Although the intriguing plasmonic properties of noble metal nanoparticles originate from the collective oscillations of free electrons in the conduction band, nanoparticles of doped semiconductors may also exhibit metal-like, plasmonic features that are dictated by the resonantly excited free hole oscillations in the valence band. Here, we combine Au, a representative free electron metal, with copper sulfides, a class of plasmonic p-type semiconductors, in a core−shell nanoparticle geometry to construct dualplasmonic hetero-nanostructures displaying unique multiplex optical characteristics dominated by plasmonic hole oscillations in the semiconductor shells, plasmonic electron oscillations in the metallic cores, and interband electronic transitions from the valence to conduction bands. Through deliberately designed colloidal synthesis, we are able to selectively grow nanoshells comprising copper sulfides of specifically targeted crystalline phases and Cu/S stoichiometries, such as covellite (CuS), digenite (Cu 1.8 S), and nonstoichiometric Cu 2−x S, on the surfaces of Au nanoparticle cores. Our synthetic approach enables us not only to finely control the core and shell dimensions but also to systematically adjust the free hole concentrations in the semiconductor shells, which forms the keystone for the fine tuning of multiple optical resonance modes supported by these hybrid hetero-nanostructures. The dualplasmonic Au@copper sulfide core−shell nanoparticles exhibit unique multimodal photothermal and photocatalytic behaviors upon selective photoexcitations of different optical transitions at their characteristic resonant frequencies, allowing us to quantitatively evaluate and rigorously compare the intrinsic photothermal and photocatalytic efficacies of multiple types of hot charge carriers, all photoexcited in the same hybrid nanoparticles but with distinct photophysical origins, excited-state lifetimes, energy distributions, and transfer pathways.

This is the author manuscript accepted for publication and has undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record.

Galvanic replacement reactions dictated by deliberately designed nanoparticulate templates have emerged as a robust and versatile approach that controllably transforms solid monometallic nanocrystals into a diverse set of architecturally more sophisticated multimetallic hollow nanostructures. The galvanic atomic exchange at the nanoparticle/liquid interfaces induces a series of intriguing structure-transforming processes that interplay over multiple time and length scales. Using colloidal Au-Cu alloy and intermetallic nanoparticles as structurally and compositionally fine-tunable bimetallic sacrificial templates, we show that atomically intermixed bimetallic nanocrystals undergo galvanic replacement-driven structural transformations remarkably more complicated than those of their monometallic counterparts. We interpret the versatile structure-transforming behaviors of the bimetallic nanocrystals in the context of a unified mechanistic picture that rigorously interprets the interplay of three key structure-evolutionary pathways: dealloying, Kirkendall diffusion, and Ostwald ripening. By deliberately tuning the compositional stoichiometry and atomic-level structural ordering of the Au-Cu bimetallic nanocrystals, we have been able to fine-maneuver the relative rates of dealloying and Kirkendall diffusion with respect to that of Ostwald ripening through which an entire family of architecturally distinct complex nanostructures are created in a selective and controllable manner upon galvanic replacement reactions. The insights gained from our systematic comparative studies form a central knowledge framework that allows us to fully understand how multiple classic effects and processes interplay within the confinement by a colloidal nanocrystal to synergistically guide the structural transformations of complex nanostructures at both the atomic and nanoparticulate levels.

Background The combination of radiotherapy (RT) and chemotherapy, as a standard treatment for breast cancer in the clinic, is unsatisfactory due to chemoradioresistance and severe side effects. Methods and Results To address these issues, a cancer cell-erythrocyte hybrid membrane-coated doxorubicin (DOX)-loaded gold nanocage (CM-EM-GNCs@DOX) was constructed for near-infrared light (NIR)-activated photothermal/radio/chemotherapy of breast cancer. CM-EM-GNCs@DOX inherited an excellent homologous target ability from the cancer cell membrane and an immune evasion capability from the erythrocyte membrane, together resulting in highly efficient accumulation in the tumor site with decreased clearance. Following the highly efficient uptake of CM-EM-GNCs@DOX in cancer cells, the RT efficacy was remarkably amplified due to the radiosensitization effect of CM-EM-GNCs@DOX, which reduced the needed radiotherapeutic dose. Importantly, with NIR irradiation, CM-EM-GNCs@DOX exerted a high photothermal effect, which not only ruptured CM-EM-GNCs@DOX to release DOX for precise and controllable chemotherapy, but also potentiated chemo/radiotherapy by photothermal therapy. Conclusion Therefore, a highly efficient and safe combined photothermal/radio/chemotherapy approach was achieved in vitro and in vivo by CM-EM-GNCs@DOX, which provided a promising strategy for treating breast cancer.

No abstract