Biomedical Engineering Reference
In-Depth Information
14.5 Characterization of MGs
516
14.5.1 Pore Volume of MGs
516
14.5.2 Characterization of Porous Structure Using Different
Microscopy Techniques
518
14.6 Biomedical Application of MGs
522
14.7 Conclusion and Outlook
525
Acknowledgments
525
References
525
14.1 OVERVIEW
Design of supermacroporous polymeric materials with controlled porosity and
gel surface chemistry is important in the fi eld of biomaterials. The macroporous
gels with a broad variety of morphologies are prepared using cryotropic gelation
technique, meaning gelation at subzero temperatures (so-called
cryogelation
).
The cryogelation technique allows for the formation of biocompatible macro-
porous materials with unique properties such as open and highly permeable
porous structure, tissue-like elasticity, and excellent mechanical strength. Proper
control over solvent crystallization (formation of solvent crystals) and rate of
chemical reaction during the cryogelation allows for the reproducible prepara-
tion of macroporous polymeric materials with tailored properties.
14.2 INTRODUCTION
The development of new macroporous (with pore size above 1
m) functional
polymeric materials for biomedical applications is of great interest. Hydrophilic
macroporous materials designed from natural and synthetic polymers are impor-
tant in the fi eld of biomaterials and used as matrices for controlled drug delivery,
as wound dressing and as scaffolds for cell growth within the tissue engineering
fi eld [Cai et al., 2002; Chen et al., 1995; Hentze and Antonietti, 2002; Lai et al.,
2003; Miralles et al., 2001; Peppas et al., 2000; Shapiro and Cohan, 1997]. An
important approach to design the biomaterials is to involve the preparation of
co-polymers with various functional groups that permit the attachment (grafting)
of polymer chains with bioactive substances that can induce tissue in-growth.
The biocompatible synthetic polymers as poly(2-hydroxyethyl methacrylate)
(pHEMA) [Kaufman et al., 2006; Kroupova et al., 2006; Vijayasekaran et al.,
2000], poly(ethylene glycol) (PEG) [Sannino et al., 2006; Sawhney et al., 1993]
and poly(vinylpyrrolidone) (PVP) [Engström et al., 2006] were shown to be
attractive for the development of biocompatible materials for drug delivery and
tissue engineering. Among polysaccharides, alginate, chitosan and dextran have
found various biomedical applications due to their bioavailability and biocom-
patibility [Ito et al., 2007; Lai et al., 2003; Levesque et al., 2005; Levesque and
Shoichet, 2006; Mi et al., 2001; Miralles et al., 2001; Shapiro and Cohan, 1997].
μ
Search WWH ::
Custom Search