The influence of porosity on the hemocompatibility of polyhedral oligomeric silsesquioxane poly (caprolactone-urea) urethane.
BACKGROUND
The physio-chemical properties of blood contacting biomaterials play an important role in determining their hemocompatibility. It is shown in literature that surface roughness and porosity have significant effect on hemocompatibility. In this study, we use a biocompatible, low thrombogenic nanocomposite polymer called POSS-PCU to test this hypothesis: would porosity compromise the hemocompatibility of POSS-PCU. We compared the hemocompatibility of POSS-PCU films of various pore sizes with PTFE, which is a commercially available material used in most blood contacting devices.


METHODS
Sterilized POSS-PCU films with different size pores were prepared as samples and porous PTFE film were selected as control. And all samples were subjected to SEM for topograpgy, mechanical test for characterization and hemocompatibility tests to evaluate contact activation, platelet adhesion and activation, as well as whole blood clotting response to the samples.


RESULTS
WCA significantly increased with the pore size of POSS-PCU film, whereas both tensile stress and strain decreased significantly as the sizes of pores increased. However, when compared to PTFE film with same size pores, POSS-PCU films showed both higher tensile stress and strain. Pore size had little impact over POSS-PCU's surface chemistry groups as tested by FTIR analysis. Contact activation and platelet adhesion essay also showed no significant difference between different POSS-PCU samples. However, in whole blood reactions, POSS-PCU with pores size around 2-5μm showed higher BCI than plain films and those with pores size around 35-45μm. POSS-PCU showed lower thrombogencity and higher hemocompatibility comparing with porous PTFE on the aspects of platelet activation, adhesion and whole blood reaction.


CONCLUSIONS
POSS-PCU polymer films as a biomaterial in chronic blood contacting implants show significant lower thrombogencity and higher hemocompatibility than porous PTFE film. It is desirable as a coating or covering material in small diameter stents for treating cardiovascular diseases, cerebral vascular diseases and peripheral arterial diseases.
UCL Centre for Nanotechnology and Regenerative Medicine, Division of Surgery & Interventional Science, University College London, London, United Kingdom. Electronic address: jun.zhao.12@ucl.ac.uk.
Junjie
J
Zhao
UCL Centre for Nanotechnology and Regenerative Medicine, Division of Surgery & Interventional Science, University College London, London, United Kingdom.
Yasmin
Y
Farhatnia
UCL Centre for Nanotechnology and Regenerative Medicine, Division of Surgery & Interventional Science, University College London, London, United Kingdom.
Deepak M
DM
Kalaskar
Guangdong Provincial Hospital of TCM, Guangzhou, PR China.
Yanting
Y
Zhang
UCL Centre for Nanotechnology and Regenerative Medicine, Division of Surgery & Interventional Science, University College London, London, United Kingdom; Royal Free London NHS Foundation Trust Hospital, London, United Kingdom.
Peter E M
PE
Bulter
UCL Centre for Nanotechnology and Regenerative Medicine, Division of Surgery & Interventional Science, University College London, London, United Kingdom; Royal Free London NHS Foundation Trust Hospital, London, United Kingdom. Electronic address: a.seifalian@gmail.com.
Alexander M
AM
Seifalian
D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D001792:Blood Platelets / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D008422:Materials Testing; D053761:Nanocomposites / Q000737:chemistry / Q000648:ultrastructure; D017646:Organosilicon Compounds / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D015539:Platelet Activation / Q000187:drug effects; D010973:Platelet Adhesiveness / Q000187:drug effects; D011091:Polyesters / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D011138:Polytetrafluoroethylene / Q000494:pharmacology; D011140:Polyurethanes / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D016062:Porosity; D013499:Surface Properties
D001672:Biocompatible Materials; D017646:Organosilicon Compounds; D011091:Polyesters; D011140:Polyurethanes; C016240:polycaprolactone; D011138:Polytetrafluoroethylene
Hemocompatibility; Nanocomposite biomaterial; Platelet adhesion; Porosity; Thrombelastograph; Thrombogenicity