Polymersome-stabilized doxorubicin-lipiodol emulsions for high-efficacy chemoembolization therapy.

Transarterial chemoembolization (TACE) with free doxorubicin-lipiodol emulsions (free DOX/L) is a favored clinical treatment for advanced hepatocellular carcinoma (HCC) patients ineligible for radical therapies; however, its inferior colloidal stability not only greatly reduces its tumor retention but also hastens drug release into blood circulation, leading to suboptimal clinical outcomes. Here, we find that disulfide-crosslinked polymersomes carrying doxorubicin (Ps-DOX) form super-stable and homogenous water-in-oil microemulsions with lipiodol (Ps-DOX/L). Ps-DOX/L microemulsions had tunable sizes ranging from 14 to 44 µm depending on the amount of Ps-DOX, were stable over 2 months storage as well as centrifugation, and exhibited nearly zero-order DOX release within 15 days. Of note, Ps-DOX induced 2.3-13.4 fold better inhibitory activity in all tested rat, murine and human liver tumor cells than free DOX likely due to its efficient redox-triggered intracellular drug release. Interestingly, transarterial administration of Ps-DOX/L microemulsions in orthotopic rat N1S1 syngeneic HCC model showed minimal systemic DOX exposure, high and long hepatic DOX retention, complete tumor elimination, effective inhibition of angiogenesis, and depleted adverse effects, significantly outperforming clinically used free DOX/L emulsions. This smart polymersome stabilization of doxorubicin-lipiodol microemulsions provides a novel TACE strategy for advanced tumors.

Self-assembly of paramagnetic amphiphilic copolymers for synergistic therapy.

Engineering nanoparticles (NPs) with multifunctionality has become a promising strategy for cancer theranostics. Herein, theranostic polymer NPs are fabricated via the assembly of amphiphilic paramagnetic block copolymers (PCL-b-PIEtMn), in which IR-780 and doxorubicin (DOX) were co-encapsulated, for magnetic resonance (MR) and near infrared fluorescence (NIRF) imaging as well as for photo thermal therapy (PTT)-enhanced chemotherapy. The synthesized amphiphilic paramagnetic block copolymers demonstrated high relaxivity (r1 = 7.05 mM-1 s-1). The encapsulated DOX could be released with the trigger of near infrared (NIR) light. In vivo imaging confirmed that the paramagnetic NPs could be accumulated effectively at the tumor sites. Upon the NIR laser irradiation, tumor growth was inhibited by PTT-enhanced chemotherapy. The advantages of the reported system lie in the one-step convergence of multiple functions (i.e., imaging and therapy agents) into a one delivery vehicle and the dual mode imaging-guided synergistic PTT and chemotherapy. This study represents a new drug delivery vehicle of paramagnetic NPs for visualized theranostics.