Synthesis, characterization and properties of carboxymethyl kappa carrageenan

In order to develop a wound healing material possessing anticoagulant activity, antimicrobial activity and moisture absorbability and moisture-retention capacity, carboxymethyl κ-carrageenan (CMKC) was synthesized by the reaction of κ-carrageenan with monochloroacetic acid. The products were characterized by FT-IR, 13C NMR, degree of substitution (DS) and molecular weight. Anticoagulant activity of CMKC was investigated by APTT, TT and PT assays. The results showed that CMKC with a low DS promoted anticoagulant activity in comparison with κ-carrageenan, but as the DS further increased from 0.42 to 1.09, the activity decreased. Antibacterial activity was evaluated and we found that the introduction of carboxymethyl groups conferred antibacterial activity onto κ-carrageenan. Results indicated that CMKC exhibited good antimicrobial properties against Escherichia coli and Staphylococcus aureus, and the antibacterial activity of CMKC enhanced as the DS increased. CMKC displayed better moisture-absorption and water-retention ability than κ-carrageenan and as the DS increased, these properties of CMKC increased.