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Novel associated hydrogels for nucleus pulposus replacement
Author(s) -
Thomas Jonathan,
Lowman Anthony,
Marcolongo Michele
Publication year - 2003
Publication title -
journal of biomedical materials research part a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.849
H-Index - 150
eISSN - 1552-4965
pISSN - 1549-3296
DOI - 10.1002/jbm.a.10119
Subject(s) - materials science , vinyl alcohol , polymer , dissolution , self healing hydrogels , ultimate tensile strength , swelling , chemical engineering , polymer chemistry , interpenetrating polymer network , polymer blend , network structure , composite material , copolymer , machine learning , computer science , engineering
Hydrogels of poly(vinyl alcohol) (PVA) and poly(vinyl pyrrolidone) (PVP) blends may provide a material suitable for replacement of the nucleus pulposus of the intervertebral disc. This research examined the stability of these hydrogels under simulated physiological conditions. Polymer dissolution and stability were characterized over 120 days immersion, chemical surface analysis over 56 days immersion, and tensile mechanical behavior over 56 days immersion. Rubber elasticity theory was used by combining mechanical results with swelling data to calculate network characteristics such as the molecular weight between physical crosslinks and density of crosslinks. Properties were examined as a function of PVA/PVP composition as well as PVA molecular weight and PVP molecular weight. Results indicated that PVA/PVP blends prepared with moderate amounts of PVP (0.5–5%) resulted in a polymer network stabilized through interchain hydrogen bonding between hydroxyl groups on PVA chains and carbonyl groups on PVP chains. Most notably, a significant decrease in percentage of polymer mass loss was seen for blends prepared with 143K molecular weight PVA. Surface chemical analysis revealed that PVP unincorporated in the network structure suffered significant dissolution out of the polymer network and into solution. The molecular weight of PVA and PVP were shown to have a significant influence on the blends' network properties. Gels prepared with lower molecular weight PVA resulted in a more stable blend containing a higher density of crosslinks. However, blends prepared with a higher molecular weight PVA showed superior polymer network stability in dissolution studies. The blend that had the best combination of network stability under physiological conditions and a relatively tight, stable, and crosslinked network was prepared with 99% PVA (143K) and 1% PVP (40K). This material is proposed as an implant material for replacement of the degenerated nucleus pulposus. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 1329–1337, 2003