Preparation And Characteristics Of Chitosan-Based Medical Sponges

Medical Sponge Scaffold (MSS) is a sort of solid scaffold containing myriad air-free pores. MSS utilized as drug releasing carrier, wound dressing and tissue engineeing scaffold has been received increasing attentions in the fields of pharmaceutics and biomedicine. In this paper, the materials including artificial and natural polymers to construct sponge, the methods used to prepare MSS, the current progress, application and tendency of MSS are sumerized systematically. The effects of the proportion of constituents in the sponge and the preparation methods on sponge properties such as water uptake ability, water retention ability, drug release ability and in vitro & vivo degradability were discussed one by one.The main contents and conclusions of this paper are discussed as follows: Asymmetric PVA-Chitosan-Gelatin sponges were prepared by pre-freezing and then freeze-drying technique. The properties of PVA-Chitosan-Gelatin sponges, such as the water uptake ability, the water maintenance ability, drug release efficiency and degradable behavior, were studied. The sponges were composed of dense surface and porous layer. The results show that the water uptake ability, the water maintenance ability, drug release efficiency and degradable behavior are related to the proportion of components in the sponge. When the weight ratio of PVA:Chitosan:Gelatin was 1:2:2, the best water uptake ability and water maintenance ability are obtained, the sponge can absorb water 3714% and maintain 40% of absorbed water after 180h. The introduction of PVA delays the drug release of the sponge and increases its resistance in vitro enzyme digestion.Acetylated chitosan-gelatin sponges were prepared, the influence of acetylation on structure and properties of chitosan-gelatin sponges was studied. Acetylated chitosan-gelatin sponges were produced by adding acetic anhydride into the mixture of chitosan and gelation solution and then freeze-drying the formed gel. Ciprofloxacin was used as a model drug to study the effect of antibacterial properties of sponges. The water uptake and water retention abilities of sponges first increased and then decreased as the chitosan content in the sponge increased. As the degree of acetylation of sponges increased the water uptake ability of sponges was first decreased and then increased, while the order of water retention ability of sponges was the opposite. The rate of weight loss of sponges in enzyme solution was not influenced by the chitosan content in the sponge, but enhanced as the degree of acetylation of sponges increased. The effect of antibacterial of drug-loading sponges depended on the chitosan content in the sponge.Chitosan-Alginate sponges were prepared by freeze-drying and self-assembly technique. The effects of chitosan molecular weight on sponge properties, such as the water uptake ability, the water maintenance ability, drug release efficiency and sponge stuctures were studied. The experiment results indicate that the water uptake ability, the water maintenance ability, drug release efficiency and sponge stuctures are related to the chitosan molecular weight in the sponge. With the increase of chitosan molecular weight, the quantity of CS absorbed in the sponge, water uptake ability and water maintenance ability of the sponge increased.