Preparation, characterization and in vitro biocompatibility evaluation of poly(butylene terephthalate)/wollastonite composites

The aim of the study was to prepare composites of poly(butylene terepthalat e)/wollastonite (PBT/W), evaluate their properties and in vitro biocompatib ility. Composites of PET with wollastonite in two different proportions, vi z. 70/30 (PW-30), 50/50 (PW-50) were prepared. The DSC studies indicate mar ginal changes in the melting behavior and enhanced crystallization in PBT/W composites. The mechanical properties of the composites such as tensile mo dulus shows remarkable improvement as a result of incorporation of wollasto nite. SEM studies of fractured surfaces of impact samples showed no evidenc e of bonding between PET and wollastonite. Water contact angle of PW30 and PW50 was 73.7 and 78.7 degrees, respectively. In vitro biocompatibility of PW-30 was evaluated as a representative composite. Direct cell contact test did not show deleterious effects on NIH3T3 fibroblast morphology and DNA i ntegrity indicating its compatibility. Leach out products (LOP) of PW-30 we re evaluated non-toxic as tested by MTT assay. Mouse peritoneal macrophages in contact with PW-30 showed comparable expression of CD 11b/18, CD45, CD1 4 and B7.2 to macrophages in contact with PTFE control indicating its non-a ctivating nature. LOP did not induce proliferation of mouse splenic lymphoc ytes suggesting its immune-tolerance. PW-30 also exhibited preliminary bloo d compatibility. These physical properties and biocompatibility of PBT/W co mposites show their suitability as potential biomaterials. (C) 2001 Elsevie r Science Ltd. All rights reserved.