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In vivo evaluation of injectable thermosensitive polymer with time‐dependent LCST
Author(s) -
Henderson Eric,
Lee Bae Hoon,
Cui Zhanwu,
McLemore Ryan,
Brandon Tedd A.,
Ver Brent L.
Publication year - 2008
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.32179
Subject(s) - lower critical solution temperature , biocompatibility , materials science , swelling , in vivo , implant , copolymer , biomedical engineering , polymer , polymer chemistry , surgery , composite material , medicine , biology , microbiology and biotechnology , metallurgy
The focus of this study was to examine the biocompatibility, time‐dependent LCST, and bioerodable properties of a copolymer system composed of NIPAAm, dimethyl‐γ‐butyrolactone (DMBL), and acrylic acid (AAc). Sprague Dawley rats were subcutaneously injected with 25 wt % solutions of poly(NIPAAm‐ co ‐DMBL‐ co ‐AAc). At predetermined times, animals were sacrificed and polymer implants were recovered for characterization via 1 H‐NMR. In addition, polymer‐contacting tissue sections were harvested and processed for histology. The biocompatibility of the implants was assessed by counting the number of fibroblasts and leukocytes present at the tissue‐implant interface. The LCST data obtained from the in vivo implants was shown to agree with that of in vitro findings. Implant mass was shown to decrease after 4 days, indicating accelerated diffusion rates with increased implant swelling, hydrolytic degradation was confirmed with 1 H‐NMR measurements. The cellular presence at the copolymer implant‐tissue interface was shown to return to that of normal tissue 30 days postimplantation, which suggests a normal wound healing response. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009