Synthesis of N-alkylated chitosan and its interactions with blood.

When hydrophobically modified chitosan (HM-CHI) comes into contact with red blood cells (RBCs), it can cause agglomeration. This property leads HM-CHI to be a potential agent to form a rapid haemostatic plug to stop bleeding at wound sites. In this study, we investigated the properties of the HM-CHI biopolymer to act as an agent that rapidly clots blood. We have examined the synthesis and structural characteristics of HM-CHI - blood substances using X-ray diffraction, infrared spectroscopy and elemental analysis. To understand the rheological behaviour of RBCs within HM-CHI, we have studied the effects of HM-CHI on RBC aggregation and morphology using a rheometer and scanning electron microscopy (SEM), respectively. When mixed with sodium citrate, HM-CHI rapidly transformed human blood into an elastic gel. In contrast, un-modified chitosan (i.e. without hydrophobes) was unable to clot blood. The hydrophobias within HM-CHI entered into the RBC membranes and connected to the cells by a sample-spanning network, which subsequently led to the formation of an elastic gel. The gelling ability of HM-CHI is similar to that of fibrin-based sealants, but at a much lower cost and greater availability.