Photothermal therapy (PTT) employs photo-absorbing agents to generate heat from optical energy, leading to the 'burning' of
tumor cells. Real-time imaging of in vivo distribution of photothermal agents and monitoring of post-treatment therapeutic outcomes are very important to design and optimize personalized PTT treatment. In this work, we used
chitosan-
stearic acid copolymer (CSO-SA) to encapsulate hollow
gold nanospheres (HAuNS) and near-infrared (NIR) fluorescent tracer, DiR. Then, the surface of nanoparticles was further conjugated with a
peptide (TNYL), which facilitates EphB4-positive
tumor targeting delivery. Using a paired
tumor mode in vivo and a double
tumor-cell co-culture strategy in vitro, we demonstrated the feasibility of increasing the accumulation of our nanoparticles (DiR loaded and TNYL-CSO-SA coated HAuNS (DTCSH)) into EphB4-positive
tumors through interaction between TNYL-
peptide on the nanoparticles and EpHB4 receptors on
tumor cells. When combined with NIR
laser irradiation, our nanoparticles induced more EphB4-positive
tumor cells death in vitro. We further developed optical imaging to temporally and spatially monitor the biodistribution of DTCSH. Under NIR
laser irradiation, PTT exhibited dramatically stronger antitumor effect against EphB4-positive
tumors than EphB4-negative
tumors. This was attributed to enhanced accumulation of our nanoparticles in EphB4-positive
tumors.