Polymeric hydrophilic polymers in targeted drug delivery - Artificial Cells, Cell Engineering and Therapy - page 59

contrasting, respectively. Nanoparticles were made by the direct complexation
of positively charged chitosan, negatively charged surface modified CdSe/ZnS
quantum dots and negatively charged Gd-DTPA. The nanoparticles can be used
to target intracellular compartments for enhanced imaging, as well as to
elucidate mechanisms of chitosan uptake into cells.
2.4 Conclusions
A number of targeting strategies along with a survey of representative
hydrophilic polymeric materials used in targeting have been presented.
Targeting is the selective accumulation of drugs at the desired site of therapeutic
action, and numerous strategies have been devised for protecting drug and
preventing drug release prior to reaching the target site, guiding carriers to the
target site, and triggering drug release at the target site.
Even without being thoroughly comprehensive in this survey, it is clear that a
wealth of material chemistry and physical properties can be exploited for targeting
applications. While many encapsulation and delivery techniques have been
successfully implemented using traditional hydrogels, nanoparticles and micelles,
emerging targeting strategies are now focused on creating hybrid, multi-
component systems. In particular, combinations of new environmentally
responsive materials now allow for unprecedented control of sustained drug
delivery, and the use of external triggers further enrich the tool chest of stimuli and
can be exploited to independently control the guidance and trigger drug release.
2.5 References
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