Poly blood anticoagulant

Sulfated N-carboxymethyl chitosan was dissolved in acetate buffer (50 mg/ml), submitted to sonication, filtered on 0.45 ym Millipore membranes and submitted to chromatography on Bio-Gel P-100. Since it is known that the average molecular weight and poly-dispersity are important parameters to be taken into account when testing a blood anticoagulant, we have developed this approach in order to reduce the molecular weight of the sulfated N-carboxymethyl chitosan, which originally was over 1,000,000 dalton. 

By examining the polymeric materials which are currently used in cHnical application it can be seen that while their mechanical properties satisfy requirements, their total compatibility with blood has still not been achieved. Therefore, commercial polymers like polyurethanes, siHcones, polyolefins and poly(vinyl chloride) which are used as short-term implant materials show thrombogenic properties and require the introduction of anticoagulants [26,43]. 

The blood-material interactions were also investigated by a microsphere-column method (7,9,77). After human whole blood without an anticoagulant was passed through the columns packed with polymer-coated beads for 15 min and the column was rinsed with phosphate buffered solution(PBS), the color of the column with poly(BMA) turned red, that is, serious thrombus formation occurred in the poly(BMA) column. However, the poly(MPC-co-BMA) colunms were clear even when the MPC mole fraction in the copolymer was 0.13. Fig. 2 shows scanning... 

Figure 2. SEM picture of poly(MPC-co-BMA) surface after contact with human whole blood in the absence of anticoagulant for 15 min. (from ref. 11 with permission).

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