Tumor-targeted and multi-stimuli responsive drug delivery system for near-infrared light induced chemo-phototherapy and photoacoustic tomography

Abstract In this work, a tumor-targeted and multi-stimuli responsive drug delivery system has been developed for combining photoacoustic tomography imaging with chemo-phototherapy. We utilized a kind of near infrared (NIR) resonant material-hollow mesoporous copper sulfide nanoparticles (HMCuS NPs) to encapsulate doxorubicin (DOX). After that, the outer surface of HMCuS NPs was capped with multifunctional hyaluronic acid (HA) simultaneously as smart gatekeeper as well as tumor targeting moiety. Herein, HMCuS-HA could serve as a powerful contrast agent for photoacoustic tomography (PAT) to guide chemo-phototherapy by providing the identification of cancerous lesions. In vitro and in vivo studies, the nanoplatform (DOX/HMCuS-HA) pinpointed MCF-7 cells via CD44 receptor-mediated endocytosis pathway. Subsequently, intracellular enzyme-responsive controlled drug release would take place in lysosome after the HA degradation by hyaluronidase. Under near infrared (NIR) light irradiation, HMCuS NPs could not only effectively convert NIR light into heat for photothermal therapy, but also generate high levels of reactive oxygen species (ROS) for photodynamic therapy. In addition, NIR light and low pH environment could facilitate intracellular tunable drug release with spatial/temporal resolution, and thus synergistic combination of chemo-phototherapy should be simultaneously driven by an 808 nm laser irradiation, which brought out an outstanding therapeutic effect. In vivo optical imaging demonstrated that HMCuS-HA significantly enhanced targeting and accumulation capacity in tumor site. Furthermore, tumor-bearing mice treated with DOX/HMCuS-HA under NIR irradiation (808 nm, 2 W/cm 2 , 0.5 min) in vivo displayed the highest inhibition ratio of about 88.9%. Taken together, our present study of the tumor-targeted and multi-stimuli responsive drug delivery system provides new insights into multimodality theranostic applications in cancer treatment. Statement of Significance Until now, chemotherapy is still the major therapeutic approach applied in oncology. Despite their pharmacologically efficacy in cancer treatments, most chemotherapeutic agents without tumor-specific targeting ability have brought out serious toxicities to normal tissues. This study provides a promising near infrared (NIR) resonant material-hollow mesoporous copper sulfide nanoparticles (HMCuS NPs) with capping of multifunctional hyaluronic acid (HA) simultaneously as smart gatekeeper as well as tumor targeting moiety to address the above problem. After the nanoplatform (DOX/HMCuS-HA) pinpointed breast cancer cells via CD44 receptor-mediated endocytosis pathway, intracellular multi-stimuli responsive controlled drug release would take place with remarkable spatial/temporal resolution. Then photoacoustic tomography (PAT) and synergistic combination of chemo-phototherapy would be simultaneously driven by the same NIR irradiation in a coordinated way, which brought out an outstanding theranostic effect. This work can arouse broad interests among researchers in the fields of nanomedicine, nanotechnology, and drug delivery system.