Visualization photofragmentation‐induced rhodamine B release from gold nanorod delivery system by combination two‐photon luminescence imaging with correlation spectroscopy

Abstract

Plasmon-enhanced gold nanorod (AuNR) with high photothermal conversion efficiency is a promising lightcontrollable nanodrug delivery system for cancer therapy. Understanding the mechanism for the light-controllable drug release of AuNR delivery systems is important for the development of nanomedicine. In this study, the rhodamine B (RB) released from AuNR-RB nanodelivery system was quantitated and visualized by using twophoton luminescence (TPL) imaging combined with correlation spectroscopy.The photofragmentation of AuNR induced by femtosecond pulsed laser was revealed by TPL correlation spectroscopy when the laser energy was above the thermal damage threshold of AuNR, and the RB released from this nanodrug delivery system was visualized by TPL imaging. Furthermore, the photofragmentationinduced release of RB from AuNR-RB nanodelivery system was visualized in liv- ing MCF-7 breast cancer cells by TPL imaging combined with correlationAbbreviations: AuNR, gold nanorod; RB, rhodamine B; R6G, rhodamine 6G; DSPE, 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy (polyethylene glycol)-2000PEG]; AuNR-RB, gold nanorod-RB nanodelivery system; DSPE@AuNR-RB, DSPE encapsulated AuNR-RB; FCS, fluorescence correlation spectroscopy; TEM, transmission electron microscope; DLS, dynamic light scattering; FRET, Förster resonance energy transfer.Shiqing Dong and Xiuqin Chen contributed equally to this study.