Low Power Density Actuation of Near-infrared Light-Driven AgBiS2/mSiO2 Nanomotors

Photothermal nanomotors are hybrid nanosystems that convert incident radiation into motion. These systems possess the capability to perform tasks on small-scale objects in their vicinity in a controllable manner by manipulating the intensity and duration of the incident radiation. In the biomedical field, near-infrared (NIR) light within the wavelength range of 650 nm to 1350 nm is commonly utilized to generate propulsion due to its extensive tissue penetration depth and low phototoxicity. Several hybrid nanosystems have been proposed [1, 2] as light-driven nanomotors capable of achieving velocities exceeding 20 m/s under NIR actuation. However, reported NIR light-driven nanomotors typically operate under power densities higher than ~2 W/cm2, which is well above the safety standard for biomedical application (~0.3 W/cm2 at 808 nm). In this contribution, we report on fabrication, characterization, and mobility analyses under 808 nm NIR light excitation of hybrid nanosystems composed of silver bismuth sulfide (AgBiS2) and mesoporous silica (mSiO2). It will be shown that efficient actuation of the hybrid nanosystems can be achieved by 808 nm irradiation of power density lower than 0.6 W/cm2 . In addition, the influence of the photothermal actuation on the internalization of AgBiS2/mSiO2 nanoparticles in A375 melanoma cells will be briefly discussed.