Biological Properties of Chitosan Films with Different Degree of Deacetylation

Chitin and chitosan films were prepared by solution casting method. Chitosan specimens used in this study were deacetylated by 50.4%, 69.2%, 85.5% and 96.3%. Their water content, protein adhesion ability, cytocompatibility, cell adhesion ability, in vitro and vivo degradability and biocompatibility were evaluated. Results indicated that with the degree of deacetylation （DD） between 50% and 70%, the chitosan showed higher water content. The higher the DD, the stronger protein adhesion ability the chitosan had. All the films have good cytocompatibility and the films with higher DD have better cell adhesion ability. Chitin films degraded more rapidly than others, which disappeared in 2 to 4 weeks after they were implanted in subcutaneous tissue and musculature. Their inflammatory reaction became weaker as the films degraded. As the DD got higher, the films degraded slower. The films of DD 85.5% and DD 90.3% even didn＇t disappeared in 12 weeks after they were implanted. Their inflammatory reaction was mild at the beginning of degradation, and became severe in 4 to 8 weeks, then weaken at last. This basic result can be very helpful for tissue engineering.

Extraction and Characterization of Litopenaeus vannamei’s Shell as Potential Sources of Chitosan Biopolymers

Chitin is the second most abundant polysaccharide,produced mainly as an industrial waste stream during crustacean processing.Chitin can be derived into chitosan through the deacetylation process.Conversion of shrimp waste into chitosan via the deacetylation process could be considered a practical approach for shell waste remediation.In this study,chitosan’s physicochemical characteristics extracted from two types of Pacific white leg shrimp,L.vannamei’s shell(i.e.,rough and smooth),were compared with commercial chitosan.The yield,moisture,ash,solubility,water and fat binding capacity were measured.The degree of deacetylation(DDA)was calculated using FTIR,and their chemical Structure was confirmed using XRD and SEM-EDS.Both extracted chitosan showed no significant difference in yield,moisture,ash,solubility and water binding capacity but showed a significant difference with commercial chitosan.Moreover,the fat binding capacity of commercial chitosan showed the lowest percentage(408.34±0.83%)as compared to extracted chitosan(smooth shell 549.59±12.48%;rough shell 500.55±12.10%).The DDA indicated that extracted chitosan from the smooth and rough shell was considered good chitosan as compared to commercial chitosan with 84.08±1.27%,80.78±0.79%and 74.99±1.48%,respectively.Additionally,the presence of hydroxyl and amino groups from FTIR and a good crystallinity index was recorded using XRD of extracted chitosan.Based on observed characteristics,shrimp shell waste from L.vannamei can achieve chitosan standard quality as a biopolymer and highly potential to be applied in various industrial applications.

Bone remodeling effect of a chitosan and calcium phosphate-based composite

Chitosan is a biocompatible polymer that has been widely studied for tissue engineering purposes.The aim of this research was to assess bone regenerative properties of an injectable chitosan and calcium phosphate-based composite and identify optimal degree of deacetylation(%DDA)of the chitosan polymer.Drill holes were generated on the left side of a mandible in Sprague-Dawley rats,and the hole was either left empty or filled with the implant.The animals were sacrificed at several time points after surgery(7–22 days)and bone was investigated using micro-CT and histology.No significant new bone formation was observed in the implants themselves at any time points.However,substantial new bone formation was observed in the rat mandible further away from the drill hole.Morphological changes indicating bone formation were found in specimens explanted on Day 7 in animals that received implant.Similar bone formation pattern was seen in control animals with an empty drill hole at later time points but not to the same extent.A second experiment was performed to examine if the%DDA of the chitosan polymer influenced the bone remodeling response.The results suggest that chitosan polymers with%DDA between 50 and 70%enhance the natural bone remodeling mechanism.