Near-infrared induced phase-shifted ICG/Fe3O4 loaded PLGA nanoparticles for photothermal tumor ablation

Chengcheng Niu,Long Wang,Qinghai Peng,Yihe Hu,Ming Zhang,Yan Xu,Senbo An

doi:10.1038/s41598-017-06122-1

Abstract

Near-infrared (NIR) laser-induced photothermal therapy (PTT) uses a photothermal agent to convert optical energy into thermal energy and has great potential as an effective local, minimally invasive treatment modality for killing cancer cells. To improve the efficacy of PTT, we developed poly(lactide-co-glycolide) (PLGA) nanoparticles (NPs) encapsulating superparamagnetic iron oxide (Fe3O4), indocyanine green (ICG), and perfluoropentane (PFP) as synergistic agents for NIR laser-induced PTT. We fabricated a novel type of phase-shifting fluorescent magnetic NPs, Fe3O4/ICG@PLGA/PFP NPs, that effectively produce heat in response to NIR laser irradiation for an enhanced thermal ablation effect and a phase-shift thermoelastic expansion effect, and thus, can be used as a photothermal agent. After in vitro treatment of MCF-7 breast cancer cells with Fe3O4/ICG@PLGA/PFP NPs and NIR laser irradiation, histology and electron microscopy confirmed severe damage to the cells and the formation of many microbubbles with iron particles at the edge or outside of the microbubbles. In vivo experiments in mice with MCF-7 tumors demonstrated that Fe3O4/ICG@PLGA/PFP NPs could achieve tumor ablation upon NIR laser irradiation with minimal toxicity to non-irradiated tissues. Together, our results indicate that Fe3O4/ICG@PLGA/PFP NPs can be used as effective nanotheranostic agents for tumor ablation.

Highlights

Photothermal therapy (PTT) employs a near-infrared (NIR) laser and photo-absorbing agents to generate heat from light energy to “burn” cancer cells[1, 2]
The morphology and structure of Fe3O4/Indocyanine green (ICG)@PLGA/PFP NPs were characterized by SEM and TEM
In TEM (Fig. 2c), scattered black spots with diameter of 10 nm were clearly observed on the shells of Fe3O4/ICG@ PLGA/PFP NPs, confirming the encapsulation of Fe3O4 NPs in the Fe3O4/ICG@PLGA/PFP NPs

Summary

Introduction

Photothermal therapy (PTT) employs a near-infrared (NIR) laser and photo-absorbing agents to generate heat from light energy to “burn” cancer cells[1, 2]. Many studies have focused on liquid perfluorocarbon (PFC) droplets, which can be vaporized into gas bubbles via active US sonication or laser irradiation[48, 49] This property of vaporization has been effectively employed for US imaging[50], cancer therapy via vessel occlusion[51,52,53], targeted drug delivery[54,55,56], and thermal ablation of tumor cells[57, 58]. This technology has yet to be combined with a dual NIR light-absorbing agent along with encapsulation in polymeric NPs toward the development of an effective PTT approach

Methods

Results

Conclusion