Biocompatibility assessment of polytetrafluoroethylene/wollastonite composites using endothelial cells and...

The aim of the study was to prepare a composite of polytetrafluoroethylene/wollastonite (PTFE/W) and evaluate its biocompatibility with endothelial cells. A composite of PTFE with wollastonite in the proportion 90/10 w/w was prepared. The dynamic storage modulus of composite is found to increase from 260 to about 453 MPa at room temperature while a marginal increase is observed in the compressive modulus. Higher values of storage modulus of PTFE/W relative to pristine PTFE over a range of temperature indicated the contribution of wollastonite in improving the rigidity of PTFE. Electron microscopic visualization of composite surface indicates suitable morphology for cell growth with the cross-section showing no evidence of bonding between PTFE and wollastonite. The water contact angle of the composite indicates increased hydrophilicity over native PTFE due to the presence of wollastonite. A direct-contact test did not show any deleterious effects on endothelial cell morphology and viability, indicating its compatibility. Leached-out products (LOP) from the composite were determined to be non-toxic as tested by tetrazolium (MTT) and Neutral red uptake (NRU) assays. Mouse peritoneal macrophages cultured in the presence of the composites did not show upregulation of activation markers such as CD11b/CD 18 (Mac-1), CD45, CD 14, and CD86 (B7.2) in comparison to macrophages cultured in contact with PTFE alone, indicating its non-activating nature. LOP did not induce proliferation of mouse splenic lymphocytes suggesting its immuno-tolerance. In static incubation assay contact with composite did not lead to hemolysis thus exhibiting preliminary hemocompatibility of the material. Suitable physico-chemical properties and well tolerance by endothelial cells and macrophages make this composite a prospective biomaterial. One could foresee the applications of this composite in areas where materials need to possess high rigidity and are subject to elevated temperatures.