No abstract

Varieties of contrast agents have been developed for photoacoustic (PA) and ultrasound (US) imaging of cancers in vivo. However, access of traditional contrast agents into the sites of tumors has been principally through passive infiltration without any external force, preventing their deep penetration into the tissues of the tumors, and hindering the use of PA and US for deep tumor imaging. The concept of micro/nanomotors has been the focus of increasing attention as active theranostic agents due to their active movement in particular fluids, thereby conducting assigned tasks. Herein, US-propelled Janus mesoporous SiO 2partially-coated gold nanorods (Au NR-mSiO 2 ) were fabricated for deep tumor NIR-II PA imaging and synergistic sonodynamicgas therapy. Following US irradiation, 2,2-azobis[2-(2-imidazolin-2-yl) propane] dihydrochloride (AIPH) loaded in mSiO 2 (Au NR-mSiO 2 /AIPH) generated N 2 microbubbles with high efficiency to achieve nanomotor drive. Due to the deep penetration of US, the nanomotors exhibited a capability to travel deep within sites of tumors, providing enhanced PA/US imaging inside the tumors. Furthermore, the nanomotor-based cancer therapy was demonstrated through synergistic N 2 gas and sonodynamic therapy. The US-propelled nanomotors demonstrated a novel strategy for the simultaneous PA/US dual imaging deep within tumor tissues and precise therapy of large tumors.

Delays in evaluating cancer response to radiotherapy (RT) usually reduce therapy effect or miss the right time for treatment optimization. Hence, exploring timely and accurate methods enabling one to gain insights of RT response are highly desirable. In this study, we have developed an apoptosis enzyme (caspase-3) activated nanoprobe for early evaluation of RT efficacy. The nanoprobe bridged the nanogapped gold nanoparticles (AuNNPs) and the second near-infrared window (NIR-II) fluorescent (FL) molecules (IR-1048) through a caspase-3 specific peptide sequence (DEVD) (AuNNP@DEVD-IR1048). After X-ray irradiation, caspase-3 was activated to cut DEVD, turning on both NIR-II FL and PA imaging signals. The increased NIR-II FL/PA signals exhibited a positive correlation with the content of caspase-3. Moreover, the amount of the activated caspase-3 was negatively correlated with the tumor size. The results underscore the role of the caspase-3 activated by X-ray irradiation in bridging the imaging signals variation and tumor inhibition rate. Overall, activatable NIR-II FL/PA imaging was successfully used to timely predict and evaluate the RT efficacy. The evaluation system based on biomarkertriggered living imaging has the capacity to guide treatment decisions for numerous cancer types.

Manufacturing heteronanostructures with specific physicochemical characteristics and tightly controllable designs is very appealing. Herein, we reported NIR-II light-driven dual plasmonic (AuNR-SiO 2 -Cu 7 S 4 ) antimicrobial nanomotors with an intended Janus configuration through the overgrowth of copperrich Cu 7 S 4 nanocrystals at only one high-curvature site of Au nanorods (Au NRs). These nanomotors were applied for photoacoustic imaging (PAI)-guided synergistic photothermal and photocatalytic treatment of bacterial infections. Both the photothermal performance and photocatalytic activity of the nanomotors are dramatically improved owing to the strong plasmon coupling between Au NRs and the Cu 7 S 4 component and enhanced energy transfer. The motion behavior of nanomotors promotes transdermal penetration and enhances the matter−bacteria interaction. More importantly, the directional navigation and synergistic antimicrobial activity of the nanomotors could be synchronously driven by NIR-II light. The marriage of active motion and enhanced antibacterial activity resulted in the expected good antibacterial effects in an abscess infection mouse model.