylamido-2-methylpropane sulfonic acid(AMPS) to increase the absorption of water, poly glycol(PEG) to soften the sponge, and BTH-HPCTS, ATU-HPCTS and HP-PCTS sponge with iodine were obtained with CTS derivatives sponge and iodine in ethanol. The CTS derivatives sponge with iodine were characterized by TG, SEM, the release effect of iodine, mechanical strength, bactericidal effect and other indicators. The results of water absorption and water retention both showed a significantly improvement after absorbed of iodine, and the elongation at break of BTH-HPCTS, ATU-HPCTS and HP-HPCTS sponge with iodine sponge all have increased, and the elongation at break increases with increasing amounts of iodine in ethanol. The oxygen permeability of sponge with iodine increased with the increasing iodine content. The results of iodine release of sponge with iodine showed the effect of slow controlled release, the release reached equilibrium when it was 80 min, there was still no downward trend at 120 min. The inhibition zone diameter of CTS derivatives sponge with iodine have a significant inhibitory effect against Staphylococcus aureus and Escherichia coli, has the great potential as sterilization of medical materials, and the inhibitory effect of BTH-HPCTS and ATU-HPCTS sponge with iodine were better than HP-HPCTS sponge with iodine.The CTS derivatives dressings with iodine prepared by different modified CTS has a good adsorption effect of iodine, also the slow release effect of iodine and a long time efficacy of antibacterial effect. The CTS derivatives dressings with iodine not only have the function of anti-inflammatory and tissue repair of CTS, but also have the bactericidal efficiency of iodine, the double effects provided an ideal healing environment for wound surface.