Histocompatibility Of Polyurethane-silk Fibroin Composite With Controlled Release Of Drugs(Aspirin/Heparin)

To investigate the histocompatibility of a novel SF-PU material and traditional biomatereials, the acute phase reaction of was studied to compare the films of traditional biomaterials with a novel blend film of SF-PU (1:1). Dacron, e-PTFE, pure PU, SF-PU (1:1) films were transplanted in rat muscle for1week. The acute phase histocompatibility of different biomaterials were evaluated by using an acute toxicity test, an assessment of local reaction in the muscle, histological examination and hematological examination. Dacron had the worst histocompatibility, while the other transplanted films had slight local inflammatory effection. The films of e-PTFE, pure PU had better histocompatibility in rat muscle than traditional dacron. SF-PU mixed at the dose of1:1that yields best histocompatibility. SF-PU (1:1) blend films to prepare a biomaterial is valuable for the researchers to do further studies. To investigate the histocompatibility of PU modified by SF powder with the addition of aspirin, SF and PU were mixed in a ratio of1:1to prepare SF-PU (1:1) blend films via a phase separation technique, and aspirin was added at doses of either0%,5%or10%(w/w). The influence of different doses of aspirin on histocompatibility of SF-PU (1:1) was studied by using morphology examination, infrared spectroscopy, drug release study and in vivo tests including an acute toxicity test, an assessment of local reaction in the muscle, hematological examination, and histological examination. The blend film of SF-PU (1:1) had better histocompatibility than a traditional film of e-PTFE. The addition of aspirin improved the anti-inflammation and anti-platelet aggregation properties of SF-PU (1:1); however,10%aspirin exerted some side-effects. A limited dose of aspirin can be mixed with SF-PU (1:1) films to prepare a biomaterial that yields better histocompatibility than the traditional e-PTFE and pure SF-PU blend film. Native SF powder carrying heparin was blended with biomedical PU to make novel composite membranes for the controlled release of heparin. The release of heparin from the composite membrane can be adjusted by adjusting the blend ratios of SF and PU, the amount of heparin in the membrane and the membrane thickness. The heparin released from the novel release system has excellent bioactivity. Therefore, the novel heparin release system was used to prepare a Heparin-Aspirin-SF-PU small diameter vascular graft. The controlled release of heparin significantly improved the long-term patency rates in the dog carotid artery transplantation.