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Title: A study of the biocompatibility of poly(L-lactide) particulates
Author: Dawes, E. N.
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 1996
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Particles of a variety of orthopaedic materials have been implicated with bone resorption both in vivo and in vitro. The polymer investigated in this study is poly(L-lactide), a bioresorbable material which has been used in orthopaedics to manufacture screws and pins for fracture fixation. Poly(L-lactide) implants degrade and release particulate debris prior to their resorption. So far, the particles generated during the degradation of poly(L-lactide) implants have not been implicated with bone resorption in human clinical trials however, osteolysis in the vicinity of degrading resorbable implants made of a similar material known as poly(glycolide) has been observed radiographically. The biocompatibility of poly(L-lactide) particles was investigated using both in vitro and in vivo techniques in this project and the findings can be summarised as follows: 1. Exposure of fibroblasts to poly(L-lactide) particulates caused an increase in prostaglandin E2 (PGE2) release from intact viable cells whereas exposure of macrophages to these particles caused PGE2 release due to cell death. 2. The presence of lactate monomer [the ultimate degradation product of poly(L-lactide)], caused alterations in cell mortality, percent lactate dehydrogenase (LDH) release and increases in PGE2 release which were not attributable to osmolarity changes alone. 3. An in vitro transformation assay revealed that poly(L-lactide) particles have the capacity to transform C3H/10T1/2 cells, although there is no evidence to suggest that these particles would cause tumours in humans or other animals. 4. Finally, a "rat pin" model did not show up any evidence of bone resorption in the vicinity of a loaded metallic pin implant, caused by high molecular weight poly(L-lactide) particles although fluorescence microscopy indicated that mineralisation may have been reduced.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available