**2.2.2.1 Evaluation of biocompatibility of TiNi SMA surfacely-modified**

The samples before and after anodic-oxidation respectively were dipped into 25ml SBF solution of PH7.40. The working area was 10mm×10mm, and the non-working one was

2. Dynamic coagulation time test Blood would be activated to coagulate and to affect platelet's formation and function as a material connects with blood. And blood coagulation is a result from a series of reaction in blood. There are two processes which would initiate coagulation, that is, intrinsic coagulation (activated by coagulation factor XII) and extrinsic coagulation reactions. Firstly, prothrombin factor XII was changed into active factor XII a; the active XIIa made the coagulation factor XI change into an activation factor XIa, and furthermore made factor IX activate to be IXa; then the activated IXa combined with the factor VIII, phosphatide and C2+ ions to form a complex compound, which would make factor X change into activation factor Xa; furthermore, the active factor Xa combined with factor Va, phosphatide and C2+ to form the complex compound which would make prothrombin change into thrombin; finally, the thrombin made fibrinogen molecules change into fibrinogen monomer, then into the fibrin colloid under the action of activated factor XIII a, thus forming the blood clots. On the other hand, the extrinsic clotting system, activated by tissue factor and VII factor, directly made the factor X activate to be Xa, the next process emerged was as the same as the intrinsic one's[15]. The process of blood coagulation shows that globin and fibrin in blood on material's surface would bring about activation of the coagulation factor, thus causing fibrin to form and to coagulate. At the same connecting time, by the experiment of dynamic coagulation time in vitro, the activation degrees of different materials on intrinsic coagulation factor can be compared. The activation degrees on coagulation are different, so are the coagulation degrees. With the time of material connecting to blood, coagulation degrees increases correspondingly. The dynamic coagulation time curve is a relation curve to absorbance and time. The more smooth the curve is, the longer the coagulation time lasts, it shows, and the lower the degree activated by coagulation is. And the longer the coagulation time lasts, it shows, the lower the degree for a material to bring about thrombus is, and the better the material's anti-coagulating property is.

The experimental materials were the examples of TiNi SMA, TiNi SMA after anodicoxidation and TiNi SMA after cathodic-electrodeposition respectively. The size of all the

SBF (Simulated body fluid) solution[16] (making up to PH7.40 with diluted hydrochloric acid

SBF solution ingredient: Na2SO4 0.07g + Na2HPO4 0.36g + NaHCO3 0.35g + NaCl 7.88g +

The samples before and after anodic-oxidation respectively were dipped into 25ml SBF solution of PH7.40. The working area was 10mm×10mm, and the non-working one was

important to alleviate erythrocyte damage.

**2.2 Experimental methods** 

**2.2.1 Experimental materials and media** 

KCl 0.37g + MgCl2 0.31 + CaCl2 0.28g + H2O 1L.

and NaOH solution)[17] and fresh blood of New Zealand rabbit.

**2.2.2.1 Evaluation of biocompatibility of TiNi SMA surfacely-modified** 

samples was in 10mm×10mm×1mm.

**2.2.2 Experimental methods** 

of a toxic substance which can produce haemolysis reaction is higher than that of the one which can only produce toxic effect. For the biomedical materials, it is extremely coated with silica gel. Dipping for 7d in a water bath at 37C. The deposition of the Ca/P layer on the surface was detected with Finder 1000 type of EDS.

The samples before and after cathodic-electrodeposition respectively were dipped into 25ml SBF solution of PH7.40. The working area was 10mm×10mm, and the non-working one was coated with silica gel. Dipping for 7d in a water bath at 37C1C, the solution was changed every two days. The deposition of the Ca/P layer on the surface was detected with Finder 1000 type of EDS. And the hydroxyapatite (HA) on the surface was analyzed with D/max 2000type of X-ray diffractormeter (XRD).
