A Montmorillonite-Based\nPickering Nanoemulsion for\nthe Integration of Photothermal Therapy and NIR-Responsive Drug Delivery

Chemo/photothermal combination therapy is a promising\nand practical\napproach for cancer treatment which calls for certain nanovehicles\nto achieve the spatiotemporal co-occurrence of photothermal conversion\nand drug delivery. Herein, we developed a montmorillonite-based Pickering\nemulsion equipped with a near-infrared photothermal agent (indocyanine\ngreen, ICG) and anticarcinogen (paclitaxel, PTX). With both montmorillonite\nand ICG functioning as interfacial stabilizers, the Pickering emulsion\nshowed good stability and nanoscale droplet size, which were favored\nfor cellular applications. Due to the vast oil–water interface,\nwhere the majority of amphiphilic ICG was prone to distribute, the\nPickering nanoemulsion could achieve a higher local concentration\nof ICG than the aqueous solution, therefore leading to a higher local\nphotothermal performance under near-infrared irradiation. The Pickering\nnanoemulsion exhibited fast cell penetration, which promoted the photothermal\ntherapeutic effect of ICG. Moreover, the inner phase of the Pickering\nnanoemulsion also facilitated the loading of PTX, further improving\nits killing efficacy against cancer cells under near-infrared irradiation,\nbecause the photothermal conversion of the Pickering nanoemulsion\ncould not only cause heat damage by itself but also promote the loaded\nPTX to diffuse out and induce cell death. Therefore, this clay-based\nPickering nanoemulsion as a nanovehicle could realize the synergy\nof chemo- and photothermal therapy.