Biomedical Engineering Reference
In-Depth Information
biocompatibility. and unique superparamagnetic characteristic as a nonvi-
ral vector (Arsianti et al. 2010). However, its fast aggregate propensity and
low colloidal stability needed modification to achieve better gene delivery
(Chorny et al. 2007).
Core/shell Fe3O4@SiO2 nanoparticles modified with PAH was manufac-
tured as a vector for EGFP plasmid DNA delivery demonstrating a fairly
high expression level (Shi et al. 2011). Similarly, taking advantage of the syn-
ergistic effect, covalently conjugated PEI and superparamagnetic iron oxide
nanoparticles was confirmed to be conducive to effective DNA binding and
enhanced cellular uptake (Namgung et al. 2010). Despite the progress, such
coated magnetic nanoparticles displayed only moderate transfection effi-
ciency compared to other kinds of hybrid materials.
7.4 Conclusion
By introducing the three kinds of inorganic and organic composites materi-
als for applications in tissue engineering and bone regeneration and gene
delivery, we learn a lot about the latest development in bone repair. As the
first generation materials applied in bone regeneration, CaP inorganic mate-
rials have the same chemical ingredients as the natural bone. But without cell
and blood nurturing, CaP inorganic materials' physical and biological char-
acteristics cannot satisfy the requirements of bone regeneration. For porous
mesopore bioglass (MBG), proposed as a new class of bone regeneration
materials, their apatite-formation and drug-delivery properties promises it
a good development in bone regeneration. The highly ordered mesoporous
arrangement of cavities permits the confinement of different drug molecules
to be subsequently released, acting as controlled delivery systems. However,
the material's inherent brittleness and high degradation and surface insta-
bility are major disadvantages, which compromise its mechanical strength
and cytocompatibility as a biological scaffold. Actually, different composites
have their own advantages, but we do not find the best composite materi-
als in bone repair and regeneration. As to gene delivery, organics' fast deg-
radation and weak mechanical strength, and inorganics' weak interactions
between the inorganic vector and the ribonucleic acid molecules restrict their
applications. Under this situation, bioactive organic and inorganic composite
materials offer unique biological, electrical, and mechanical properties key
to designing an excellent gene delivery system.
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