Alginate-Chitosan-Alginate Ion Replacement Gels

Alginate-Chitosan-Alginate (ACA) ion replacement gels were initiated and defined in this paper, which was a novel ion exchange system with capsular structure composed of capsular membrane of alginate-chitosan polyelectrolyte complex and intracapsular alginate solution. Being different from traditional ion exchange resin, the ion exchange process of ACA was sol-gel phase transformation, which was a novel ion adsorbent. Ion replacement properties, mechanism and structure of ACA were studied in details. ACA with high strength and stability were prepared through modification of microencapsulated materials and optimization of preparation conditions. The adsorption of ACA for Pb2+ had quicker adsorption velocity, high selectivity and high enrichment capacity, which were contributed to be a novel blood adsorbent. In addition, ACA had smooth surface and high biological compatibility, which was hopeful as a blood adsorbent in order to cure metal toxicosis.A series of novel microspheres and microcapsules of natural polymers, alginate ion crosslinking gel microspheres, alginate/IPDI gel microspheres, microencapsulated ion exchange solution and carboxymethyl chitosan-chitosan- carboxymethyl chitosan microcapsule were developed, which all were not reported yet. The structure and ion adsorbent properties were studied. The results revealed these novel ion adsorbents had excellent ion adsorbent properties and can be used in many fields. Carboxymethyl chitosan-chitosan-carboxymethyl chitosan microcapsule with complete chitosan matrix can be used in biological immobilization, drug control release and so on.In this paper, gel microspheres of calcium alginate were prepared through electrostatic droplet generator. The mechanism of droplet formation, the shape and particle sizes of microspheres were investigated. The formula of theoretical calculation of diameter of gel microspheres is accordingly given in different conditions. The experimental results match the theoretical calculation well. The formula of theoretical calculation can be widely applied to study the effect of physicochemical properties of alginate and parameters of electrostatic droplet generator on diameter of gel microspheres of calcium alginate.The X-ray photoelectron spectroscopy (XPS) and IR spectra were used to investigate metal alginate complexes. The analytical methods were systematically established, which was very helpful to study coordination of metal polymers, especially metal polysaccharide. The coordination and stability between metal ions and alginate were given, which consisted with adsorption selectivity of alginate for metal ions.