Preparation of Photoresponsive Doxorubicin/ICG Microfluidic Nanoparticles and Their Enhanced Anti-B16F10 Melanoma Activity

The clinical treatment of melanoma is severely limited by the rapid development of intrinsic and acquired resistance to conventional chemotherapeutic drugs, such as doxorubicin (DOX), as well as their severe, dose-limiting systemic toxicities. To address this issue, we developed a novel nanoplatform for near-infrared (NIR)- activatable nanoplatform leveraging microfluidics as a precision fabrication tool to overcome the limitations of conventional nanocarrier synthesis, including poor batch-to-batch reproducibility, heterogeneous size distribution, and suboptimal drug co-loading. A photocrosslinkable copolymer, Pluronic F127 diacrylate (F127DA), was synthesized and processed using a custom-designed dual-zone microfluidic chip that integrates sequential flow-focusing and turbulent mixing. This approach enabled the one-step, highly controlled co-encapsulation of DOX and indocyanine green (ICG) into monodisperse F127DA nanoparticles (43.9 ± 0.6 nm, polydispersity index: 0.18) with superior encapsulation efficiency (DOX: 60.4%) and drug loading (12.8%). Upon NIR irradiation, the resulting DOX/ICG@F127DA nanoparticles mediated synergistic chemo-photothermal-photodynamic therapy, as evidenced by potent cytotoxicity (melanoma cell viability reduced to 35%), a significant 3.1-fold increase in reactive oxygen species (ROS) generation, and effective inhibition of cell migration (wound closure rate of 17.2% compared to 21.7% with free DOX). Mechanistically, the NIR-triggered ROS burst induced mitochondrial-mediated apoptosis by dysregulating the Bax/Bcl-2 ratio (increased by 2.7-fold), culminating in an apoptosis rate of up to 68.3%. Collectively, this work establishes microfluidics as a robust and scalable platform for engineering complex nanomedicines and delineates the “NIR light–ROS–Bax/Bcl-2” axis as a critical molecular pathway for overcoming chemoresistance in melanoma. Download: Download high-res image (231KB) Download: Download full-size image