Optically active nanomaterials have shown great promise as a nanomedicine platform for photothermal or photodynamic cancer therapies. Herein, we report a gold-nanoclustered hyaluronan nanoassembly (GNc-HyNA) for photothermally boosted photodynamic tumor ablation. Unlike other supramolecular gold constructs based on gold nanoparticle building blocks, this system utilizes the nanoassembly of amphiphilic hyaluronan conjugates as a drug carrier for a hydrophobic photodynamic therapy agent verteporfin, a polymeric reducing agent, and an organic nanoscaffold upon which gold can grow. Gold nanoclusters were selectively installed on the outer shell of the hyaluronan nanoassembly, forming a gold shell. Given the dual protection effect by the hyaluronan self-assembly as well as by the inorganic gold shell, verteporfin-encapsulated GNc-HyNA (Vp-GNc-HyNA) exhibited outstanding stability in the bloodstream. Interestingly, the fluorescence and photodynamic properties of Vp-GNc-HyNA were considerably quenched due to the gold nanoclusters covering the surface of the nanoassemblies; however, photothermal activation by 808 nm laser irradiation induced a significant increase in temperature, which empowered the PDT effect of Vp-GNc-HyNA. Furthermore, fluorescence and photodynamic effects were recovered far more rapidly in cancer cells due to certain intracellular enzymes, particularly hyaluronidases and glutathione. Vp-GNc-HyNA exerted a great potential to treat tumors both in vitro and in vivo. Tumors were completely ablated with a 100% survival rate and complete skin regeneration over the 50 days following Vp-GNc-HyNA treatment in an orthotopic breast tumor model. Our results suggest that photothermally boosted photodynamic therapy using Vp-GNc-HyNA can offer a potent therapeutic means to eradicate tumors.
Conventional cancer targeting with nanoparticles has been based on the assumed enhanced permeability and retention (EPR) effect. The data obtained in clinical trials to date, however, have rarely supported the presence of such an effect. To address this challenge, we formulated intracellular nitric oxide-generating nanoparticles (NO-NPs) for the tumor site-specific delivery of NO, a well-known vasodilator, with the intention of boosting EPR. These nanoparticles are self-assembled under aqueous conditions from amphiphilic copolymers of poly(ethylene glycol) and nitrated dextran, which possesses inherent NO release properties in the reductive environment of cancer cells. After systemic administration of the NO-NPs, we quantitatively assessed and visualized increased tumor blood flow as well as enhanced vascular permeability than could be achieved without NO. Additionally, we prepared doxorubicin (DOX)-encapsulated NO-NPs and demonstrated consequential improvement in therapeutic efficacy over the control groups with considerably improved DOX intratumoral accumulation. Overall, this proof of concept study implies a high potency of the NO-NPs as an EPR enhancer to achieve better clinical outcomes.
Chemiluminescence (CL) has recently gained attention for CL resonance energy transfer (CRET)–mediated photodynamic therapy of cancer. However, the short duration of the CL signal and low quantum yield of the photosensitizer have limited its translational applications. Here, we report CRET-based nanoparticles (CRET-NPs) to achieve quantum yield–enhanced cancer phototheranostics by reinterpreting the hidden nature of CRET. Owing to reactive oxygen species (ROS)–responsive CO2 generation, CRET-NPs were capable of generating a strong and long-lasting photoacoustic signal in the tumor tissue via thermal expansion–induced vaporization. In addition, the CRET phenomenon of the NPs enhanced ROS quantum yield of photosensitizer through both electron transfer for an oxygen-independent type I photochemical reaction and self-illumination for an oxygen-dependent type II photochemical reaction. Consequently, owing to their high ROS quantum yield, CRET-NPs effectively inhibited tumor growth with complete tumor growth inhibition in 60% of cases, even with a single treatment.
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