Effective Eradication of Tumors by Enhancing Photoacoustic‐Imaging‐Guided Combined Photothermal Therapy and Ultrasonic Therapy

Exploiting a comprehensive strategy that processes diagnosis and therapeutic functions is desired for eradicating tumors. In this study, two versatile nanoparticles are introduced: one is polyethylene glycol‐ and polyethyleneimine‐modified gold nanorods (mPEG–PEI–AuNRs), and the other is formed by electrostatic interactions between mPEG–PEI and calcium carbonate nanoparticles (mPEG–PEI/CaNPs). These two nanoparticles possess following favorable properties: 1) mPEG–PEI–AuNRs and mPEG–PEI/CaNPs show not only high cell uptake in acidic tumoral pH, but also efficient accumulation in tumors with prolonged circulation. 2) mPEG–PEI/CaNPs can generate carbon dioxide (CO2) bubbles in acidic tumoral environment and the photoacoustic (PA) signals from mPEG–PEI–AuNRs can be enhanced with the generation of CO2 bubbles. 3) The tumors can be eradicated by combining photothermal therapy (PTT) with ultrasonic therapy (UST) under the near‐infrared (NIR) laser and ultrasonic irradiation with the presence of mPEG–PEI–AuNRs and CO2 bubbles from mPEG–PEI/CaNPs. The detailed evaluation of cellular uptake, photothermal property of mPEG–PEI–AuNRs, CO2 bubbles’ generation from mPEG–PEI/CaNPs, imaging, and combined PTT and UST are carried out in vitro or in vivo. This work has great potential usage for diagnosis and treatment in the future. Two versatile nanoparticles are introduced: one is polyethylene glycol‐ and polyethyleneimine‐modified gold nanorods (mPEG–PEI–AuNRs), and the other is composed of mPEG–PEI and calcium carbonate nanoparticles (mPEG–PEI/CaNPs). mPEG–PEI/CaNPs can generate CO2 bubbles in acidic tumoral environment, enhancing the photoacoustic signals from mPEG–PEI–AuNRs. The tumors can be eradicated by combining photothermal therapy with ultrasonic therapy.