Biomedical Engineering Reference
In-Depth Information
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Figure 5.3
(A) A novel thermo-responsive hyperbranched poly(amine-ester). (B)
Temperature dependence of the light scattering intensity. (C) Cell
viability against COS-7 cells at different polymer concentrations
compared to the control (PEI). (D) Cumulative release of drug from a
DOX-loaded delivery system.
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into the matrix. Therefore, sustained release technology comes true through
controlling the external oscillating magnetic field, as shown in Figure 5.4.
5.3.1.3 Redox Responsiveness
As a thiol-containing tripeptide, glutathione (GSH) is found in human blood
plasma in micromolar concentrations, whereas it is around 10 mM in the
cytosol. Especially, the concentration of cytosolic GSH in some tumor cells has
been found to be a couple of times higher than that in normal cells.
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Owing to
the existence of a different order of magnitude in the redox potential between
the mildly oxidizing extracellular milieu and the reducing intracellular fluids,
redox-sensitive micelles have drawn great attention for intracellular drug and
gene delivery among those various smart vehicles. Materials incorporating
disulfide bonds have been explored for this purpose, which can be cleaved in
the presence of reducing agents such as GSH. Therefore, disulfide-containing
polymeric micelles can facilitate intracellular release of the encapsulated drug
and gene by the cleavage of this bond.
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Until now, redox-responsive
amphiphilic HBPs and their nanosized assemblies have become one of the
