Tehran University of Medical Sciences Journal of Medical Bacteriology 2251-8649 5 3-4 2016 10 15 9 14 EN Nafise Sadat Majidi Biology Department, University of Isfahan, Isfahan, Iran. Giti Emtiazi Biology Department, University of Isfahan, Isfahan, Iran. Samaneh Shahrokh Esfahani Biology Department, University of Isfahan, Isfahan, Iran. 2017 01 25 2017 01 25 Background:   Chitosan is unbranched polysaccharide composed of D-glucosamine and N-acetyl-D-glucosamine. Chitosan, derived from shrimp shell, has broad antimicrobial properties against Gram-negative, Gram-positive bacteria and fungi.  Methods:  Chitosan was extracted from shrimp shell and studied for cell entrapment and anti-bacterial properties. The hydrogel chitosan was used as the beads for cell entrapment and chitosan beads were designed to deliver cells and nutrients. These data confirmed with flow cytometric analyses.                  Results:   Experimental results exhibited that internal diffusion through the chitosan matrix was the main mechanism for whole gelation by TPP (Tri-polyphosphate). The minimum inhibitory concentration (MIC) for chitosan against Staphylococcus aureus and Escherichia coli was 16 and 32 μg/ml respectively. Conclusion:  Despite the antimicrobial properties of chitosan, trapped bacteria in the gel network were alive and were chelated indicating that their access to the outside was limited. https://jmb.tums.ac.ir/index.php/jmb/article/view/265 https://jmb.tums.ac.ir/index.php/jmb/article/download/265/192