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Interaction between polymeric materials and tissue -- biodeterioration of polymeric materials
The Bulletin of Tokyo Medical and Dental University
|December 1, 1975
Summary
Biomaterial implants like SIS-MMA and SBS showed minor mechanical property changes and surface cracking after 1 year in dogs. Deterioration may result from absorbed body fluids or leached substances, not solely biodegradation.
Area of Science:
- Biomaterials Science
- Polymer Science
- Veterinary Medicine
Background:
- Assessing the in vivo biocompatibility and degradation of various synthetic polymers is crucial for medical applications.
- Understanding the long-term effects of subcutaneous implantation on polymer integrity is essential for device design and patient safety.
Purpose of the Study:
- To evaluate the biodeterioration and biodegradation of several polymers, including styrene-isoprene block copolymer/methyl methacrylate graft copolymer (SIS-MMA) and styrene-butadiene block copolymers (SBS), after 1 year of subcutaneous implantation in dogs.
- To compare in vivo degradation with in vitro aging in saline and air to elucidate degradation mechanisms.
Main Methods:
- Subcutaneous implantation of polymers (SIS-MMA, SBS, polyethylene, 1,2-polybutadiene, polysulfone, PU, EVA) in dogs for 1 year.
- Comparative aging of materials in physiological saline (37°C) and air (room temperature) for 1 year.
- Assessment of material changes using mechanical property testing, viscometry, X-ray diffractometry, infrared spectroscopy, and microscopy.
Main Results:
- Implanted polymers exhibited slight mechanical property deterioration compared to in vitro/air-aged samples.
- SIS-MMA and SBS showed surface cracking under microscopy; SIS-MMA suggested main chain scission, while SBS indicated cross-linking.
- Infrared spectra and X-ray diffraction patterns remained largely unchanged for most implanted polymers (except SIS-MMA), and molecular weights were stable, contrary to expectations for PU and EVA.
Conclusions:
- Mechanical property deterioration in vivo is not solely due to biodegradation but can be influenced by absorption of biological constituents or leaching of low-molecular-weight substances.
- The observed intactness of some polymers like PU and EVA suggests a complex degradation profile that warrants further investigation.
- Surface morphology changes and molecular alterations in SIS-MMA and SBS indicate specific degradation pathways under in vivo conditions.