An investigation of chitosan and its derivatives on red blood cell agglutination†
6-Deoxy-6-(2-aminoethyl) amino chitosan (CS-AEA) and aminoethyl modified CS-AEA (CS-AEA-AEM) were synthesized and characterized using FTIR, NMR and elemental analysis. The results showed that the expected CS derivatives were obtained, and the amine group content increased successively in CS, CS-AEA and CS-AEA-AEM. The red blood cell (RBC) agglutination behaviors in solutions of CS and its derivatives were studied using optical microscopy (OM) and ultraviolet-visible (UV-Vis) spectrophotometry. The results demonstrated that the agglutination of RBCs became more evident upon decreasing the pH value and increasing the concentration. Although CS-AEA-AEM had the highest content of amine groups, CS-AEA exhibited the best agglutination performance under the pH and concentration range studied. Potentiometric titration and ionization degree calculations showed that the agglutination behavior of RBCs was determined by the number of protonated amines in CS or its derivatives. Hemocompatibility tests showed that the hemolysis of CS derivatives increased after modification, and the CS derivatives could be classified as a slightly hemolytic material. We have sucessfully developed a CS derivative (CS-AEA) with very good RBC agglutination performance under neutral conditions.