You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Chemical"].

Please return the output as a JSON object of the format: {"Chemical": ["Arsenic", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Biodegradable core-shell nanoassemblies for the delivery of docetaxel and Zn(II)-phthalocyanine inspired by combination therapy for cancer. Combination therapies for cancer aim to exploit either additive or synergistic effects arising from the action of two species with the final goal to maximize the therapeutic efficacy. In this work, we develop multifunctional nanoparticles (NPs) for co-delivery of the conventional anticancer drug docetaxel (DTX) and the second generation photosensitizer zinc-phthalocyanine (ZnPc) as potential dual carrier system for the combination of chemotherapy and photodynamic therapy (PDT). Biodegradable and amphiphilic block copolymers based on poly(ε-caprolactone) (PCL=B) and poly(ethylene oxide) (PEO=A), with AB and ABA architectures, were assembled in "core-shell" NPs and loaded with both DTX and ZnPc employing the melting/sonication method. Hydrodynamic diameters within the range 60-100nm and low polydispersity indexes were obtained. Zeta potential was negative for all the formulations and unaffected by drug encapsulation. Concerning drug loading ability of NPs, the entrapment efficiency was related to initial ZnPc/DTX ratio. Steady-stationary and time-resolved emission fluorescence measurements pointed out the embedding of monomeric ZnPc in the NPs, excluding the presence of ZnPc self-supramolecular oligomers. The release of DTX was biphasic whereas ZnPc remained mainly associated with NPs. Singlet oxygen generation was observed when ZnPc-loaded NPs were irradiated at 610nm within a 45min time range, despite that ZnPc was not released in the medium. Stability of NPs in the presence of serum proteins and plasma was excellent and no toxicity toward red blood cells was found. NPs cytotoxicity was evaluated in HeLa cells irradiated for 30min with a halogen lamp. After 72h, viability of cells treated with ZnPc/DTX-loaded NPs strongly decreased as compared to NPs loaded only with DTX, thus showing a combined effect of both DTX and ZnPc. Superior antitumor activity of ZnPc/DTX-loaded NPs as compared to DTX-loaded NPs was confirmed in an animal model of orthotopic amelanotic melanoma, thus pointing to the application of PEO-PCL NPs in the combined chemo-photodynamic therapy of cancer.
{"Chemical": ["zinc", "PEO", "PCL", "poly(\u03b5-caprolactone)", "phthalocyanine", "docetaxel", "Zn(II)", "poly(ethylene oxide)", "DTX", "oxygen", "ZnPc"]}