Stable and
tumor-targeting multifunctional wormlike
polymer vesicles simultaneously loaded with superparamagnetic
iron oxide (
SPIO) nanoparticles (NPs) as magnetic resonance imaging (MRI)
contrast agent and anticancer
drug doxorubicin (DOX) were developed for targeted
cancer therapy and ultrasensitive MR imaging. These multifunctional wormlike
polymer vesicles were formed by heterobifunctional amphiphilic triblock copolymers R (R = methoxy or
folate (FA))-PEG(114)-PLA(x)-PEG(46)-
acrylate using a double
emulsion method. The long PEG segments bearing methoxy/
folate groups (CH(3)O/FA-PEG(114)) were mostly segregated to the outer hydrophilic PEG layers of the wormlike vesicles thereby providing active
tumor-targeting ability, while the short PEG segments bearing
acrylate groups (PEG(46)-acrylate) were mostly segregated onto the inner hydrophilic PEG layers of the wormlike vesicles thereby allowing the inner PEG layers to be crosslinked via
free radical polymerization for enhanced in vivo stability. The hydrophobic anticancer
drug, DOX, was loaded into the hydrophobic membrane of the wormlike vesicles. Meanwhile, a cluster of hydrophilic
SPIO NPs was encapsulated into the aqueous cores of the stable wormlike vesicles with crosslinked inner PEG layers for ultrasensitive MRI detection. Cellular uptake of the FA-conjugated wormlike vesicles facilitated by the
folate receptor-mediated endocytosis process was higher than that of the FA-free vesicles thereby leading to high cytotoxicity against the HeLa human cervical tumor cell line. Moreover, the
SPIO/DOX-loaded wormlike vesicles with crosslinked inner PEG layers demonstrated a much higher r(2) relaxivity value than
Feridex, a commercially available T(2) agent, which can be attributed to the high
SPIO NPs loading level as well as the
SPIO clustering effect. These unique stable and
tumor-targeting multifunctional
SPIO/DOX-loaded wormlike
polymer vesicles would make targeted
cancer theranostics possible thereby paving the road for
personalized medicine.