Renal‐Clearable Nickel‐Doped Carbon Dots with Boosted Photothermal Conversion Efficiency for Multimodal Imaging‐Guided Cancer Therapy in the Second Near‐Infrared Biowindow

Abstract

Photothermal agents with absorption in the second near‐infrared (NIR‐II) biowindow have attracted increasing attention for photothermal therapy (PTT) on account of their deeper tissue penetration capacity. However, most of the current NIR‐II photothermal agents exhibit low photothermal conversion efficiency (PCE) and long‐term biotoxicity. To overcome these shortcomings, herein, nickel and nitrogen co‐doped carbon dots (Ni‐CDs, ≈4.6 nm) are prepared via a facile one‐pot hydrothermal approach for imaging‐guided PTT in the NIR‐II window. The Ni‐CDs exhibit significant absorption in the NIR‐II region with a distinguished PCE as high as 76.1% (1064 nm) and have excellent photostability and biocompatibility. Furthermore, the Ni‐CDs can be employed as photothermal, photoacoustic, and magnetic resonance imaging contrast agents because of their outstanding photothermal effect and instinctive paramagnetic feature. The Ni‐CDs demonstrate significant PTT efficacy of tumor upon 1064 nm irradiation with a low power density (0.5 W cm−2). The Ni‐CDs can be eliminated from the body via a renal filtration pathway, thereby minimizing their long‐term biotoxicity. Therefore, this work provides a simple and feasible approach to develop photothermal agents with remarkable PCE in the NIR‐II region, presenting good biosafety for multimodal imaging‐guided PTT of tumor.

In Vivo Biodistribution, Clearance, and Biocompatibility of Multiple Carbon Dots Containing Nanoparticles for Biomedical Application

“…It has been reported that glomerular filtration by the kidneys is highly size-selective [40,41]. Previous in vivo biodistribution studies of single carbon dots with a diameter less than 10 nm proved that the kidneys were the main clearance organ [42][43][44]. Our results indicate that the CDs@PEI nanoparticles with approximately 100 nm in diameter could be excreted from the intestine in the feces.…”

Architecting polyelectrolyte hydrogels with Cu-assisted polydopamine nanoparticles for photothermal antibacterial therapy

“…In addition, the stability of the specimens during the four repeated laser on-off cycles was also evaluated. As a result, the photothermal conversion efficiency was calculated as follows [ 30 , 31 ]: where T max,spe denotes the maximum temperature of tested specimens; T max, water denotes the maximum temperatures of water; I denotes the laser power; A 808 is the absorbance value of tested specimen aqueous solution at 808 ​nm; m i denotes the water mass; C p,i denotes the water heat capacity; θ is the system constant.…”

Carbon Dots as a Potential Therapeutic Agent for the Treatment of Cancer‐Related Anemia

“…[28] The excellent optical properties and red/near-infrared absorption properties can enable CDs to provide higher penetration depth and lower phototoxicity in tissues, and meanwhile, red/near-infrared absorption can make CDs generate higher heat under lower power density laser irradiation, which can be used for photothermal therapy and targeted killing of tumor cells. [29,30] In addition, after absorbing light, some CDs can also be sensitized as photosensitizers, undergo electron/energy transfer reactions, and generate reactive oxygen species for photodynamic therapy. [31,32] The available studies demonstrate that CDs exert direct therapeutic effects in vitro and in vivo, and that they can potentially cure Parkinson's disease and various cancer.…”